West Atlantic B733 at Aberdeen on Mar 6th 2023, takeoff with incorrect flap setting

Last Update: February 8, 2024 / 11:55:41 GMT/Zulu time

Bookmark this article

Photo of West Atlantic G-JMCU, Boeing 737-300 — West Atlantic G-JMCU, Boeing 737-300 (Photo credit: Alec BHX/KKC / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Mar 6, 2023

Classification
Report

Airline
West Atlantic

Flight number
NPT-28E

Departure
Aberdeen, United Kingdom

Destination
East Midlands, United Kingdom

Aircraft Registration
G-JMCU

Aircraft Type
Boeing 737-300

ICAO Type Designator
B733

A West Atlantic Boeing 737-300 freighter, registration G-JMCU performing flight NPT-28E from Aberdeen,SC to East Midlands,EN (UK) with 2 crew, departed Aberdeen's runway 34 with flap setting 1 instead of 5 as planned. The crew noticed the wrong flap setting during flap retraction and continued to East Midlands for a safe landing without further incident.

On Feb 8th 2024 the British AAIB released their final bulletin into the occurrence rated a serious incident stating, that the actual takeoff parameters were sufficient for the flaps 1 takeoff, and concluding the probable causes of the serious incident were:

An incorrect flap selection was made and not detected before takeoff. A combination of poor weather conditions and time pressure may have influenced the pilot’s performance. It is necessary to check the actual flap position set, because the green configuration light indicates only that flap more than zero is set.

The AAIB analysed:

The poor weather conditions introduced several distractions on the fight deck before departure. The application of the SP 16 procedure put the pilots out of their normal sequence for setting takeoff flap. The task of taxiing in reduced visibility on a narrow taxiway would have taken more mental capacity than normal, and was likely exacerbated by the time pressure introduced by the worsening environmental conditions. It is possible the co-pilot reverted to the motor memory of selecting one flap detent, which was correct on the ATR 72 he had recently flown.

The commander visually confirmed the LE flap ext light was illuminated once lined up on the runway, but did not confirm the actual position of the flaps on the indicator.

Flap 1 is an allowable takeoff setting for a Boeing 737-300 and would not result in any further annunciations. There was therefore nothing to alert the pilots to the incorrect flap setting other than to check it themselves.

In this event, completing the takeoff with flap 1 did not have any effect on the safe conduct of the flight. In other circumstances where the takeoff performance was limited, such as an increased aircraft weight, reduced runway length or less favourable environmental conditions, there may have been a greater risk to the safety of the aircraft.

Metars:
COR EGPD 070150Z AUTO 34013KT 1000 SN BKN004/// BKN011/// OVC023/// //////TCU M01/M01 Q1000 TEMPO 4000 -SHSN BKN008=
COR EGPD 070120Z AUTO 30014KT 5000 -RA SCT027/// SCT040/// //////TCU M00/M01 Q1000 TEMPO 2000 SN BKN010=
EGPD 070050Z AUTO 30008KT 9999 FEW048 M01/M02 Q1000=
COR EGPD 070020Z AUTO 35005KT 9999 -SN SCT008/// //////TCU M01/M02 Q1000 RESN TEMPO 2000 SN BKN009=
COR EGPD 062350Z AUTO 32012KT 9999 SCT027/// //////TCU M00/M01 Q1000 TEMPO 2000 SHSN BKN010=
COR EGPD 062320Z AUTO 32011KT 9999 NCD M01/M02 Q1000 TEMPO 2000 SHSN BKN010=
COR EGPD 062250Z AUTO 35009KT 9999 -RA SCT006 BKN020 M01/M01 Q1000 RESN TEMPO 2000 SHSN BKN006=
COR EGPD 062220Z AUTO 33008KT 9999 FEW019 SCT026 BKN031 00/M01 Q1000 TEMPO 2000 SHSN BKN010=
COR EGPD 062150Z AUTO 31010KT 9999 FEW020 SCT026 BKN043 M00/M01 Q1000 TEMPO 2000 SHSN BKN010=
COR EGPD 062120Z AUTO 28010KT 9999 -RASN FEW020 SCT025 BKN031 00/M01 Q1000 TEMPO 2000 SHSN BKN010=
COR EGPD 062050Z AUTO 31007KT 9999 SCT020 BKN037 00/M02 Q1000 NOSIG=
COR EGPD 062020Z AUTO 33004KT 300V360 9999 FEW027/// SCT043/// //////TCU 00/M01 Q1001 NOSIG=
COR EGPD 061950Z 33010KT 9999 VCSH SCT018 BKN035 00/M01 Q1001 TEMPO 2000 SHSN BKN010=
COR EGPD 061920Z 31008KT 9999 FEW035 00/M02 Q1000 NOSIG=
COR EGPD 061850Z 31009KT 9999 FEW020 SCT042 00/M01 Q1000 TEMPO 2000 SHSN BKN010=