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ASN Wikibase Occurrence # 138837
Last updated: 27 November 2021
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Date:06-SEP-2011
Time:22:49 JST
Type:Silhouette image of generic B737 model; specific model in this crash may look slightly different
Boeing 737-781 (WL)
Owner/operator:All Nippon Airways
Registration: JA16AN
MSN: 33889/2488
Fatalities:Fatalities: 0 / Occupants: 117
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:43km south of Hamamatsu -   Japan
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Okinawa-Naha Airport (OKA/ROAH)
Destination airport:Tokyo-Haneda Airport (HND/RJTT)
Investigating agency: JTSB
Narrative:
ANA Flight 140 was en route at FL410 when the first officer inadvertently used the rudder trim knob instead of the flightdeck door lock knob. The captain was returning to the flight deck when the first officer needed to unlock the door.
Consequently the airplane banked left to a maximum of 131.7 degrees and entered a steep descending turn. Control was regained at FL347.
During the event, the speed limit (Mach 0.82) was exceeded when the airplane flew at Mach 0.828. Also the acceleration limit (+2.5 G) was exceeded when the plane hit +2.68 G.

Probable Causes:
It is highly probable that this serious incident occurred in the following circumstances: During the flight, the first officer erroneously operated the rudder trim control while having an intention of operating the switch for the door lock control in order to let the captain reenter the cockpit. The aircraft attitude became unusual beyond a threshold for maintaining the aircraft attitude under the autopilot control. The first officer’s recognition of the unusual situation was delayed and his subsequent recovery operations were partially inappropriate or insufficient; therefore, the aircraft attitude became even more unusual, causing the aircraft to lose its lifting force and went into nosedive. This led to a situation which is equivalent to “a case where aircraft operation is impeded.”
It is probable that the followings contributed to the first officer’s erroneous operation of the rudder trim control while having an intention of operating the door lock control; he had not been fully corrected his memories of operation about the door lock control of the Boeing 737-500 on which he was previously on duty; the door lock control of the Boeing 737-500 series aircraft was similar to the rudder trim control of the Boeing 737-700 series aircraft in their placement, shape, size and operability. It is somewhat likely that his memories of operation about the switch for the door lock control of the Boeing 737-500 aircraft had not been fully corrected because he failed to be fully accustomed with the change in the location of the switch for the door lock control. It is somewhat likely that this resulted from lack of effectiveness in the current system for determining the differences training contents and its check method, under which the Air Nippon Co., Ltd. and other airlines considered and adopted specific training programs to train pilots about how to operate the flight deck switches when their locations changed and the Civil Aviation Bureau of the Ministry of Land, Infrastructure, Transport and Tourism reviewed and approved them. It is probable that the first officer’s failure to properly manage tasks contributed to his erroneous operation of the rudder trim control.
It is somewhat likely that the similarities between the switches for the door lock control and the rudder trim control in their operability contributed to the delay in his recognition of the erroneous operation. Moreover, he was excessively dependent on autopilot flight and he failed to be fully aware of monitoring the flight condition.
It is somewhat likely that the first officer’s recovery operations were partially inappropriate or insufficient because he was startled and confused on the occurrence of an unexpected unusual situation in which the stick shaker was activated during the upset recovery maneuver. It is somewhat likely that the followings contributed to his startle and confusion: he had not received upset recovery training accompanied with a stall warning and in unexpected situations, thereby he lacked the experience of performing duties in such situations before the serious incident, and he had not received upset recovery training at a high altitude.

Sources:

http://www.mlit.go.jp/jtsb/flash/JA16AN_110906-110928.pdf
Animation of the incident: http://www.mlit.go.jp/jtsb/video/JA16AN-movie1.wmv

Accident investigation:
cover
  
Investigating agency: JTSB
Status: Investigation completed
Duration: 3 years
Download report: Final report

Media:


Images:


Photo: JTSB

Revision history:

Date/timeContributorUpdates
28-Sep-2011 13:31 harro Added
28-Mar-2015 16:01 Anon. Updated [Narrative]
06-Apr-2015 13:35 Anon. Updated [Time]
26-Jan-2021 14:28 harro Updated [Narrative, Accident report]
26-Jan-2021 15:13 harro Updated [Departure airport, Destination airport, Embed code, Photo]

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