What happened
In the early evening, a Robinson R22 Mariner helicopter departed Lindsay, Ontario, bound for Toronto / Buttonville Municipal Airport. Simultaneously, a Cessna 170 took off from a private grass strip known as Sandford Field, intending to perform a single left-hand circuit.
While operating in visual meteorological conditions at approximately 700 feet above ground level, the two aircraft collided near Uxbridge, over a farmer's field. The collision occurred as the Cessna was climbing on a south-bound heading, intercepting the helicopter's flight path at a 50° angle. The impact caused catastrophic damage to the helicopter's main-rotor system and tail, leading the aircraft to pitch inverted and plunge to the ground. The pilot of the helicopter was fatally injured. The pilot of the Cessna managed to maintain control of the aircraft despite substantial damage to the propeller and engine cowl, successfully performing a forced landing in a nearby cornfield.
The investigation
The investigation examined the flight paths, aircraft maintenance records, and pilot qualifications. The helicopter's path was reconstructed using debris analysis and eyewitness accounts. Investigators found that the helicopter's design created a blind spot below the right cabin wall, preventing the pilot from seeing the approaching Cessna. Conversely, the Cessna's high-wing configuration obscured the helicopter from the pilot's view during the climb.
Regarding the aircraft, the Robinson R22 Mariner was found to be well-maintained and within weight limits. However, the Cessna 170 was operating with an expired certificate of airworthiness and had not undergone required inspections or maintenance since 1999. Additionally, while the helicopter was equipped with a transponder, the Cessna was not. The investigation also noted that the Cessna pilot was flying without a valid pilot licence or medical certificate.
Findings
- The collision was caused by the failure of both pilots to see and avoid the other aircraft due to inherent design-related visibility limitations and the specific intercept geometry.
- The lack of a traffic alert and collision-avoidance system (TCAS) on either aircraft deprived the pilots of a critical warning mechanism.
- The absence of mandatory radio communications or position reports in Class G airspace meant the pilots had no way to establish awareness of each other's proximity.
- The Cessna 170 was not properly licensed, and its airworthiness certificate had expired.