What happened
On July 5, 1970, Air Canada flight 621, a DC-8-63 registered as CF-TIW, was operating a routine flight from Montreal International Airport to Toronto International Airport. The aircraft was carrying 100 passengers and nine crew members. During the approach to runway 32, the crew performed a before-landing checklist but omitted the specific instruction regarding arming the spoilers.
As the aircraft descended to approximately 60 feet above the runway, the First Officer manually deployed the ground spoilers. This action caused the aircraft to lose lift and sink rapidly toward the runway. In an attempt to recover, the Captain applied full power to all four engines and pulled back on the controls, but the aircraft struck the runway with significant force. The impact caused the number 4 engine and its pylon to separate from the wing, leading to a fuel leak and subsequent fire.
Following the initial touchdown, the aircraft briefly climbed to 3,100 feet. During this period, the crew communicated with air traffic control, believing they could circle for another approach. However, a series of three explosions occurred in rapid succession near the right wing. The second explosion caused the number 3 engine and pylon to detach, while the third resulted in the loss of a large section of the right wing. The aircraft entered a violent maneuver, lost altitude rapidly, and struck the ground at approximately 220 knots. All 109 fatalities occurred during the crash.
Findings
Investigations into the accident identified several contributing factors related to cockpit procedures and aircraft design:
- The Captain failed to follow established checklist procedures regarding the arming of ground spoilers.
- The First Officer manually moved the spoiler lever to the extend position while in flight.
- The aircraft design lacked a mechanical gate or safeguard to prevent the manual deployment of spoilers during flight.
- Inadequate warnings in the manufacturer's manuals and airline training regarding the risks of manual spoiler deployment.
- Structural failures in the engine pylon attachments prevented safe separation during the high-stress event, leading to fuel ignition.