What happened
On March 3, 2016, a Jet Airways Boeing 737-900, registration VT-JGD, was operating a scheduled domestic flight from Delhi to Mumbai. The aircraft landed safely on runway 27 at 16:22 UTC. However, approximately 16 seconds after touchdown, while traveling at 58 knots, the right main landing gear collapsed. The crew reported a noise similar to a tire burst and observed the aircraft veering to the right.
In an attempt to maintain directional control, the first officer utilized the tiller to vacate the runway via taxiway N9. The aircraft eventually came to a halt on the taxiway, with its tail section still protruding onto runway 27. The collapse caused the aircraft to rest on its nose, the left main landing gear, and the right engine pod. Air traffic controllers observed sparks emanating from the right landing gear area as the engine cowl rubbed against the runway. While no fire broke out, hydraulic fluid spilled onto the taxiway, prompting fire services to apply foam to mitigate fire risks. All 120 passengers and 6 crew members disembarked safely via the L1 door using passenger stairs; there were no injuries.
The investigation
An inquiry by the AAIB India examined the mechanical failure and the maintenance history of the components involved. Investigators focused on the aft landing gear trunnion pin, which had undergone an overhaul by a facility in Norway. The investigation also scrutinized the airline's data management processes, specifically the use of the AMOS maintenance software. It was discovered that during a component exchange process, the airline's logistics staff had inadvertently extracted incomplete data, leading to a misunderstanding regarding which specific landing gear components were subject to recent overhaul services.
Findings
- The primary cause of the collapse was the failure of the right aft landing gear trunnion pin.
- Technical analysis revealed the pin failed due to base metal heat damage caused by abusive grinding of the chrome plating during its most recent overhaul.
- The fracture was linked to hydrogen embrittlement during the cadmium plating process and subsequent fatigue.
- Similar damage was identified in trunnion pins from previous incidents involving other aircraft in the fleet.
- Inaccurate data extraction from the AMOS system contributed to a lack of oversight regarding the component's maintenance history.
Safety action
- Jet Airways was advised to review its AMOS system to prevent future data extraction errors.
- The DGCA was advised to review regulations concerning the overhaul of aircraft components at foreign maintenance organizations that do not hold specific DGCA approval.