15th of August 2014, Blog #507
With a crew of two and one passenger, a British Aerospace 3102 Jetstream 31 was operating a flight from Belfast City Airport (Northern Ireland) to Doncaster / Sheffield-Robin Hood Airport (England). With the captain as Pilot Flying (PF) and co-pilot as Pilot Monitoring (PM) the aircraft took off at 17.45 lt.(local time).
The aircraft in its final position (© AAIB)
The flight to Doncaster was uneventful and at 18.20 the crew recorded the weather from the ATIS as;
Wind - 260º at 5 knots, varying 220º - 280º
Clouds - few at 3000 feet
Visibility - >10 kilometers
Temperature - 17 ºC
QNH - 1019 hPa
The crew requested runway vectors for a visual approach to runway 20, which was granted by ATC. The crew calculated a landing weight of 5059 kg on their loadsheet, requiring a Final Approach speed of 101 knots indicated.
At 18.36 lt the aircraft touched down at an indicated airspeed of 102 knots and an acceleration of 1.3 g. The power levers were moved to idle and then to reverse. A short while later, as the aircraft decelerated the power levers were put back to ground idle and the RPM levers to taxi.
8 seconds after touchdown, at speed of 65 knots, the left wing dropped and the aircraft started to yaw to the left. The PF was unable to maintain directional control, and the aircraft turned off the left side of the runway, coming to a stop on the grass at an angle of ~90º to the runway.
The aircraft as seen from the outside of the airport perimeter (Source; baaa-acro.com © Frankland) The left main landing gear had collapsed and the aircraft had settled on the baggage pannier and the remaining landing gears. While the PF secured the aircraft, th PM informed ATC. ATC replied that emergency services were on their way. After which an evacuation via the main cabin door on. Although did not open fully because of the aircraft's attitude, all occupants evacuated the aircraft safely. At 18.38 lt the emergency service arrive at the aircraft, and the evacuation was completed by then. The damage to the aircraft consisted of;
Broken left main landing gear, because of failure of the forward pintle housing
Left propellor blades badly damaged
Left aileron balance horn was broken off
Abrasion damage to the left wing, causing a fuel leak
Abrasion damage to the baggage pannier and anti-collision beacon
The aircraft being recovered from the runway (© SlightlyReliable70)
The Air Accident Investigation Branch (AAIB) investigated the accident and concluded its report with the following probable cause statement;
"The aircraft’s left main landing gear failed as a result of stress corrosion cracking in the forward pintle housing, at the top of the left landing gear cylinder. The landing gear material is known to be susceptible to stress corrosion cracking. The investigation determined that a design solution implemented by the aircraft manufacturer following a 2012 accident, which was intended to prevent stress corrosion cracking, had not met its original design intent".
The manufacturer undertook additional steps to prevent reoccurrence By clicking on the .pdf file below the reader will get access to the AAIB report on the accident.