Flybe DH8D at Amsterdam on Feb 23rd 2017, right main gear collapse on landing

Last Update: May 31, 2018 / 15:31:13 GMT/Zulu time

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Photo of Flybe G-JECP, De Havilland Dash 8 (400) — Flybe G-JECP, De Havilland Dash 8 (400) (Photo credit: Craig Sunter / Flickr / License: CC by)

Incident Facts

Date of incident
Feb 23, 2017

Classification
Accident

Airline
Flybe

Flight number
BE-1284

Departure
Edinburgh, United Kingdom

Destination
Amsterdam, Netherlands

Aircraft Registration
G-JECP

Aircraft Type
De Havilland Dash 8 (400)

ICAO Type Designator
DH8D

Airport
Amsterdam Airport Schiphol, Amsterdam

Airport ICAO Code
EHAM

A Flybe de Havilland Dash 8-400, registration G-JECP performing flight BE-1284 from Edinburgh,SC (UK) to Amsterdam (Netherlands) with 59 people on board, landed on Amsterdam's runway 22 at about 16:55L (15:55Z) but came to a stop on the runway with the right main gear collapsed. The crew declared Mayday, Mayday, Mayday reporting the gear had collapsed, they were evacuating onto the runway. Tower reported fire brigades were already on their way and instructed the next arrivals to go around. There were no injuries, the aircraft sustained substantial damage.

A passenger reported the right main gear collapsed upon touch down.

A storm front is currently moving across Europe battering Ireland, UK, Benelux and Germany.

Late Feb 23rd 2017 the Dutch Onderzoeksraad (Safety Board, DSB) announced they have opened an investigation into the occurrence.

On Feb 24th 2017 the DSB announced the UK AAIB is joining the investigation representing the state of the operator, the AAIB have dispatched investigators to Amsterdam.

On May 31st 2018 the DSB released their final report concluding the probable causes of the accident were:

- Maintenance was performed on the night before the day of the mishap flight, during maintenance the MLG brace was replaced. The maintenance crew stated they did not find anything unusual during the installation of the brace.

- After the accident, the newly installed stabilizer brace showed no deformation, nor did the attachment lugs on the yoke or the forward nacelle.

- The PSEU showed several fault codes which were consistent with the condition of the aircraft during the approach and after the incident.

- One of the MLG down lock sensors was found unreliable. The faulty sensor prevented the PSEU logic from closing the aft RH MLG doors and activating the unlock actuator.

- The unlock actuator not being activated prevented the brace being aided to maintain its over centred position by hydraulic pressure.

- The RH MLG yoke was found deformed. Analyses, and the fact no deformation was present on the stabilizer brace assembly, indicate that the deformation on the yoke was present prior to touchdown at Schiphol, and that this deformation was caused when NO stabilizer brace assembly was installed.

- The deformation of the yoke placed the RH MLG in a condition outside the certification state, thereby exposing the RH MLG stabilizer brace assembly to the potential of unlocking.

- The bent yoke caused friction in the MLG yoke and brace combination, which prevented at least one of the two stabilizer brace apex joints from achieving an over centre condition when the MLG was extended prior to landing. Although not designed for this, not hydraulically activating the unlock actuator after the gear was in the down position, prevented the brace assembly from being retained into over centre position.

- Despite the fact the gear was not fully locked, and outside certification condition, three green lights indicated to the crew that the gear was down and locked. Although not noticed by the flying crew, the amber caution light indicating the aft RH MLG were open, most likely was lit during landing.

- The combination of friction caused by the bent yoke, and faulty sensors preventing the unlock actuator to be activated, caused a situation whereby the stabilizer brace of the RH MLG did not get into over centre position causing an instable situation, despite the three LG green lights illuminated.

- During an asymmetric (rolled) touchdown in Amsterdam torsion loads were applied to the MLG, and the MLG strut collapsed almost immediately after touchdown of the RH MLG, causing the accident to happen.

The DSB analysed:

Examination of the AML does not show any landing gear problems in the period from February 10th until February 22nd. On this last date, technical orders Q400/32/12965 and Q400/29/12343 were performed. Scheduled replacement of the RH MLG stabilizer brace assembly (Airworthiness Directive) and replacement of the LH and RH MLG upper Hydraulic flex hoses were performed the day prior to the mishap flight. The stabilizer brace assembly comes with pre-installed proximity sensors, thus by replacing the brace, the sensors are also replaced.

According to the maintenance crew nothing unusual was noticed during maintenance activities. Maintenance crew stated that positioning of the brace assembly went smoothly and did not require force to position all four of the pins holding the brace in place. It is unclear if the gear, when in a bend position to be able to take the pins out and reinstall them, was moved slightly to make removal and installation of the pins easier. When replacing the brace assembly, there was no need to check if the MLG yoke showed indications of bending, twisting or misalignment.

After the replacement of the brace assembly and sensors, a ground functional test was performed with the aircraft on jacks, whereby the gear was lowered and raised several times using the aircraft’s on-board power unit. The gear operated normally, the brace assembly came in the over-centre position, proximity sensor indications were normal, and the solenoid sequence valves were activated, closing the MLG aft doors and extending the MLG unlock actuator.

...

Based on the analysis conducted by the landing gear manufacturer, and the fact there was no deformation or damage found on the stabilizer or yoke attachment lugs, the deformation on the yoke most likely was present prior to touchdown at Schiphol. This deformation was caused when NO stabilizer brace assembly was installed.

This situation only exist when the aircraft is under construction or maintenance. It is not determined when the deformation of the yoke occurred, this could have happened at any time between production and the time of last maintenance on the aircraft.

Metars:
EHAM 231555Z 24031G46KT 210V270 9999 -RA FEW020 SCT028 BKN037 08/04 Q0985 TEMPO 7000 BKN020
EHAM 231525Z 24037G51KT 9999 -RA FEW020 SCT032 08/04 Q0985 TEMPO 7000 BKN020
EHAM 231455Z 23034G48KT 180V260 9999 FEW022 09/03 Q0985 TEMPO 7000 -RA BKN020
EHAM 231425Z 23031G42KT 200V270 9999 FEW022 09/04 Q0986 TEMPO 7000 -RA BKN020
EHAM 231355Z 23031G45KT 9999 FEW025 10/05 Q0986 NOSIG
EHAM 231325Z 24032G46KT 200V260 9999 FEW025 10/06 Q0987 NOSIG
EHAM 231255Z 23033G47KT 9999 SCT016 10/07 Q0987 NOSIG