University of Bielefeld - Faculty of technology | |
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Networks and distributed Systems
Research group of Prof. Peter B. Ladkin, Ph.D. |
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Back to Abstracts of References and Incidents | Back to Root |
Hiroshi Sogame
| Peter Ladkin
|
July 19, 1996
Various data are recorded continuously in digital PCM signals onto magnetic tape in the DFDR at various with its sampling rates ranging from eight (8) times per second to every 4 seconds.
Data regarding altitude, speed, and bearing are recorded every second. Data regarding time and engine are recorded every four (4) seconds. Data such as acceleration are recorded at a higher sampling rate of four (4) to eight (8) times per second. All the data are incremented every 4 seconds as one frame.
The cockpit clock times on the panel on F/O's side are also recorded on the DFDR. However, the times are not necessarily synchronized with UTC, so the DFDR times were calibrated as follows: radio communications keying data were recorded on DFDR. By correlating these keying data to the times contained on the CVR transcript for the ATC radio communications, the times recorded on DFDR were established.
Data up until 1115:43 were recorded on the DFDR. Since the DFDR manipulates data in the method that one second of data are temporarily accumulated in buffer (as a subframe) and are recorded on magnetic tape within next 0.5 second, by taking into account possible errors in the correlation process, it is recognized that the DFDR stopped operating at approximately 1115:45.
0853 (1700 JST) | The aircraft took off
from Taipei International Airport. |
ca.0914 (1800 JST) | The aircraft reached FL 330, and
flew in accordance with its flight plan toward Nagoya Airport. |
1040:17 (1900 JST) | The aircraft was cleared by
Tokyo Control to PROCEED DIRECT XMC (Kowa VOR/TAC), and
the aircraft flew according to this clearance. |
1045:45 (1900 JST) | The F/O(PF) briefed the CAP (PNF)
on the approach procedure to Nagoya Airport,
go-around procedure, etc. |
1047:35 | While cruising at FL 330, the aircraft was
cleared by Tokyo Control to descend to FL 210, and
began its descent. |
ca.1049:00-ca.1056,00 | During this period,
the CAP (PNF) gave general guidance to the F/O(PF) on
flight procedure and control during approach and landing. |
1058:18 | The aircraft's radio communication was
transferred from Tokyo Control to Nagoya Approach, and the
aircraft continued its approach. |
1059:04 | The F/O(PF) said "CHECKLIST". It is
considered that he requested the
CAP (PNF) to conduct the approach checklist. |
1 l00:05(2OOOJST) | The CAP (PNF) said to the F/O:
"OK, FASTEN LEFT, APPROACH CHECKLIST COMPLETED." |
1100:11 | The CAP (PNF) instructed the F/O (PF) to
control the aircraft at his own discretion and
the F/O (PF) responded by saying "YES". |
1100:12 | The SLATS/FLAPS lever was moved from
0/0 to 15/0. |
1102:35 | The SLATS/FLAPS lever was moved from
15/0 to 15/15. |
1107:22 | Until this time AP No.2 had been engaged;
at this time AP No.1 was additionally engaged. |
1108:26 - 1110:54 | Since the F/O(PF) was concerned
about wake turbulence, the CAP (PNF) taught
him how to deal with it, instructing him to
reduce the speed from 180 kt to 170 kt in order to
extend the separation between themselves and the
aircraft flying ahead. |
1110:52 | The sound of a seat being adjusted was
recorded. This is estimated from the sound spectrum
of the CVR recordings which indicate that the CAP
adjusted his seat upward in preparation for approach. |
1111:35 | With the CAP's (PNF) consent, the F/O(PF)
disengaged both AP No.1 and No.2 in order to
change from automatic operation to manual operation. |
1111:45 | The CAP (')NF) called out
"GLIDE SLOPE ALIVE". |
1111:46 | The F/O(PF) acknowledged this and called
out "go-around altitude 3,000 ft". And then
GO AROUND ALTITUDE was set on ALT SEL before the
FMA displayed GS STAR, as a result of which the
altitude alert sounded at 1111:55. Both the
CAP (PNF) and the F/O(PF) confirmed the above situation. |
1112:19 | The aircraft passed over the outer marker
under manual control by the F/O(PF), and
continued ILS approach. |
1112:41 | The F/O(PF) requested the CAP (PNF) to
set "Flap 20", and in response to this the
CAP (PNF) moved the SLATS/FLAPS lever from 15/15 to 15/20. |
1112:56 | The F/O(PF) requested "Gear Down" to the
CAP(PNF), and the CAP responded by performing the
Gear Down operation. |
1113:14 | The F/O(PF) called to the CAP (PNF) "30/40,
speed V approach 140, landing checklist
please"; the CAP moved the SLATS/FLAPS lever
from 15/20 to 30/40 and called "Landing check
list completed" at 13:27. |
1114:05 | At approximately 1,070 ft pressure altitude, the F/O(PF)
triggered the GO lever. As a result, the engines' thrust
began to increase, the aircraft developed a slight nose-up
tendency and began to deviate above the ILS glide path.
Speed also increased. Engine thrust increase was stopped
at EPR 1.21 about 14:08, and was then slightly reduced to
EPR between 1.17 and 1.18. |
In an attempt to recover the normal descent path, the F/O (PF)
performed a nose-down operation by pushing the control
wheel (The THS position did not change from -5.3°.) | |
However, the aircraft did not descend and, around 1114:10,
leveled off at approximately 1,040 feet pressure altitude. | |
1114:09 | An aural LANDING CAPABILITY CHANGE WARNING was recorded
on the CVR. This sound is considered to have been caused by
the change from LAND mode to GO AROUND mode. |
1114:10 | The CAP (PNF) cautioned the F/O (PF) by saying
" You, You triggered the GO lever,", and the F/O acknowledged,
saying "Yes, Yes, Yes, I touched a little." |
1114:12 | The CAP (PNF) instructed the F/O (PF) to "disengage it",
and the F/O (PF) answered "AY". |
1114:16 | The CAP (PNF) said " That" and the F/O (PF) said "AY" |
1114:18 | During level flight, both AP No.2 and No.1 were engaged in
CMD almost simultaneously. As the FD was in GO AROUND mode,
the APs were also engaged in GO AROUND. At this time, the
elevators were at 3.5° nose-down with the F/O still
pushing the control wheel. |
1114:20 | As the APs were engaged, the THS began to move from
-5.3° toward the nose-up direction. |
In the meantime, the CVR had recorded a sound that is assumed
to indicate activation of the pitch trim control switch. | |
It is considered that the switch was activated by the F/O (PF)
in an attempt to reduce the resistive force on the control wheel.
However, trimming of the THS using the pitch trim control switch
is inhibited during engagement of the AP(s), so the F/O's actions
had no effect. | |
1114:23 | The CAP (PNF) gave the F/O (PF) an order, saying "Push down,
push it down, yeah". This is considered to have been an
instruction to push the control wheel down in order to
correct the descent path that had become too high. |
1114:26 | The CAP (PNF) told the F/O (PF) "You, that --- disengage
that throttle". This is considered to have represented
the CAP's (PNF) instruction to the F/O (PF) to manually
adjust the thrust by moving the throttle toward its
idle position (for the same purpose as in 1114:23,
i.e., to correct the descent path that had become too high). |
1114:29 | The F/O said "Too high". This is considered to have meant
that the aircraft was flying above the normal descent path. |
1114:30 | On noticing that the FMA was still displaying GO AROUND mode,
the CAP (PNF) said to the F/O (PF), "You, you are using the
GO AROUND mode", and then added "It's OK, disengage again
slowly, with your hand on". |
There seems to be a possibility that in response to the
CAP's instruction, the F/O took some action to change
from GO AROUND mode to another mode, but this was not achieved.
The words "with your hand on" seem to have two different
meanings, the first being that the F/O should keep his hand
on the thrust lever and the second that he should keep his hand
on the button to change from GO AROUND mode to another mode. | |
1114:34 | The CVR recorded a sound that is assumed to indicate
activation of the pitch trim control switch. As at
1114:20, however, this operation had no effect. |
1114:37 | The THS moved to -12.30°. |
1114:39 | The CVR recorded a sound that is assumed to indicate activation
of the pitch trim control switch. As at 14:20 and 1114:34,
however, this operation had no effect. |
1114:45 | The CAP (PNF) again pointed out to the F/O (PF) "It's now
in GO AROUND mode". The F/O answered, "Yes, sir". |
Although there seems to be a possibility that the F/O (PF)
took some action to change from GO AROUND mode to another mode,
no mode change was actually made. At and around this point of
time, the pitch angle and AOA increased and the speed decreased,
and to deal with this situation, the F/O increased the thrust
slightly. | |
1114:49 | The F/O (PF) said, "Sir, auto pilot disengaged" and disengaged
both APs. This action was probably taken at the F/O's (PF) own
discretion or under the CAP's (PNF) instruction, but it is not
clear which was the case (the conversation in the CVR record
just prior to the action had been masked by another ATC
communication). |
1114:50 | The sound of Auto Pilot disengagement was recorded on CVR. |
1114:51 | The F/O (PF) said, "Sir, I still cannot push it down." |
1114:57 | With the pitch angle and AOA still increasing, the aircraft
continued to its approach with decreasing speed. At approximately
570 feet pressure altitude, the thrust increased suddenly,
reaching its maximum level at 1115:03. |
This is considered to have been caused by activation of the
alpha floor function due to the AOA exceeding the threshold angle
of 11.50 for SLATS/FLAPS 30/40 configuration. | |
1114:58 | The CAP (PNF) said "I, that land mode?". |
1115:02 | The F/O (PF) reported to the CAP (PNF): "Sir, throttle latched
again Activation of the alpha floor function displays a
symbol "THR-L" on the FMA. |
Owing to the thrust increase following activation of the
alpha floor function at 1114:57, the aircraft's speed and
pitch angle increased; the aircraft stopped descending and
began to climb. | |
At 1115:03, the CAP told the F/O that he would take over
the controls. After doing so, the CAP pushed the control
wheel to the forward limit, but the aircraft still continued
to climb. Around this time the thrust levers were also
temporarily retarded, suggesting that the CAP still intended
to continue approach. | |
1115:04 | The F/O (PNF) said, "Disengage, disengage." Again at 1115:09,
the F/O said "Disengage, dis...". This is interpreted as a
request to the CAP (PF) for the A/THR to be disengaged. |
1115:08 | The CAP (PF) said, "What's the matter with this?". It is
considered that the CAP's words expressed his puzzlement that
the nose-up tendency was continuing, even though he had pushed
the control wheel fully forward and decreased thrust. |
1115:11 | The CAP (PF) re-increased thrust (which he had earlier reduced)
while calling "GO |
lever". At the same time, the CVR recorded the activation
sound of the pitch trim control switch, and the DFDR recorded
the movement of the THS in the nose-down direction. | |
The CAP (PF) said "Damn it, how comes like this?". It is
considered that the CAP's words expressed his puzzlement that
the aircraft pitch angle was still increasing despite his
actions to the contrary (pushing the control wheel fully forward
and retarding the thrust levers). | |
Owing to the re-increased thrust, the aircraft began a
steep climb with increasing pitch angle. Speed, which had
earlier increased, began to decrease. | |
1115:14 | The F/O (PNF) reported go-around to Nagoya Tower. |
1115:17 | Mode 5 warning of the GPWS sounded "Glide Slope" once. It is
estimated that this resulted from a detection of a pseudo-path
angle that occurred at an angle 3 times greater than the normal
path angle. |
1115:18 | The sound indicating passage of the SLATS/FLAPS lever through
the baulk attached gates was recorded twice (see attached Figure 27). |
According to normal go-around procedure, the SLATS/FLAPS lever
should be moved from the 30/40 position one step higher to 15/20.
However, judging from the numbers of times the STATS/FLAPS lever
sound was recorded, it may have been moved beyond the 15/20 position,
perhaps to the even higher 15/0, or 0/0 position. Later, at 15:27,
a sound presumably indicating the SLATS/FLAPS lever's downward
movement passing through the baulk attached gate was recorded on the
CVR. Also on the DFDR is a record showing that the SLATS/FLAPS lever
was set on the 15/15 position at 1115:28. | |
1115:20 | Both thrust levers were retarded almost simultaneously. At
approximately 1115:23, the No.1 thrust lever was retarded to
the vicinity of its idle position and the No.2 thrust lever was
retarded slightly. At approximately 1115:27, both the levers
were back almost to their full thrust positions. |
1115:21 | "He, if this goes on, it will stall," the CAP (PF) shouted.
It is presumed that this remark reflected the CAP's (PF) shock
either when he found the aircraft was continuing to climb steeply
with increasing pitch angle while reducing speed, or when he
noticed the position of the SLATS/FLAPS lever set by the F/O (PNF). |
1115:23 | The master caution (single chime) sounded. It was probably
caused by the tripping of the yaw damper lever. |
1115:25 | The stall warning sounded for two (2) seconds and then stopped.
This was probably due to the following: |
The stall warning began to sound at 1115:25 because the AOA reached |
approximately 16° at 15:22, exceeding the threshold
angle of 15° for the configuration SLATS EXTENDED. However,
Vc dropped below 75 kts. at 1115:27, so the ADC apparently judged
the AOA to be "NO MORE VALID" and terminated the warning function. | |
It is considered probable that around 1115:25, the aircraft
fell into a stall, yet continued to climb until reaching its
highest point. The aircraft remained in a stall condition
until impact. | |
1115:26 | The pitch angle of the aircraft reached the maximum angle
of 52.56°. |
1115:27 | The THS returned to -7.4° from 12.30° where it had been
at 1115:11, and then remained there until 1115:33. |
It is considered that this was probably caused by the tripping
of the pitch-trim lever at 1115:27. | |
1115:28 | The master caution (single chime) was recorded on CVR.
It is considered that this was probably caused by the tripping
of the pitch-trim lever. |
1115:31 | The master caution (single chime) was recorded on CVR.
It is considered that this was probably caused by the tripping of the
ATS Lever. On the CVR the F/O's words, "Set, set," are recorded. It
is considered that these words were probably the F/O's request to
reset something when he saw CAUTION MESSAGE displayed on the ECAM.
Considering the fact that the THS was moved again after about 1115:35,
the F/O probably reset the pitch trim. |
After reaching the highest point at approximately 1,730 ft pressure
altitude, with a pitch angle of 43.80, the aircraft began to descend,
while rolling and yawing greatly to the left and right. There are
records showing that corrective actions were taken by the crew by
means of the ailerons and rudder during this period. | |
1115:31 | The thrust decreased temporarily. |
This was presumably caused by surges that occurred in both
engines. | |
1115:34 |
From this point until just before the impact , the F/O (PF) shouted
"Power" repeatedly. This was linked to his utterance of "Quick push
nose down" at 1115:26 and is assumed to indicate a desire to increase
thrust and thus recover lost speed. |
1115:35 | The CAP (PF) performed a nose-up operation using the control wheel. |
It is considered that the CAP had until then been applying nose-down
input to the elevator in order to decrease the pitch angle, but at
this moment he applied a nose-up input to the elevator in response to
the decrease in pitch angle and the steep descent of the aircraft. | |
1115:37 |
The Mode 2 warning of the GPWS sounded "TERAAIN TERRAIN"
once. Computation of the CAS and AOA that had earlier paused, now
resumed. |
1115:40 |
The aural stall warning, which had stopped at 1115:27, sounded again
and continued until impact. |
1115:45 |
From the conditions in which the CVR and DFDR recordings ended, it was
estimated that the aircraft crashed at approximately 1115:45. |
(1) Concerning activation of the GO lever
It is recognized that the F/O (P/F) triggered the GO lever at 1114:05,
judging from the following: the increase in engine thrust starting
at 1114:05, as recorded on DFDR; the CAP's (PNF) utterance at 1114:06,
the sound of LANDING CAPABWITY CHANGE at 1114:09, the CAP's caution at
1114:10, and the F/O's response at 1114:11, all of which were recorded
on CVR.
The F/O activated the GO lever, causing the FD to change to GO AROUND
mode, and the ATS to be engaged in THE mode.
It is considered that at 1114:06 the CAP said "EH. EH. AH," on seeing
the display change on the FMA.
The F/O (PF) seems to have used ATS with his hand on the thrust
levers, judging from the smooth transitions of both thrust levers
recorded on DFDR until then.
It is considered that the F/O may have mistaken the GO lever for the
AT disconnect push button in an attempt to change the ATS into manual
thrust, or that he tried to move the thrust levers to control the
thrust and thereby inadvertently triggered the GO lever. The reasons
why are not clear, but, at any rate, he inadvertently triggered the GO
lever.
The GO lever of the A300-600R type aircraft is positioned below the
thrust lever knob. The direction that the GO lever is operated in is
the same as the direction in which the thrust lever is retarded, or as
the same direction that the fingers move when gripping the thrust
lever knob With this arrangement, the possibility exists for an
inadvertent activation of the GO lever during normal operation of the
thrust levers (See attached Photograph 51).
(2) Concerning CAP's direction at 1114:12
The CAP gave an instruction to the F/O, saying "Disengage it".
The definite meaning of the word "it" is not found in the CVR records,
but there seem to be two possible meanings -- "Auto Throttle" and "GO
AROUND mode" -- which it could represent. This is inferred from the
following:
The DFDR records show that activation of GO lever led to a thrust
increase; the EPRs stopped at the value of 1.21 at 1114:08. It is
considered that the F/O probably pushed the AT disconnect push button
while holding the thrust levers -- which were moving forwards at the
time -- and then retarded the thrust levers. | |
After this action the EPRs were reduced slightly. It seems that
before 1114:12 the Auto Throttle had already been disengaged by the
F/O, and the FMA display had |
changed to "GO AROUND". | |
It was most likely that the CAP's instruction in this situation meant
that GO AROUND mode should be disengaged, because he must have seen
the FMA display. |
(3) Concerning the CAP's word at 1114:16
At 1114:16, the CAP said "That", and the F/O said "Aye". The precise
meaning of the word "that" is not found in the CVR records, but there
appear to be three possibilities:
(1) | The CAP instructed the F/O to engage the AP(s). | |
(2) | Because the CAP's instruction at 1114:12 had not been
followed, he repeated it. | |
(3) | The CAP's word did not represent an instruction,
because the nuance is ambiguous. In this case, the F/O seemed
to have given the CAP only a response. |
However, it was not possible to determine which of the above
scenarios is the correct one.
(4) Concerning use of AP
According to the DFDR records, both APs were engaged at 1114:18.
Around this time, no verbal exchange as to AP engagement was recorded
on CVR. However, there seem to be the following possibilities
concerning engagement of APs:
(1) | Possibility that the CAP instructed the F/O to engage the APs | |
If it
is assumed that the CAP's word at 1114:16 meant the item (3)-(1)
above, the F/O might have engaged the APs in accordance with the CAP's
instruction. | ||
According to the positions of the thrust levers (throttle resolver angles) recorded on DFDR from 1114:12 to around 1114:18 (which is recorded every 4 seconds with one second time gap between NO.1 and NO.2), the positions of the thrust levers varied slightly respectively, so taking into account the time allowance for the actions taken by the F/O, it is considered possible that the F/O tried to select the LAND mode at first, then once held the thrust levers after taking actions to change mode, and furthermore took action to engage the APs. | ||
(2) | Possibility that the CAP engaged the APs himself | |
(3) | Possibility that F/O engaged the APs himself | |
If it is assumed that the CAP's words at 1114:16 meant
item (3)-02 or (3)-03 above, another possibility is that the F/O
engaged the APs
without the CAP's consent, or without notifying the CAP. In this
case, according to the CVR records, because the F/O had so far
operated during the whole flight based on the CAP's instructions, or
with the CAP's consent in advance, there seems to be a possibility
that the F/O instinctively engaged APs for their assistance. |
However, it was not possible to determine which of the above scenarios is the correct one.
The reason why either the CAP or the F/O engaged the APs may have been that the crew intended to regain the normal glide path by selecting LAND mode and engaging the APs. |
(5) Concerning the operation of Pitch Trim Control Switch
The activation sound of the pitch trim control switch was recorded
on CVR at 1114:20, 1114:34, and 1114:39 respectively. If a hypothesis
is made that the F/O knew that THS trimming operated by the pitch trim
control switch was inhibited during AP engagement, the CAP may
therefore have engaged the APs unknown to the F/O. However, from the
fact that the F/O actually disengaged both APs at 1114:49, he may
finally have recognized that the APs had been engaged by this time.
On the other hand, even though the F/O may have recognized AP
engagement, it is still possible that he may have involuntarily
operated the switch while pushing the control wheel.
(6) Concerning disengagement of GO AROUND mode
The CAP said "You, you triggered the GO lever" at 1114:10, and alerted the F/O (at 1114:30 and 1114:45) to the fact that GO AROUND mode had been engaged. This leads to the possibility that after the F/O had triggered the GO lever, the CAP, watching the FMA display, intended to disengage GO AROUND mode and instructed the F/O to do so. However, it is inferred from the following facts that GO AROUND mode remained engaged.
(1) | THS moved in the direction opposite to the F/O's input at
the control wheel. | |
(2) | Disengagement of GO AROUND mode and engagement of other
modes led AP No.2 to be disconnected, but no data concerning this was
recorded on DFDR. | |
(3) | CAP continued until 1114:45 to alert the F/O to
the fact that GO AROUND mode was still engaged. |
In order to
disengage GO AROUND mode, both lateral mode and longitudinal mode
(except LAND mode) must be selected. Direct access to the LAND mode
button cannot disengage GO AROUND mode (by selection of either lateral
or longitudinal mode a display of GO AROUND on FMA will turn oft).
However, judging that GO AROUND mode still remained engaged, it is
estimated that what the crew's operation on FCU was not correct
procedure to disengage it : he must only have pulled LAND mode button.
And also, taking into account that the CAP said "I, that LAND mode?"
at 1114:58, the CAP seemed to have intended to disengage the GO AROUND
mode and select LAND mode.
The procedure for performing an approach
by disengaging GO AROUND mode once engaged and then engaging LAND mode
is unusual in the final phase of approach. However, the fact that the
crew did not change modes as intended seems to have been due to their
lack of understanding of the Automatic Flight System (AFS).
(7) Concerning the sequence leading up to the out-of-trim situation
After the GO lever was triggered, the sequence leading up to the out-of-trim situation was as follows:
(1) Just before 1114:05
In the landing configuration with landing gear down and SLATS/FLAPS at 30/40, the aircraft continued descent along 30 ILS glide path with a speed of approx. 140 kts., pitch angle of approx. 40, both EPR at approx. 1.1, THS at -5.3°, and the elevator angle (relative to THS) at 0° to 1° nose down. |
(2) Just after 1ll4:05
While crossing approx. 1,070 ft pressure
altitude, the GO lever was activated by the F/O, and when the EPRs
increased to 1.21 at about 14:08, the thrust levers were manually
pulled back slightly. | |
The aircraft increased its speed and pitch angle slightly, deviating above the ILS glide path. The F/O applied push-down input to the control wheel but it was insufficient and also he did not retard the thrust levers sufficiently. These circumstances led the aircraft to level off about 1 ,040ft pressure altitude around 1114:10. For a while the THS had stayed at 5.3° And pitch trim control switch was not operated. |
(3) 1114:18
While the aircraft continued level flight, both APs were engaged in
CMI) with the FD already in GO AROUND mode, and the APs, were brought
into GO AROUND mode. | |
In the meantime, the F/O (PF) had been pushing the control wheel since
14:05, when he had activated the GO lever, in an effort to return to
the normal descent path. | |
At the time when the APs were engaged in CMI), the elevator angle was
3~50 nose-down. The angle decreased to 2.80~2.40 temporarily in the
period between 1114:19 and 1114:20, but the nose-down angle gradually
increased thereafter.
| |
GO AROUND mode was engaged while the F/O was pushing the control
wheel. The AP attempted to move the elevators and THS toward the
nose-up direction, but this resulted in the elevators' function being
overridden and the THS beginning to move in the nose-up direction from
5.3°
| |
However, the nose-down operation of the elevators performed by the F/O
canceled the aerodynamic effect of the THS nose-up which was
controlled by the AP, and the aircraft temporarily continued level
flight. The surface area of THS (including the elevators) is
approximately three times that of the elevators. The aerodynamic
effect per unit travel angle of the THS is therefore considerably
greater than that of the elevators. |
(4) 1114:24
To correct the descent path, the F/O (PF) began to retard the thrust levers and reduced the EPRs from approx. 1.17 to approx. 1.00 by 1114:31. |
As a result, the speed began to decrease from 146 kts., causing the nose-up tendency also to decrease. This retard operation of the thrust levers and the push-down operation of the control wheel by the F/O against the movement of the THS in nose-up direction, together caused the pitch angle to decrease, and the aircraft began to descend around 14:26. |
(5) 1114:30
The pitch angle which had decreased to 1.20 again began to increase. | |
This is considered to be due to the fact that the pitch-up effect
generated by the nose-up movement of the THS became larger than the
pitch-down effect brought about by the push-down operation of the
control wheel from that time on. | |
The speed continued to decrease slowly. As the pitch angle increased, the
AOA also began to increase. |
(6) 1114:37
While crossing approx. 880 ft pressure altitude, the THS reached the
full nose-up position of ~12.30, and the elevator was moved to 8.50 in
the nose-down direction. Around this time, the descent rate was
approximately 1,000 ft/mm. | |
Although the control wheel was still being pushed, the pitch angle and
AOA continued to increase, while the speed continued to decrease. In
order to deal with the continuous decrease in speed, the F/O increased
the thrust slightly. |
(7) 1114:49
While crossing approx. 700 ft pressure altitude, the APs were disengaged, but THS remained ~12.30, and out-of-trim condition continued. |
(8) Concerning activation of Alpha Floor Function (Refer to 3.1.11.6)
Just after the APs were disengaged at 1114:49, the mobility of the
control wheel (being pushed by the F/O(PF)) increased a little,
thereby moving elevators in the nose-down direction; and pitch angle
and AOA decreased. A few seconds later, forward pressure on the
control wheel was loosened a little, and pitch angle and AOA increased
again. When the aircraft crossed approximately 570 ft pressure
altitude at 14:57, as airspeed was 127 kts., both EPRs were 1.04 and
pitch angle was 8.60 and AOA exceeded threshold angle of 11.50 for the
configuration of SLATS/FLAPS 30/40, the alpha floor function was
activated. | |
Although at this point of time, THS was ~l2.30 and the elevator angle was 9~90, the sudden increase of power due to the out-of-trim condition and the activation of the alpha floor function generated a pitch up moment. As for the fact that the F/O (PF) loosened forward pressure on the control wheel a little several seconds after AP was disengaged, it is considered likely that he did so in order to correct the pitch angle. However, even if the F/O (PF) had not loosened forward pressure on the control wheel at this point of time, the AOA, sooner or later, must have been exceeded threshold angle of 11.50 due to the trend of speed, |
pitch angle and the AOA if the aircraft had continued to approach
under the above-mentioned out-of-trim condition. |
(9) Concerning continued approach
The CAP (PNF) had had the F/O perform the PF duty while making an
WS approach. Judging that although the aircraft once deviated above
the glide path after the F/O triggered the Go lever, it began to
return to the normal glide path due to the F/O's fully forward
pressure on the control wheel and reducing the thrust following the
CAP's instruction, and the runway was visible to the crew due to good
weather condition and sufficient visibility, the CAP probably intended
to have the F/O continue the approach. It is considered that the CAP
paid his attention outside to assess the aircraft position and the
descent flight path from the view of the runway and the CAP would have
instructed the F/O only to have the aircraft recover the normal glide
path. |
(10) Concerning override of the AP
The CAP (PNF) instructed the F/O (PF) repeatedly to push the
control wheel. There seem to be the following possibilities as to why
he did so:
The aircraft incorporates a supervisory override function which allows pilots to assist the AP by applying a force on the control wheel when capturing the Glide Slope, the Localizer or the VOR course. There seems to be a possibility that the crew's experience in using this function led to their mistaken belief that they could override the APs during all phases of approach. This could have led them to override the APs while in GO AROUND mode.
The hazard of overriding the elevator by operating the control wheel while the APs are engaged in GO AROUND mode is described as a "CAUTION" in the FCOM. The reason why the crew took actions which nevertheless resulted in an out-of-trim condition, is presumed to be that they had not properly understood the contents of these cautions, and of other related descriptions in the FCOM. As mentioned later, the fact that descriptions in the FCOM are not easy for pilots to understand, and functions to alert pilots of THS movement are not properly incorporated, probably affected this outcome as a background factor (Refer to 3.1.11.3 and 3.1.11).
(11) Concerning the CAP's remarks at 11 14:58
At 14:58, CAP (PNF) said," I, that LAND mode?". This may be
interpreted as follows:
(1) | At 14:12, CAP (PNF) instructed the F/O (PF), saying, "Disengage
it." (Disengagement of GO AROUND mode was very likely). | |
(2) |
Twice after this, the CAP (PNF) cautioned the F/O (PF)
that GO AROUND mode was still engaged. | |
(3) | CAP instructed the F/O (PF) repeatedly to push the
control wheel. | |
It is considered likely that the CAP said "I, that LAND mode?" in
puzzlement on realizing that the aircraft was still not adopting the
proper attitude for descent, in spite of his above-mentioned
instructions and cautions. |
(12) Concerning timing of control take-over
After the APs had been engaged, the F/O attempted to recover the
normal descent path, but could not maintain airspeed and aircraft
altitude to do so.
To deal with this situation, the F/O (PF) disengaged both APs at
14:49, saying "Sir, auto pilot disengaged."
At 14:51, the F/O (PF) reported to the CAP (PNF), saying "Sir, I still
cannot push it down, yeah", probably because the pitch angle was still
high, and the aircraft was still not responding to his actions. Again
at 15:02, the F/O (PF) reported, saying "Sir, throttle latched
again."
Until then, the CAP (PNF) appears not to have fully grasped the flight
situation. Hearing the F/O's (PF) report above, the CAP (PNF) seems
to have decided to take over the controls to deal with the unusual
situation. At 15:03, CAP took over the controls. However, even at
this point, the CAP (PF) still seems to have been unaware that the THS
was at the nose-up limit.
Although the CAP (PNF) would have been unable to experience directly
the unusually strong resistive force of the control wheel until he
took the controls, in view of the points described below, he could
still have recognized to some extent that an abnormal flight condition
had arisen.
(1) | GO-AROUND mode continued to be displayed on the FMA. | |
(2) | The CAP had earlier instructed the F/O to push the control wheel
and retard the thrust levers in order to regain the normal glide path.
However ,the aircraft did not respond as the CAP had intended when he
issued his instructions. | |
(3) | The CAP had had to give directions and cautions (such as item
02 above) to the F/O, one after another. This fact itself suggests
that the F/O must no longer have been in a condition to perform PF
duty adequately. |
However, it is considered that the CAP's situational awareness as
PlC for the flight was inadequate, control take-over was delayed, and
appropriate actions were not taken.
(13) Concerning GO AROUND after CAP took over controls
Immediately after the CAP took over the controls, he retarded the
thrust levers to reduce the power before calling "GO lever" at
15:11.
It is considered that when CAP took control, although he was aware of
an unusually strong resistive force on the control wheel, he still
intended to make a landing; so he pulled the thrust levers to try to
reduce the pitch angle which was increasing. However, judging that
the CAP was unable to stop the pitch angle (which was increasing in
nose-up direction), it is estimated that he gave up landing, uttering
"How come like this?", decided to go around and then called out "GO
LEVER" while increasing the thrust, which had earlier been reduced, to
full thrust.
In normal go-around procedure, PF calls "go around flap" as he
operates the GO lever, PNF moves the SLATS/FLAPS lever one step up,
and after calling "positive climb" PNF performs a gear up operation
following PF' 5 order.
In this case, however, the correct procedure was not followed as
stated. After "GO lever" was called, it took about seven (7) seconds
before initial movement of the SLATS/FLAPS lever in the retract
direction took place.
While the SLATS/FLAPS lever should be moved from 30/40 to 15/20, from
the CVR record it is considered possible that the lever was moved to
15/0 or even higher, to the 0/0, before being lowered again to the
15/15 position. The landing gears were left in the down position (See
attached Figure 27.).
(14) Concerning operations performed to deal with increasing pitch angle and steep climb
In a pitch-up side
out-of-trim condition with the THS at -l2.3° and the elevators at
9.9°, the alpha floor function was activated, suddenly increasing
the thrust and which caused a large pitch-up moment to be generated.
The pitch angle did not stop increasing despite the CAP's
(PF) efforts who, after taking the controls, pushed the control wheel
to the forward limit and retarded the thrust levers.
Around 15:04,
the aircraft which had, until that point, been descending, began to
climb from approx. 500 ft pressure altitude (approx. 360 ft radio
altitude).
When the CAP(PF) increased the thrust
again and called, "GO lever", the aircraft was climbing through
approx. 600 ft pressure altitude with pitch angle at 21.5°.
The
pitch angle was further increased by a large pitch-up moment generated
by the increase of thrust under the pitch-up side out-of-trim
condition.
Speed began to decrease from 137 kt around 15:08.
It is considered that the CAP (PF) continued
to push the control wheel fully to reduce the pitch angle, and
intermittently operated the pitch trim control switch in the pitch
down direction, as indicated by the slow return of the THS from the
limit angle of -12.3° to -l0.9° by 15:19.
(Intermittent use of the
switch does not generate the "Whooler" tone.)
Thereafter, the THS
moved again from -10.9° at 15:21 to -7.4° at 15:27.
It is considered
possible that the alpha trim function activated because the AOA at
15:23 was approx. 18°, which exceeded the threshold angle of
17° for SLATS/FLAPS 15/20 and 15/15 configurations.
It was not determined
whether or not the manual trim had been operated during the above
period.
During the period from 15:27 to 15:33, the THS remained at
-7.4°
The CAP (PF) operated the pitch-trim only intermittently
during the go around. Consequently, it is considered that he was not
aware of the THS state.
There are three feasible
ways to reduce increasing pitch angle: to push the control wheel, to
regain trim, and to reduce the thrust. Under the conditions of steep
climb and continued decrease of speed, it seems that the CAP(PF)
hesitated to reduce the thrust.
However, at this point of time, when
the speed had decreased to 115 kts., the pitch angle had increased to
an abnormal 40.3°, it is considered that the CAP (PF) retarded the
thrust levers to reduce pitch angle.
At approximately 15:23 No.1
thrust lever was retarded to a position near idle and No.2 thrust
lever was retarded slightly. This is probably because, although the
CAP was hastily attempting to retard the thrust levers in an effort to
correct the aircraft attitude which continued to climb steeply, the
CAP's (PF) hand came off the thrust levers at the above-mentioned
position while continuing to push the control wheel with the
aircraft's steep nose-up attitude.
Around 14:27, the thrust levers
were moved to a position close to full thrust. This seemed to result
from the fact that either the CAP or the F/O pushed the thrust levers
forward in an attempt to recover lost speed.
It is also presumed
that the aircraft's nose-up pitching moment was further increased as a
result of the SLATS/FLAPS retracting from 30/40 to 15/15.
(15) Concerning crew coordination between the CAP and the F/O (See Appendix 2-1)
The F/O must have perceived the abnormally
strong resistive force of the control wheel, but he, who was under
high stress from the following factors, probably delayed reporting the
situation properly to the CAP:
At
1114:17, the aircraft deviated more than a dot upward from the glide
slope, and speed decreased to less than -5 Kts. from the VAPP of 140
KCAS as the aircraft continued approach. Despite this, the CAP did
not call out these facts as PNF. |
(16) Concerning the tones of MASTER CAUTION record on CVR.
There is a possibility that audible
tones of MASTER CAUTION (SINGLE CHIME) recorded on CVR at 1115:23,
15:28 and 15:31 were set off respectively by the tripping of the yaw
damper levers, pitch trim levers and ATS lever. | |
These CAUTIONs were
triggered because the input sensor data were judged as "INVALID" and
the systems relating to the above mentioned levers were
disconnected. | |
Because the aircraft's attitude and speed changed
rapidly during this phase of the flight, the possibility that the
MASTER CAUTIONs were generated by a different cause cannot be ruled
out. | |
However, if the conditions on which these CAUTIONs sounded ,
the relations among these occurrences around the time when they
sounded, and the analysis of the sound spectrum of the CVR recordings
are considered together, it would be highly possible that these
CAUTIONs are the same as the ones described at each of the times in
paragraph 3.1.2.1. |
As described in 3.1.1, it is estimated that the CVR and DFDR stopped recording around 1115:45. This was probably caused by the breaking of cables on impact. The time of the crash is estimated to be around 1115:45 (when the CVR and DFDR stopped recording).
From the DFDR records, it is estimated that the aircraft stalled, then 4escended steeply with wildly changing roll angle, and impacted the ground.
The spot where the aircraft hit the ground was an unpaved, flat landing area. There were marks left on the ground surface that clearly identified those portions of the aircraft which had hit the ground. From the shapes of the marks and these positional relationships as well as the condition of destroyed landing gears, it is inferred that on impact, the aircraft was in a somewhat left-wing down, nose-up attitude, and was in an almost level attitude.
The broken nose and main landing gear were investigated in order to analyze the conditions of the landing gear, the aircraft attitude, and other associated conditions of the aircraft at the
time of the crash.
All of the broken landing gears had signs of compressed oleo struts with buckled cylinders, which implies that the gears received an upward thrust, and so that the aircraft had impacted the ground with all landing gears extended.
The rear bogey beam of the LH main gear, which presumably touched the ground first, was sheared off in a ring shape at a relatively thin portion beside the strut attaching part. The rear inner wheel (with tire still inflated) of the LH main gear and the accompanying brake assembly, were flung away furthest to a point approximately 190 meters from the point of impact. It seems that this occurred because of a rupture that occurred at the moment of impact, when the kinetic energy was greatest and its loss was minimum, and also by a high rebound force brought about by the tire.
The damage to the two (2) front tires of the LH main gear was extensive, with outer tires burnt and inner tire burst owing to impact. An assumption from these conditions is that breakage occurred at the front and rear of the bogey beam, with subsequent impact transmitted directly from the ground to the strut. The direction of lacerations on the tires suggested that they skidded to the right.
The crash process from when the aircraft first hit the ground to when it was destroyed is estimated to be as follows:
(1) |
The LH main gear of the aircraft
impacted the ground first, and at this point of time, there were no
other parts in contact with the ground. |
Compared with the wheelbase
of the aircraft, the measurement between the scars on the ground was
greater. This implies that the aircraft was moving forward in a
slightly nose-up attitude. | |
At this point in time, the aircraft's
magnetic heading was approximately 15 degrees (015°)
and its side-skid
angle was approximately seven degrees (7°) to the right,
judging from
the aircraft's attitude, that was almost level, and the direction of
motion of the aircraft deduced from the marks left on the ground. | |
Since the LH main gear impacted the ground first, the aircraft's began
to turn counterclockwise as viewed from above. | |
(2) |
The RH main
gear impacted the ground a little later than the LH main gear. |
The
fact that the ground scars of both main gears were not long in
comparison with the track of the wheels suggests that the aircraft was
descending at a steep flight path angle. The pitch angle at this time
was approximately four degrees (4°) nose-up, as calculated from the
geometrical characteristics of the aircraft, the conditions of the
broken LH main gear, and the position of the nose gear. | |
(3) |
At
the moment the LH engine impacted the ground (receiving the strongest
shock), the RH |
engine was beginning to receive the
impact from the ground. Both the main gears were being destroyed in
that while. | |
The roll angle at this time was approximately three
degrees (3°) to the left as determined from the positions of
both main gears, nose gear, and LH engine. | |
(4) |
By the time the nose landing
gear impacted the ground, and was under maximum shock, both main gears
had already been destroyed and the LH engine was in the process of
destruction. |
(5) |
At the above point in time, the LH wing-tip also
hit the ground. |
Judging from the positions where the marks of the LH
wing tip and RH engine were found, all the landing gears were
destroyed and the bottom of fuselage started breaking. The aircraft
received an additional counter-clockwise moment after touching the
ground and the entire airframe was distorted. | |
The recovered LH
wing-tip had a deformation showing an impact it had received from
contact with the ground at its lower, slightly inboard section. On
the other hand, the LH wing tip was damaged on its upper part,
indicating that it was damaged when the RH wing was destroyed. | |
(6) |
After the LH wing-tip had been destroyed, the LH flap track
touched the ground. Destruction of the fuselage progressed to the
lower part of the floor, and shortly afterwards, the horizontal
stabilizer was flung onto the ground almost in a level attitude. |
The
direction of the scratch marks left on the lower access panel of the
THS corresponds roughly to the direction in which the debris were
strewn (22 degrees (022°) in magnetic heading). | |
From
extrapolation using the DFDR records, the trajectory angle at the time
of impact was estimated to be approximately 32°. |
After the aircraft had impacted against the ground, the major parts of the wreckage are estimated to have been in the conditions described below.
From the scattered condition of wreckage, it is estimated that the momentum vector of the aircraft in the level plane when it crashed was approximately 22 degrees (022°) from magnetic north and approximately 42 degrees (42°) to the right of the centerline of the runway 34.
(1) |
The LH engine, having dropped
from the wing pylon, tumbled forward; the lower skin of the aft
fuselage remained in the vicinity of the spot where it had first
contacted the ground, and the horizontal tail plane and APU
compartment were ruptured and had separated. |
(2) |
The outer flap,
center flap, and outer wing of the LH wing were ruptured and had
separated from the wing. |
(3) |
The outer flap,
center flap, inner flap, spoiler, outer wing and other components on
the
RH wing were ruptured and had separated from the wing, and were
strewn as far as the irrigation ditch. |
(4) |
The upper portions of
the forward and aft fuselage sections, along with the portion of wing
that remained attached to them, tumbled to the vicinity of the
irrigation ditch, together with the ruptured and separated vertical
tail plane and upper portion of the aft fuselage, all in broken
state. |
(5) |
The cargo loaded on board was scattered in the area
between the spot where the aircraft hit the ground and the vicinity of
the irrigation ditch, and almost all ruptured seats were found near
the irrigation ditch. |
(6) |
The fuel that had leaked from the broken
LH wing when the aircraft crashed into the ground splashed over the
area from the vicinity of the spot where the LH wing first hit the
ground to where the center of the wing had come to rest, and fuel from
the RH wing was scattered widely, together with debris of the RH wing,
as far as the vicinity of the irrigation ditch. |
It is estimated
that among the wreckage strewn forward, by the forward-acting inertial
force generated when the aircraft crashed, were items such as the
fuselage section aft of the central wing section, functional
components, cabin furnishings, seats, and cargo burned when the fuel
ignited, and were destroyed by expanding fire. |
Investigation of the dismantled engines revealed that damage to components of both engines were indicative of their rapid destruction. Rotors blades were torn and deformed in the direction opposite to that of rotation. All these conditions support the assumption that the engines had been running at high speed until the aircraft crashed.
The data recorded in all the channels of both FADECs show that surges occurred in both engines, indicating a sudden drop of combustion chamber pressure during the flight.
Also, engine data recorded by the DFDR show that the engine pressure ratio, fuel flow rate, and high-pressure shaft rotating speed dropped for short periods at 1115:31 for the No.1 engine and at 1115:32 for the No.2 engine, to values lower than those that should normally result in response to the thrust lever operation performed. This could have been due to the FADEC counteracting the engine surge. Subsequently these engine parameters returned rapidly to values that normally correspond to the thrust lever movements, and no abnormalities caused by surges of the engines were subsequently detected.
When engine surging occurs, flames sometimes shoot out from the front and rear of the engines. Both engines may therefore have emitted light as the aircraft fell into an abnormal
condition during stall.
It is estimated that the engine surge which occurred when the aircraft fell into a stall condition was due to a phenomenon called "inlet distortion" in which uniform air flow through the engine air inlets is not available owing to a high AOA.
It is estimated that the AOA at this point of time was far greater than the range for normal operation, exceeding the engine air intake airflow angle limit permitted for the aircraft.
The memories of one FAC, one FMC, one SGU-EFIS, two SGU-ECAMs, one FWC, two ADCs, three IRUs, two GCUs, and one ILS receiver could be read out, but there nothing was recorded that might have been of relevance to the accident.
Of the components recovered from the crash site, 54 items (128 Units) including the AP pitch actuator, elevator actuators, trim actuator gear box, and center pedestal and so on, were analyzed by means of disassembly and other methods. Nothing abnormal was found except the damage inflicted at the time of the accident.
As shown in 2.15.2, IRS mode selector No.3 was in the NAV position, while the No.1 and No.2 selectors were in the OFF and ATT positions, respectively. The IRS is an essential system for engaging the APs, and the DFDR records indicate that both AP No.1 and No.2 were engaged. Also after that, the CVR records did not contain any data that suggests failure of the IRS s, and further, there were no evidence showing changeover of the selector in the Left side Instrument Switchings record. These facts imply that the No.1 and No.2 IRS mode selectors were moved by the impact at the time of ground impact, or later.
(1) SLATS/FLAPS positions
By comparing the screw jack nut
positions of the SLATS/FLAPS actuators of an aircraft of the same type
with those of the crashed aircraft, the nuts of the crashed aircraft
were to be at the positions corresponding to 15/15.
These positions
are almost in agreement with the last SLATS/FLAPS angles of
17.05°/8.25°
(15/15 position) recorded on the DFDR.
Also, the
shaft of the broken SLATS/FLAPS command sensor unit was found seized
up at the
15/15 position.
Judging from the above
findings, it seems that the SLATS/FLAPS lever position of 15/20
shown in paragraph(2), Section 2.15.2, was a result of a movement that
might have occurred as
a result of impact, or some time afterward.
(2) THS angle
The THS angle was determined to have been
approximately 8° as a result of a comparison made between the THS screw
jack nut position of the crashed aircraft and that of an aircraft of
the same type. This angle roughly agrees with the last THS angle of
-7.4° recorded on the DFDR.
It was also found that the pitch trim
control cable system was broken.
The conclusion from the above is
that the THS position indicator reading of -9.4° / 9.5° shown in
paragraph(2), Section 2.15.2, is a result of a movement in the
indicator that might have occurred at impact or thereafter.
(1) | Analysis of data recorded on channels 2 and 3 of the CVR, could not determine where the CAP and F/O had been seated, since the voices and sound records, including radio commutations on channel 2 (on the F/O's seat side) are exactly the same as that on channel 3 (on CAP's seat side), owing to the cockpit intercom communication system. |
(2) | From the record of the CAP's call out, "SHOULDER HARNESSES" (1100:05), to confirm the wearing of the shoulder harnesses as he read the approach checklist, the record of the F/O's response, "FASTEN RIGHT", and the record of the CAP's confirmation of approach check list completion, "OK, FASTEN LEFT, APPROACH CHECKLIST COMPLETED" (1105:05), on the CVR, it is estimated that the CAP was seated in the left seat and the F/O in the right seat. |
(3) | From the conversation between the CAP and F/O, recorded on CVR, about control of a light, it is recognized that the CAP was adjusting a light (refer to attached Figure 23). |
Of the adjustable lights, if the one that the CAP (PNF) was adjusting was the captain and center instrument light, or the main instrument panel flood light, it is considered that the CAP was seated in the left seat (the adjusting knobs of these lights are located at the left end of the instrument panel, on the same side as the left-hand seat). | |
However, if the light which the CAP (PNF) was controlling was either the glare shield light, pedestal and overhead panel light, or the dome light, the adjusting knobs of these lights could be operated from either the right or left seat. | |
As inferred from the above, it is therefore not possible to determine which seat the CAP was occupying. |
(1) | The recovered seat wreckage had damage marks caused at the time of the ground impact. Analysis of the seat-setting positions from these marks is as follows: for the left seat (CAP's seat), the vertical position was set approx. 70 mm above the lowest position, and its longitudinal position was near the foremost position, whereas for the right seat (F/O's seat), the vertical position was set approx. 30 mm above the lowest position, and the longitudinal position was set approx. 33 mm rearward from the foremost position. |
As inferred from these settings, the right seat was set approx. 40 mm lower than, and approx. 33 mm rearward of the left seat. Since the crew positions are adjusted by means of an eye locator, such that the eye levels of both the right and left seat occupants will be about equal, it is considered that the person in the right seat was taller than the one in the left seat. | |
(2) | According to the airman medical certificate, the CAP was 162.5cm tall and the F/O 178.1cm tall. From this data, and the damage marks to the seats discussed in (1), it is estimated that the CAP was in the left seat and the F/O in the right seat. |
From the implication of the CVR record concerning the wearing of the shoulder harnesses, and by comparison of the vertical and longitudinal positions of both seats estimated from the damage marks to the seat wreckage, as described in sections 3.1.7.1 and 3.1.7.2, it is considered that the CAP and the F/O were seated in their formal positions: the CAP in the left seat, and the F/O in the right seat.
The number of survivors of this accident was seven (7), all being seriously injured. As noted in section 2.12.2, 16 passengers were taken to several hospitals by rescue workers.
(1) | Among passengers hospitalized, six (6) persons were found dead on
arrival. The cause of death of four (4) of the six (6) was whole body
contusion and fractures; the other two (2)
died of whole body contusion and thermal injuries. |
It is estimated that four out of the six (6) were seated in the forward section of the cabin and the other two (2) in the aft section. | |
(2) | Three (3) out of the (10)
seriously injured passengers died on April 27, April 28, and May 1,
respectively, at the hospitals to which they had been admitted. The
cause of death of these three (3) was whole body contusion and
fractures. |
The estimated seat assignment for two (2) of the three
(3) was in the forward section of the cabin and one (1) in the aft
section. |
(3) | The remaining seven (7) seriously
injured were diagnosed as suffering from traumatism and various
external injuries, primarily bone fractures. |
All of these seven (7)
passengers were seated in the forward section of the cabin, in front
of the wings. |
According to the post-mortem report, the cause of death of those passengers who died before hospitalization was determined to be whole body contusion, fractures, and thermal injuries.
The positions where the passengers suffering whole body contusion and fractures were seated extended over the whole cabin area, from the front to the rear of the cabin, while thermal injury was noted in many of the passengers who are estimated to have been seated behind the main wing where the fire started.
The remains of CAP, F/O, and purser were stored in the hangar after the accident, and underwent autopsies at different colleges. During the autopsies, samples were collected from the remains, and taken to the Scientific Investigation Labs of Aichi Prefectural Police Headquarters, where they were stored in refrigeration. On the following day, alcohol reaction tests were performed at the Labs. The results are summarized below.
Time elapsed after death and before sample was taken | Sample | Ethanol concentration | |
CAP | Approx. 24 to 25 hours | Pleural fluid | 13 mg/ 100 ml |
F/O | Approx. 19 hours | Pleural fluid | 55 mg/ 100 ml |
Purser | Approx. 19 hours | Blood in heart | Not detected |
Ethanol was detected in the samples from the remains of the CAP and the F/O, which is considered to be due to one or more of the following three causes.
It is also considered that two or three of the following causes were combined.
(1) | Post-mortem ethanol production |
(2) | Alcohol ingestion before death |
(3) | Mixture with alcoholic drinks on board |
Each of the three causes were analyzed as described in the following sections.
According to legal medical documents, there are confirmed cases where ethanol has been
detected in the body of a person who never ingested any alcohol before death. It is understood that progress in decomposition of the body after death results in microbial fermentation, which produces ethanol.
There is a possibility that the ethanol detected in the remains of the CAP and the F/O was due to a post-mortem ethanol production for the following reasons:
(1) | The remains of the cockpit crew were stored in
a hangar after the accident, and approximately 18 to 22 hours elapsed
before they underwent autopsies. During this period, special
measures, such as placing the remains in refrigerated storage, were
not taken. |
The lowest and highest atmospheric temperatures at Nagoya Airport area
during this period were approximately 1 0°C and 23°C,
respectively. The temperatures in the hangar where the remains were
kept is assumed to have been somewhat higher than the above-mentioned
temperatures. | |
Furthermore, it was noted that the remains of CAP and F/O had deep
open wounds. In particular, the body of F/O was significantly
damaged. | |
The long time interval from occurrence of the accident to the
autopsies, the environmental temperatures, and the existence of open
wounds are considered to satisfy the conditions for post-mortem
ethanol production. | |
(2) |
The concentrations of ethanol detected in the bodies of the CAP and
the F/O were 13 mg/1 00 ml and 55 mg/i 00 ml respectively; these
concentrations are considered to be comparable with those normally
detected as a result of post-mortem production. |
(3) | Regarding the difference in concentration between the ethanol
found in the body of the CAP and that in the body of the F/O, when the
difference in temperature resulting from the difference in location
within the same hangar and the difference in severity of open wounds
between them are taken into account, the variation in concentration is
considered to be within a conceivable range. On the other hand,
ethanol was not detected in the pursers body which had a few open
wounds. |
Collected samples from the bodies of the CAP and the F/O in this case consisted only of pleural fluids, probably because damage to the bodies was extremely extensive. If the crew drank any alcohol before death, ethanol may have been detected in their pleural fluids (as ethanol in the blood is absorbed into other internal organs some time after alcohol is ingested). From the fact that the open wounds of the bodies of both the CAP and F/O were extensive, it is considered possible that blood became mixed with their pleural fluids.
If this is the case, the concentration of ethanol detected in the samples should be the concentration of ethanol produced post-mortem described in section 3.1.9.1 plus the concentration of ethanol resulting from alcoholic ingestion, but the possibility of alcohol ingestion before death and the extent thereof could not be determined.
Adjacent to the cockpit and behind the F/O's seat, a galley (No.1 galley, see attached Figure 26) was located in which liquors (about 40 bottles of whiskey and other liquors) were stored for passenger service. Also on board were bottles of alcoholic liquor carried by passengers.
It seems possible that destruction of the partition between the cockpit and galley by the impact caused liquors and other alcoholic drinks from broken bottles to be scattered over the bodies of the crew (who had open wounds). However, it could not be confirmed.
China Airlines has an Operations Policy Manual and an Air Crew Manning and Dispatch Manual that were prepared according to the requirements stipulated by the Taiwanese civil aviation authorities, and operate their aircraft in compliance with those manuals.
(1) | Qualifications for Flight Crew |
According to an Operations Policy Manual, the flight crew shall
consist of personnel of good character, clear-cut features, and
sufficient technical knowledge, and shall in addition satis~ the
following conditions. | |
It is recognized that the CAP and F/O of the aircraft held valid licenses and satisfied the required number of hours' flight experience. | |
(1) CAP | |
| |
(2) F/O
| |
(2) | Requirements for Flying Aircraft by F/O in
Revenue Flights |
According to "AIR CREW MANNING AND DISPATCH MANUAL", requirements for |
flying aircraft by F/O in revenue flights are stipulated as
follows. (item (1) through (4) ) | |
(1)
China Airlines shall have F/Os fly a certain aircraft type in take-off
and landing phases at least three times every three months to maintain
their flying skills. | |
(2)
When an F/O is to control an aircraft type in a revenue flight, the
F/O shall be seated in the right seat. | |
(3) When an F/O is to control an aircraft type in a revenue flight,
the CAP shall strictly
supervise the F/O's operation, shall assume all responsibilities for
safety, and shall observe the following:
| |
(4) When flying, if 1) the weather conditions do not meet VMC criteria,
2) a fault occurs in the aircraft, 3) a clearance given by ATC is
inappropriate, 4) the F/O carries out a procedure that exceeds the
safety limits of the aircraft, or 5) if an emergency arises, the CAP,
in the interest of safety, shall make a quick decision to take
control. | |
It is recognized that items O,(c) and (c)-a, b and c above were
satisfied in this case, i.e., that the F/O was flying the aircraft in
revenue flight. | |
Considering item (c) above, whether the CAP kept his hands and feet in
the appropriate positions during the approach and landing phases could
not be determined. However, from the CVR record, it is recognized
that he took over the controls to deal with the abnormal situation,
saying "I have got it" at 1115:03. | |
Concerning item (4) above, as described in Paragraph 3.1 .2.2.(12), it is considered that the CAP's judgment situational awareness was inadequate, and that he was delayed in taking over the controls. | |
(3) | Utilization of Operation Technical Reports |
China Airlines used the technical report on the incident of the A3 10 aircraft that had occurred on February 11, 1991 in Moscow for the training of the crew members concerned. However, there are no records indicating that they used the reports on other cases for training purposes. The CAP and F/O involved in the accident did not attend the training that utilized the above technical report, as at the time they were not yet been assigned to A300-600R aircraft. |
(1) Training
China Airlines has established a training program according to the requirements stipulated by Taiwanese civil aviation authorities to conduct the following training courses in the classroom, simulator, and aircraft.
The CAP and F/O are recognized to have finished the training established by China Airlines. In the case of the A300-600R aircraft training program, the company basically employs the syllabus established by Airbus Industrie, the manufacturers of the aircraft, as their syllabus with the training standard times set themselves.
(1) | New qualification acquisition training | |
Training performed to give experience, knowledge, and skill required
for obtaining flight crew qualifications. | ||
(2) | Promotion training Training performed to give experience,
knowledge, and skill required for obtaining higher level flight crew
qualifications. | |
(3) | Type transfer training | |
Training performed for flight crew who are to serve in an aircraft of
a type different from the one in which they are currently serving or
in which they served in the past to give experience, knowledge, and
skill required for obtaining identical class flight crew
qualifications. | ||
(3) | Periodic training | |
Training performed periodically for flight crew to maintain and
improve their knowledge and skill. |
(2) Simulator training
(1) |
China Airlines did not have simulators for the A300-600R aircraft.
Therefore, they conducted simulator training for the said aircraft
type by using simulators owned by Thai International Airways of
Thailand and Aeroformation of France (China Airlines contracted part
of pilot training to Airbus Industrie, and Airbus Industrie
subcontracted this to Aeroformation.). |
(2) |
The CAP underwent simulator training for the A300-600 aircraft type in
the Thai International Airways' simulator approved by the Thai
aviation authorities. The F/O underwent this same training for the
said aircraft type in the Aeroformation simulator approved by the
French aviation authorities, and periodically in the Thai
International Airways' simulator. |
(3) |
The simulator training manual used by China Airlines was prepared by
Aeroformation of France. However, it had not been updated. |
(4) | When the F/O underwent simulator training in October through November, 1992 in the Aeroformation simulator, a item of" GO-AROUND DEMONSTRATE AP MISUSE IN GO-AROUND "was included in its check sheet which the instructor used. |
A mark "+" was placed in the box indicating
completion of the item. Airbus Industrie said that the item was added
after the incident which had occurred in Moscow airport in February
1991. | |
However a check sheet, which the F/O was previously given as a
part of training materials by Aeroformation before training, was not
yet revised and did not contain the above item. | |
But how the F/O
underwent training for the item could not be clarified. | |
When the CAP
underwent the training in June through July, 1992 in the Thai
International Airways' simulator, the check sheet, which China
Airlines had obtained, was used. But this check sheet was not revised
and did not contain the above item. | |
(5) | Concerning that Airbus Indstrie did not provide China Airline with up-to-date training materials, it is considered that the agreement on dealing with up-to-date training materials was not made clearly between the two companies which had contracted the crew training. |
(6) |
According to French and Taiwanese persons concerned, the Thai
International Airways simulator does not simulate the AP overriding
function in GO AROUND mode for the A300-600R aircraft's AP, but
whether this had any bearing on the accident could not be determined. |
(3) AFS Training
(1) |
The descriptions in FCOM for the AFS are not easy for crews to understand. |
(2) |
The crew was not given sufficient technical information with regard to
similar incidents. |
(3) | Up-to-date training materials were not properly obtained. |
(4) |
CVR transcripts show that crew understanding of the AFS was
probably not sufficient. |
From the above items it is concluded that the training required to understand the sophisticated and complicated AFS was insufficient.
Service Bulletins (hereinafter referred to as "SBs") are issued by the manufacturers to notify each operator of the inspection and modification to aircraft and their equipment.
SBs are generally divided into four compliance categories: Mandatory, Recommended, Desirable, and Optional. Upon receipt of an SB, operators, referring to the compliance category described on the SB, determine whether or not it applies to their airplanes and, if so, how they should implement it.
Mandatory SBs are usually implemented on earliest possible occasion. If the SB is "Recommended" or any of the remaining categories, operators plan to implement it on the most suitable occasion, taking into consideration their operational experience, maintenance schedules, and type of operation.
In China Airlines, the Maintenance Headquarters first receive SBs, and then the engineers belonging to the Chief Engineer Office determine the way to implement each of the SBs as well as the applicable airplane numbers after evaluating and examining it. The determined results are entered in a form called TIPS (Technical Instruction Processing Sheet) which is then forwarded to the Department of Maintenance Control after being examined by the Department of Quality Assurance. The SBs are implemented under the supervision of the Department of Maintenance Control.
SB A300-22-6021 issued by Airbus Industrie dated June 24, 1993 with compliance "Recommended" specified, concerned a modification to the AFS, which disengages the AP when a force in excess of 15kgf is applied to the control wheel in pitch axis during a flight in the GO AROUND mode above radio altitude 400 ft (See appendix 2.). To implement this SB, it was necessary to modify the two FCCs on each aircraft to which it applied.
According to China Airlines, the actions they took after receipt of the SB were as follows:
At the beginning as stated before, China Airlines adopted the SB A300-22-602 1, but planned to accomplish the modifications at the time when FCCs needed repair (because the modification was not considered urgent). Since no FCCs had been sent to Sextant Singapore for repair before the Nagoya accident, the modifications in accordance with the SB A300-22-6021 were not made.
Concerning the A300-600, it was possible for a pilot to override the elevators while the AP was controlling the THS in GO AROUND mode and LAND mode. Therefore, two control inputs for two different objectives could be allowed simultaneously in the pitch axis. The aircraft was not equipped with a warning device which would alert the pilot to two simultaneous control inputs. Such a design might have contributed to the accident as one of the factors of the abnormal out-of-trim.
In order to verify the status of the THS, a computer simulation was conducted to demonstrate THS movement using the recorded parameters in DFDR such as airspeed, attitude, etc. The analysis revealed that the calculated THS movement history showed good correlation with the recorded THS data. From the analysis, it is recognized that FAC and FCC were functioning normally per design concerning with THS movement.
(1) |
With regard to the A300-600 aircraft incident of March 1, 1985
that involved an out-of-trim condition triggered by the switching of
AP mode to ALT HOLD mode, Airbus Industrie established Mod.7 187 in
order to prevent the recurrence of similar incidents, and on March 18,
1988 it was approved by DGAC. |
The Mod. 7187 was to add a function to
allow AP disengagement by applying a 1 5Kgf force on the control wheel
in pitch axis in modes except LAND track (below 400ft radio altitude)
and GO AROUND mode. | |
After that, Mod. 7187 was included in SB
A300-22-6009 dated June 1, 1989, but the SB did not contain any
mention of the Mod.71 87. | |
After that, in view of further incidents
which involving out-of-trim conditions triggered by AP mode switching
to GO AROUND mode -- on the A300-B4-203FF aircraft at Helsinki Airport
on January 9, 1989 and on the A3 10 aircraft at Moscow Airport on
February 11, 1991 -- Airbus Industrie issued SB A300-22-6021 dated
June 24, 1993 which recommended operators to accomplish a modification
to the APS, as a measure against recurrence of similar incidents,
namely to introduce a function that disengages the AP when a force
greater than 15kgf is applied on the control wheel in pitch axis at a
radio altitude higher than 400 ft in GO AROUND mode. | |
(2) |
Although the causes which triggered the above incidents are
different, all the incidents were similar in that the operation of the
control wheel by the crew and operation of the AFS conflicted with
each other, the THS ended up in an out-of-trim condition, and the crew
had to deal with a rapidly changing aircraft attitude, without having
time to grasp the full extent of the situation. |
Such serious
incidents occurred in March 1985, January 1989, and in February 1991
respectively. | |
Airbus Industrie informed operators of the summary of
the these incidents, but did not present a systematic explanation on
the technical background sufficiently. | |
(3) |
As described in (1), three to four years elapsed before, in
response to the incidents, Airbus Industrie introduced the
modifications to the AFS. Considering the importance of the
incidents, it is considered that the modifications were not introduced
promptly enough. |
The system to make acceptance of modification available to operators
was completed at the FCC manufacturer in September, 1993 after Airbus
Industrie issued the SB on June 24, 1993, as mentioned in section
3.1.10.3. | |
(4) | The China Airlines' A300-622R B-1 816 aircraft which crashed at Nagoya Airport on April 26, 1994, had incorporated Mod.7 187 when manufactured, and implementation of SB A300-22-602 1 was planned. However this had not been done by the time the accident occurred. |
It is considered that in the accident at Nagoya Airport, activation of the GO lever by the crew changed the mode to GO-AROUND mode, and since the crew later engaged the APs, the control wheel push-down operation by the crew, who seemed to have intended to continue approach, conflicted with the motion of the THS controlled by the AFS, resulting in an abnormal out-of4rim condition. If the modification prescribed in SB A300-22-602 1 had been incorporated, it is considered that the APs would have been disengaged under a |
force greater than 15kgf applied at the control wheel in the nose-down
direction, preventing the aircraft from entering such an abnormal
situation. | |
However, China Airlines who received the SB judged its accomplishment
not urgent and decided to implement the modification on an occasion
when their FCC(s) needed repair. | |
Since operators had hardly grasped and understood the technical
background and detailed information with regard to the three serious
incidents described in the items of (1) and (2) above, it is
considered that this decision was affected considerably by the fact
that the SB was issued as "Recommended", and not "Mandatory", and the
reasons and technical background for issuance of the SB were not
explained clearly and in detail. | |
(5) |
In view of the significance of those three incidents, it is
considered proper that the French airworthiness authorities pertaining
to aircraft design and manufacture, at an earlier stage, should have
urged Airbus Industrie to establish the modification promptly to
preclude the recurrence of similar incidents, and issued an
airworthiness directive so that each operator could implement promptly
the SB pertaining to the modification. It is also considered
necessary for the French airworthiness authorities to have requested
Airbus Industrie to provide each operator with technical information
describing each incident systematically. |
(1) |
Revision of FCOM Based on Mod.7187 (See Appendix 2-2 and 2-3) |
After the incident involving an A300-600 aircraft on March 1, 1985,
Mod.7187 (rearranged into SB A300-22-6009 in June 1989) was
established on March 18, 1988, introducing a function allowing AP
disengagement in pitch axis in modes except LAND track (below 400ft
radio altitude ) and GO AROUND mode. | |
The condition of "LAND mode" was not clearly described in the FCOM
issued in June 1988. It is ambiguous whether this meant a phase after
LAND mode was selected on the FCU or a phase when "LAND mode" is
displayed on FMA (LAND track mode). However, when SB A300-22-602 1
dated June 24, 1993 (addition of function of allowing a pilot input in
pitch axis to disengage the AP above 400ft radio altitude in GO AROUND
mode) was implemented, the description in the FCOM concerning the
above mentioned "LAND mode" was revised and clarified such that LAND
mode meant a phase when "LAND mode" is displayed on the FMA. | |
(2) | Addition of CAUTION (See Appendix 2-2 and 2-4) |
After the incident involving an A300B4-203FF aircraft at Helsinki
Airport on January 9, 1989, FCOM 1.03.64 P 3/4 and 2.02.03 P 1 were
revised in January, 1991, adding a CAUTION against a hazardous
out-of4rim condition that may lead the hazardous situation if the AP
is overridden in pitch direction during the LAND and GO-AROUND modes. | |
The FCOM describes that this override was concerned in order to
protect the pilot against AP abnormal behavior. On the other hand the
CAUTION in the FCOM prescribes that pilots are prohibited from
overriding the AP when it operates normally. |
Therefore, pilots may be confused and may receive two contradictory
meanings, such as recommendation and prohibition. For example, if a
pilot had suspected that the APs were malfunctioning, he might miss
taking proper action because no criterion had been written as to the
situations in which one should override. Accordingly, the technical
information, examples of possible situations, and the corresponding
confirmation and operation procedures should be written in the FCQM
systematically in order to encourage crews' further understanding of
the AP overriding function. | |
(3) |
FCOM 1.03.67 P-8 REV 17 (A3 1 0/A300-600) (See Appendix 2-3) |
| |
(4) | Notice to each operator issued by Airbus Industrie after the Accident in Nagoya |
After the accident involving a CAL Flight 140 at Nagoya Airport, which occurred on April 26, 1994, Airbus faxed all A300/3 10 and A300-600 aircraft operators cautionary information to be applied when a pilot moves the elevators in conflict with the APs while |
When the AP is in CMD, the AP actuators move the roll, pitch, and yaw control surfaces in response to commands from the FCC. The THS moves according to commands from the FAC.
The override function mechanically disconnects the AP actuator from the control surface and allows the pilot to manually control the aircraft by applying a force greater than a threshold on the control wheel or rudder pedals. When the force applied to the control wheel or rudder pedal is released, the AP actuators are reconnected to the corresponding control surfaces. However, the THS remains under control of the AP even while the AP is being overridden and continues to operate as commanded by the AP.
Airbus Industrie define the AP override function in their FCOM and FCOM Bulletin as a safety device to allow the flight crew to regain control from the APs in the event of AP anomalies. Airbus Industrie also recommend in the above bulletin that the pilot should disconnect the APs immediately, upon suspicion of any abnormal aircraft behavior when AP is in CMI) (See Appendix 2-4 and 4.).
When the AP is in CMD, if the pilot overrides the AP's pitch command for some reason, the AP activates the auto-trim function and moves the THS so as to maintain the aircraft on the scheduled flight path. If the pilot disengages the AP without noticing this, the aircraft is left in an out-of-trim situation which might be hazardous if not trimmed back (See Appendix 2-6.).
In the case of a post SB A300-22-6021 aircraft, if the crew carry out an operation to hold the control wheel in an effort to decrease an excessive pitch angle at a radio altitude lower than 400 ft during a go-around started from a low altitude, the result will be the same as an AP override operation, causing the THS to move toward the nose-up direction. If the crew is not aware of the THS movement and does not make a trim-back operation, the aircraft could enter an out-of-trim situation, which is potentially hazardous.
As the aircraft continued descent in an out-of-trim condition, the pitch angle and the angle of attack (AOA) increased. The AOA exceeded the threshold angle of 11.5 degrees, corresponding to SLATS/FLAPS 30/40, while crossing approximately 550 ft pressure altitude at 14:57. The alpha floor function was activated, increasing power. Although, immediately after this, the thrust was reduced for a while, the go-around thrust was set again, and a rapid increase of the pitch angle continued.
In the case of this accident, the Alpha Floor function -- a safety device which is designed essentially to prevent stall and to protect aircraft within the flight envelop -- activated and increased the engine thrust when the THS was in full nose-up position. This generated a pitch up moment. Immediately after this, although the thrust was manually reduced for a short period, the pitch angle increased by 9.5°, up to 18.0°. It is considered that the automatic increase of the thrust and the accompanying increase in pitch angle resulted in a narrowing range of selection for subsequent recovery operations, and a reduction in the time allowance for such operations.
It is considered probable that, after the CAP called "GO lever" at 1115:11, the alpha trim function came into operation about 15:21. The THS continued to move, and by 15:27 had reached -7.4° from -l0.9° (where it had been at 15:21). Movement then appears to have stopped owing to the pitch-trim tripping.
Tripping of the pitch-trim is considered to occur when one of a certain number of conditions is met, such as when the AOA cannot be calculated correctly owing to low speed and unstable aircraft attitude. The alpha4rim function is designed to stabilize the longitudinal aircraft attitude by trimming the THS automatically in the nose-down direction (maximum 40 nose down), in conditions of high pitch and low speed.
The A300-600 is equipped with the following systems, for the purpose of THS motion awareness.
In this event of the accident involving the THS, systems (1) and (2) above are not always in pilots' field of view, and cannot alert them actively to the THS motion. Moreover this accident occurred in night and the cockpit was dark, so it is considered that these two systems did not provide pilots with effective information as to the status of THS-movement.
Furthermore, system (3) above was not active during the approach phase of this flight, because the APs were engaged in CMI).
During the development stage of the A300-600 aircraft, the motion warning had been designed to provide an aural warning "Whooler" when THS motion occurred in either automatic or manual flight, but the warning function was later eliminated from automatic flight by a design change.
On this matter, from a statement by the British aircraft accident investigation authorities the circumstance is as follows;
It is considered that, if the THS-in-motion warning had sounded continuously during an automatic flight, the crew would have recognized a significant change in flight configuration or suspected some anomaly in the AFS, and confirmed the operating conditions of the system.
A characteristic of the AP override function of A300-600 type aircraft is that a prolonged override of the AP acting on the pitch axis via the control wheel leads to an out-of-trim situation. Accordingly it is considered necessary for Airbus Industrie to have maintained the function of THS motion warning in the AP CMI) or, if eliminated, to establish another warning and recognition function which alerts pilots directly and positively to know the condition of the THS.
The fire fighting and rescue services at airports are specified in "Level of Protection to Be Provided" of Annex 14 "Aerodrome" to the Convention on International Civil Aviation and in the "Airport Services Manual" (hereinafter referred to as "ICAO Level") pertaining to it. Incidentally, the stipulations contained therein are considered desirable for safety, exactitude, and efficiency, and are categorized as "Recommended Practices", but not "Standards" at the present stage. In Japan, however, the fire fighting and rescue service is understood in principle to conform with the "ICAO Level", deploying and operating required vehicles etc. accordingly.
Nagoya Airport is managed by Nagoya Airport Office. The airport is used for international scheduled flights. Next to the airport is Komaki Base, Japan Air Self-Defense Force.
The Nagoya Airport Office is in charge of fire fighting and rescue services for civil aircraft.
At the time of the accident, the office had an emergency medical services transport vehicle on standby which was loaded with medical supplies. The office did not have chemical fire vehicles and other fire/rescue vehicles on standby at that time, but was in the process of equipping itself with these vehicles and other necessary equipment. Even though equipment acquisition was not complete, the office was capable of providing fire fighting and rescue services that conformed to "Level of Protection to Be Provided" for Category 9 airports recommended in Annex 14 to the Convention on International Civil Aviation, by utilizing fire fighting and rescue vehicles assigned to Komaki Air Base, Air Self-Defense Force, based on an agreement with them. The fire extinguishing foam solution discharge rates, however, did not completely satisfy the specified level.
Additionally, agreements were signed with neighboring fire fighting organizations, permitting utilization of their support. The fire fighting and rescue standards at Nagoya Airport were as follows:
(1) Airport Category
(2) Required Amounts and Discharge Rates of Fire Extinguishing Foam Solution
(1) |
Required Amount of Fire Extinguishing Agents |
According to the ICAO
Level, the minimum requirements for fire-extinguishing agents are
24,300 liters for water for foam production and 450kg for auxiliary
fire-extinguishing agent. The total amount of water for foam
production, including water available from the six fire fighting and
rescue vehicles (five chemical fire vehicles and a water supply
vehicle) assigned at Komaki Air Base, Air Self-Defense Force, was
33,600 liters and that of the auxiliary fire-extinguishing agent was
550kg, conforming with the amounts specified in the ICAO Level. | |
(2) | Discharge Rates |
According to the ICAO Level, the minimum foam solution discharge rate
is 9,000 liters/mm. The discharge rate of the five chemical fire
vehicles was 7,500 liters/mm (1,500 liters/mm x 5) which was
considered short of the rate recommended by the ICAO |
Level. | |
This was due to the low discharge rate of each chemical fire
vehicle. | |
The chemical fire vehicles assigned to Komaki Air Base had a
discharge distance of approximately 30m. |
(3) Response Time
(4) Numbers of Fire Fighting and Rescue Vehicles and Personnel
Fire fighting and rescue training for aircraft accidents are required to be conducted periodically, in order to maintain the competence of personnel who are to engage in fire fighting and rescue activities in the event of an emergency. Annex 14 "Aerodrome" to the Convention on International Civil Aviation has a "Standard" which requires all organizations concerned with fire fighting and rescue services to conduct pertinent training at intervals of less than two years. On May 24, 1993, organizations such as Air Self-Defense Force, neighboring fire fighting organizations, Airport Police and Medical Association of Aichi Prefecture, etc. participated in the fire fighting and rescue training for aircraft accidents under the auspices of Nagoya Airport Office.
Fire fighting and rescue activities were conducted as follows:
It is estimated that, after diving steeply without recovering from stall, and while rolling considerably, the aircraft impacted the ground almost in a level attitude. The aircraft was destroyed, and separated into forward fuselage, wings, aft fuselage, horizontal tail plane and vertical tail plane.
There is a possibility that the ethanol detected in the remains of the CAP and F/O was due to a Post-Mortem ethanol production. The possibility of alcoholic ingestion before death could not be determined. The possibility that liquor loaded onboard splashed the bodies of the CAP and F/O could not be confirmed.
It was recognized that China Airlines had an Operations Policy Manual
and an Air Crew Manning and Dispatch Manual prepared in accordance
with Taiwanese civil aviation laws, that the aircraft was operated
according to these manuals, and that both the CAP and the F/O held
valid qualifications for their respective duties.
The fact that the
CAP had allowed the F/O to operate the aircraft on this flight is
considered to satisfy the requirements of their crew qualifications,
aircraft weight, weather conditions and airport. As described in
Paragraph 3.2.3.(4), however, it is considered that the CAP's
situational awareness of the flight conditions was inadequate and that
control take-over was delayed.
they judged its implementation not urgent and decided to implement the modifications specified in this SB when FCCs needed repair. Therefore, this modification had not been incorporated in the aircraft by the time the accident occurred.
The contents of "Cautions" added to the FCOM, the descriptions in the
revision to FCOM associated with the AFS modification, and the
procedures for disengagement of GO AROUND mode are not easy to
understand. In addition, FCOM does not specify systematically the
primary purpose of the AP override function, the way to detect the
out-of-trim situation, and the procedure by which crews can recover
from it.
In addition to this, it is considered that of the technical
information distributed by Airbus Industrie to each operator after the
accident, the necessary and important items should be reflected in the
main body of FCOM.
The activation of alpha-floor function under the abnormal out-of-trim condition caused an sudden increase in the aircraft's pitch angle and contributed to its steep climb and subsequent stall.
Airbus Industrie, during the redesign phase, eliminated the aural whooler function which had been provided in the original design as THS motion warning when the AP is in CMI). It is considered that Airbus Industrie did not conduct sufficient studies as to whether to maintain the function to provide crews with THS motion awareness and attract their attention to continuous THS movement when the AP in CMI), or to incorporate an alternative device which
can alert crews to the THS out-of-trim situation.
It is recognized that the Nagoya Airport generally had a fire fighting and rescue system almost in conformity to the "Level of Protection to be Provided", recommended by the Convention to International Civil Aviation, except that the discharge rate of fire-extinguishing foam solution did not completely satisfy the specified level.
Peter B. Ladkin, 1999-02-08 | |
by Michael Blume |