What happened
On a training flight departing the Region of Waterloo International Airport in Ontario, a Robinson R22 helicopter, registration C-GVAR, crashed into a drainage swamp on airport grounds. The flight, which included an instructor and a student, was intended to be a basic navigation exercise. After completing pre-flight procedures near the company hangar, the crew repositioned to a grassy area south of the approach path. During a brief delay caused by radio congestion, the crew began practicing hover maneuvers. At approximately 1131 Eastern Standard Time, roughly one minute after takeoff, the engine failed, leading to a crash that resulted in one fatality and one serious injury.
The investigation
Investigators examined the aircraft and the environmental conditions at the time of the accident. While the engine was not running at the moment of impact, no mechanical defects were found that would have prevented normal operation. The investigation focused on the weather, noting that the temperature and dew point spread at the airport were highly conducive to carburetor icing, a condition likely worsened by the moisture from the wet grass during hovering maneuvers.
At the time of the crash, the carburetor heat control was found in the 'cold' position. Investigators could not confirm if the heat had been applied during the critical takeoff phase, but noted that the 'cold' setting could indicate either a failure to apply heat or a manual de-selection following engine roughness. The investigation also assessed the flight path, noting that the presence of hangars and overhead wires made an emergency autorotation extremely difficult. The crew's attempt to reach a clear field 60 feet beyond the crash site likely involved raising the collective, which caused the rotor RPM to decay until flight could no longer be sustained.
Findings
- The primary cause of the engine failure was likely ice accumulation within the carburetor.
- Environmental conditions, including the temperature/dew point spread and wet ground, significantly increased the risk of icing.
- The aircraft's position over buildings and utility wires restricted the availability of suitable landing sites.
- The loss of rotor RPM, following an attempt to maneuver toward a clear field, led to the vertical descent into the swamp.