Transportation Safety Board of Canada (TSB) confirms the main landing gear collapse in WestJet’s Boeing 737-800 at Sint Maarten was not because of hard landing event.
After a month-long investigation TSB found the fractured right gear aft trunnion pin and sent the two portions of the pin to the TSB Engineering Laboratory in Ottawa, Ontario for further investigation.
TSB investigation report
TSB has taken over this investigation from St. Maarten Civil Aviation Authority under the provisions of Annex 13 to the Convention on International Civil Aviation.
The board deployed a team to investigate and works closely with the WestJet, the Federal Aviation Administration, Boeing, and the U.S National Transportation Safety Board.
They confirmed that hard landing was not the cause of this accident after reviewing the flight data recorder data and during the aircraft examination they found out right gear aft trunnion pin of the aircraft was fractured.
The investigation team sent the fractured pin to the lab for further investigation and reviewing the previous occurrences of previous aft trunnion pin fractures on Boeing 737 aircraft.
What is aft trunnion pin
Aft trunnion pin is the extremely strong part in the aircraft which is made up of titanium and high-strength steel.
It acts as a major structural pivot joint which connects landing gear strut to the aircraft. It also carries the static (aircraft on the ground) and dynamic (taxing, landing etc…) loads.
During the gear extension and retraction, it the gear strut rotates in a hinge axis around the aft trunnion pin.
In simple way, aft trunnion pin is the support to the landing gear and helps in carrying the load of aircraft.
This aft trunnion pin was fractured and caused a landing gear collapse in WestJet WS2276 aircraft at St. Maarten airport.
What do you think is the reason behind aft trunnion pin fracture? Share your thoughts in the comments.
