What happened
On the night of August 31, 2008, a Cessna 172P, registered as C-GHSQ, began a series of night flights across Ontario. After departing Brampton Airport, the aircraft visited Toronto/Buttonville Municipal Airport, Barrie–Orillia (Lake Simcoe Regional) Airport, and Wiarton Airport. During the final leg of the trip, traveling from Wiarton back toward Brampton, the aircraft struck the ground approximately 7 nm west of Shelsebure, Ontario, at roughly 0432 EDT on September 1, 2008. The impact destroyed the aircraft, though no fire occurred.
The accident resulted in one fatality and one injury. While the rear-seat passenger was able to contact emergency services via cell phone, the crash site was not located by authorities until a local resident found it several hours later. The pilot and the front-seat passenger were airlifted to a hospital, where the front-seat passenger died four days later. The rear-seat passenger was treated and released.
The investigation
The investigation focused on the pilot and passengers, as weather conditions were suitable and no mechanical or navigational failures were identified. Investigators determined that the pilot had likely been awake for 22 consecutive hours, placing him at a high risk of involuntary sleep during the monotonous task of maintaining level flight at night. Both passengers were also experiencing low circadian alertness, and the rear-seat passenger was asleep at the time of the incident.
Flight path analysis showed that the aircraft deviated from its heading and entered a descending spiral. The investigation concluded that the pilot fell asleep, causing the aircraft to revert to its trimmed condition and fly into the ground. Additionally, the investigation found that the aircraft's takeoff gross weight exceeded the limits specified in the aircraft flight manual because an incorrect weight and balance worksheet was used.
Furthermore, the investigation noted that the emergency locator transmitter (ELT) failed to activate or transmit. This was due to the impact forces being insufficient to trigger the single-axis inertia switch and the physical detachment of the ELT's power source from its mounting bracket during the crash.
Findings
- The pilot involuntarily fell asleep due to fatigue, leading to the loss of directional control and the subsequent crash.
- The two passengers were asleep and failed to notice the developing flight path deviation.
- The pilot did not file a flight plan or itinerary, which prevented an early alert that the aircraft was overdue.
- The aircraft was operated at a gross weight exceeding its certified limitations.
- The design of the ELT mounting strap and the nature of the single-axis inertia switch contributed to the failure of the ELT to signal rescuers.