Incident Overview
On a scheduled flight from Regina, Saskatchewan, to Calgary, Alberta, a McDonnell Douglas DC-9-32 aircraft operated by Air Canada experienced an engine failure during the takeoff run. The aircraft was carrying 63 passengers and a crew of five. At approximately 115 knots, the pilots heard muffled bangs and felt significant airframe vibration. They rejected the takeoff and brought the aircraft to a stop on the runway.
Evacuation and Response
After stopping, the captain initially ordered an evacuation via the forward galley emergency slide due to reports of smoke from the left side. The slide was deployed but high winds caused it to trail along the aircraft; an emergency responder stabilized it. Three passengers used the slide before the captain, advised that there was no smoke or fire, halted the slide evacuation and requested the airstairs. The remaining passengers exited using the main left front door and airstairs. All occupants evacuated without injury, though some experienced discomfort from cold weather conditions while waiting for transportation.
Aircraft Damage
The aircraft sustained substantial damage to the left engine and its cowlings, along with minor damage to the engine support pylon. Additionally, both right main landing gear tires were blown, and the left inboard tire showed severe skid damage. The anti-skid system had been disabled due to a subsequent electrical system failure linked to the engine rupture.
Engine Failure Cause
Investigation revealed that a crack had developed in the left engine's combustion chamber outer case (CCOC) through fatigue and intergranular fracture modes. The CCOC ruptured during the takeoff run, causing immediate loss of engine power. The crack had not been detected during maintenance inspections because of a misinterpretation of an airworthiness directive.
Cockpit Indications
The pilots did not initially observe any cockpit indications of engine failure, even though engine parameters likely changed rapidly. The loss of AC power from the left generator, combined with the AC cross-tie lockout, froze the left engine EPR reading at its last value of 2.04, providing erroneous information. The master warning lights also did not illuminate.
Tire Failures and Braking
The failure of the anti-skid system, due to the electrical fault, led to wheel lock-up when the captain applied maximum braking. The right-side tires skidded and eventually blew, likely because of unconscious compensation for asymmetric thrust. Despite this, the crew maintained directional control and stopped the aircraft near the runway centerline.
Flight Recorders
Both the flight data recorder (FDR) and cockpit voice recorder (CVR) ceased operating simultaneously during the takeoff roll. The FDR's recording mechanism had a pre-existing malfunction reducing its useful recording time, but neither recorder indicated any issue before the power loss.