Introduction
On a training flight at Hare Field, approximately 15 nautical miles northwest of Toronto/Buttonville Municipal Airport, Ontario, a Schweizer 269C (300C) helicopter, registration C-GGUV, was flown by an instructor and a student pilot. The flight was intended to practice autorotations with power-on recoveries in preparation for an upcoming flight test.
Aircraft and Crew
The helicopter, serial number S1806, was owned and operated by Silverline Helicopters Inc. It had accumulated approximately 200 total hours since new and was maintained in accordance with regulations. No pre-existing mechanical failure was identified. The instructor held a commercial pilot – helicopter licence for just over two years, with about 800 hours of helicopter experience and a Class IV instructor rating. The student held a student pilot permit and had about 80 hours of helicopter flight time, all at Silverline.
Flight Sequence
After taking off at approximately 1245 eastern daylight time, the student performed three straight-in autorotations from just above circuit altitude (1500 feet msl). The crew then commenced a 360° autorotation from a height of about 800 feet over the airfield. During the turn, the airspeed became abnormally low, the rate of turn was slow, and the rate of descent was abnormally high. The instructor took control at about 200 feet agl, at which point the airspeed was approximately 25 knots indicated and rotor speed was about 400 rpm. He lowered the nose to regain airspeed, then raised the nose near the ground, but did not add power or collective. The helicopter landed hard in a slightly nose-up attitude on soft turf, causing the skid heels to spread. The helicopter rolled forward and left, coming to rest inverted. It suffered substantial damage; both pilots received minor injuries. No post-crash fire occurred.
Aftermath
Personnel on the airfield assisted in the rescue. Both pilots were taken to hospital and released after treatment. The student, not wearing a helmet, sustained minor facial cuts. The instructor's helmet had superficial scratches.
Contributing Factors
The crew had not previously practiced 360° autorotations together. The student had learned the maneuver from another instructor using a minimum entry altitude of 1000 feet agl, but this flight's entry altitude was lower (circuit altitude of 650–750 feet agl). The briefing before the flight was abbreviated, covering only what would be done, not how. The reference material for the training lacked specific guidance on safe entry altitudes for 360° autorotations, and the aircraft flight manual warned against combinations inside the height-velocity curve. The student did not recognize the developing unsafe condition, and the instructor allowed the situation to progress before intervening.
Probable Cause
The source provided no definitive probable cause.