Unfallbericht:The Airbus took off from Taipei for a flight to Nagoya where it arrived over the Outer Marker at 20:12:26. The 1st officer started the runway 34 ILS-approach with auto throttles engaged. At an altitude of 1070 feet (at 145 knots and 5 degrees pitch) he inadvertently selected TOGA (Take Off Go Around) mode.
|Datum:||Dienstag 26 April 1994|
|Baujahr:|| 1990-10-30 (3 years 6 months)|
|Anzahl Zyklen der Zelle:||3910|
|Triebwerk:|| 2 Pratt & Whitney PW4158|
|Besatzung:||Todesopfer: 15 / Insassen: 15|
|Fluggäste:||Todesopfer: 249 / Insassen: 256|
|Gesamt:||Todesopfer: 264 / Insassen: 271 |
|Konsequenzen:|| Written off (damaged beyond repair)|
|Unfallort:||Nagoya-Komaki International Airport (NGO) ( Japan)
|Flugphase:|| Annäherung (APR)|
|Flug von:||Taipei-Chiang Kai Shek International Airport (TPE/RCTP), Taiwan|
|Flug nach:||Nagoya-Komaki International Airport (NGO/RJNN), Japan|
Unknowingly of the TOGA selection, the crewmembers tried to override the flight director's throttle and pitch control movements. In order to remain on the glide slope, the 1st officer disengaged the auto throttle and reduced thrust manually. At 1030 feet the crew hoped that the autopilots would get them on the glide slope, and engaged them. The autopilot immediately entered the go-around mode (because TOGA had been selected 12 seconds earlier) with an 18 degrees pitch up. To get back on the glide slope, the crew applied down elevator. This caused the flight director guidance system to select pitch-up stabilizer. Forty-two seconds after TOGA selection, the autopilots were disengaged again, but the aircraft kept climbing. Eight seconds afterwards, the alpha floor was activated due to an excessive angle-of-attack. Alpha floor triggered maximum thrust, which increased the nose-up attitude to 52.6 degrees. The captain disengaged alpha-floor by retarding engine thrust. The speed had dropped to 78 knots by then, causing the Airbus to enter a stall at 1800 feet.
The aircraft hit the ground tail-first 300 feet right of the runway and burst into flames. The weather was fine: wind 290 degrees/6 knots (varying between 230deg and 320deg) >10 km visibility; scattered clouds at 3000 feet.
Probable Cause:CAUSES: While the aircraft was making an ILS approach to runway 34 of Nagoya Airport, under manual control by the F/O, the F/O inadvertently activated the GO lever, which changed the FD (Flight Director) to GO AROUND mode and caused a thrust increase. This made the aircraft deviate above its normal glide path. The APs were subsequently engaged, with GO AROUND mode still engaged. Under these conditions the F/O continued pushing the control wheel in accordance with the CAP's instructions. As a result of this, the THS (Horizontal Stabilizer) moved to its full nose-up position and caused an abnormal out-of-trim situation. The crew continued approach, unaware of the abnormal situation. The AOA increased the Alpha Floor function was activated and the pitch angle increased.
It is considered that, at this time, the CAP (who had now taken the controls), judged that landing would be difficult and opted for go-around. The aircraft began to climb steeply with a high pitch angle attitude. The CAP and the F/O did not carry out an effective recovery operation, and the aircraft stalled and crashed.
The AAIC determined that the following factors, as a chain or a combination thereof, caused the accident:
* The F/O inadvertently triggered the Go lever. It is considered that the design of the GO lever contributed to it: normal operation of the thrust lever allows the possibility of an inadvertent triggering of the GO lever.
* The crew engaged the APs while GO AROUND mode was still engaged, and continued approach.
* The F/O continued pushing the control wheel in accordance with the CAP's instructions, despite its strong resistive force, in order to continue the approach.
* The movement of the THS conflicted with that of the elevators, causing an abnormal out-of-trim situation.
* There was no warning and recognition function to alert the crew directly and actively to the onset of the abnormal out-of-trim condition.
* The CAP and F/O did not sufficiently understand the FD mode change and the AP override function.
It is considered that unclear descriptions of the AFS (Automatic Flight System) in the FCOM (Flight Crew Operating Manual) prepared by the aircraft manufacturer contributed to this.
* The CAP's judgment of the flight situation while continuing approach was inadequate, control take-over was delayed, and appropriate actions were not taken.
* The Alpha-Floor function was activated; this was incompatible with the abnormal out-of-trim situation, and generated a large pitch-up moment. This narrowed the range of selection for recovery operations and reduced the time allowance for such operations.
* The CAP's and F/O's awareness of the flight conditions, after the PlC took over the controls and during their recovery operation, was inadequate respectively.
* Crew coordination between the CAP and the F/O was inadequate.
* The modification prescribed in Service Bulletin SB A300-22-602 1 had not been incorporated into the aircraft.
* The aircraft manufacturer did not categorise the SB A300-22-6021 as "Mandatory", which would have given it the highest priority. The airworthiness authority of the nation of design and manufacture did not issue promptly an airworthiness directive pertaining to implementation of the above SB.
» FAA Bulletin FSAT 95-13
» NTSB Safety Recommendations A-94-164/166
Flight profile of China Airlines flight 140
|30 OCT 1990
|02 FEB 1991
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not
display the exact flight path.
Distance from Taipei-Chiang Kai Shek International Airport to Nagoya-Komaki International Airport as the crow flies is 1870 km (1169 miles).
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.