Report / August 24, 2005 / Project number: CT114120 - A Category
Location: Thunder Bay, Ontario
Status: Investigation Complete
The Flight Safety Investigation Report (FSIR) is available from DFS.
The accident aircraft was flying the "opposing solo" position for 431 Air Demonstration Squadron and was preparing to participate in an eight-plane display that was to take place at the Thunder Bay, Ontario waterfront. The "solos" were broken off from the main formation after take off to conduct a showline recce at the Thunder Bay harbour breakwater and to then conduct the pre-show "shakeout", a series of preliminary aerobatic manoeuvres designed to ensure the aircraft is set up properly before the formal start of the demonstration. One part of this sequence is for the aircraft to roll inverted and push negative 2 "G".
Immediately after achieving the inverted flight position, number 8 heard a loud bang and felt immediate loss of thrust. The pilot depressed the airstart button and the aircraft was returned to upright flight with the engine RPM quickly decaying to between 2 and 3 percent. The pilot attempted an engine relight with no success. He then ejected and the aircraft impacted the ground 10 seconds later near some derelict vehicles, in a field about nine kilometres north of the Thunder Bay airport. The aircraft was destroyed.
The pilot landed about ½ kilometre northeast of the aircraft and was recovered, with minor injuries sustained in the ejection sequence, about 20 minutes later.
The cause of the accident was the result of a catastrophic engine failure due to the separation of one of the first stage compressor blades, that moved rearward through the engine, causing massive and sudden damage to the rest of the compressor. The compressor first stage blade failed at the lugs due to progressive fatigue cracking. The accident engine had undergone maintenance for blade tip rubbing within the previous year, which was neither completed in accordance with CFTO procedures nor properly documented.
Several Aviation Life Support Equipment (ALSE) issues were also identified in the investigation. The pilots Seat Pack Survival Kit separated from the parachute during descent due to incorrect stitching on the maritime lanyard. The pilot's oxygen mask was not assembled with the correct matching visor, and the pilot's helmet had 12 layers of paint vice the normal 5 layers.
Preventive measures have already been implemented by the CT114 community with respect to the blade tip rubbing inspection process. Most of the ALSE related preventative measures have also been implemented by the Technical Airworthiness Authority.