History of the Flight
The medical evacuation flight departed Wollaston Lake, Saskatchewan, at 2325 central standard time en route to La Ronge. After take-off, the aircraft turned about 70 degrees to the left, descended, and struck the frozen surface of Wollaston Lake. The aircraft was destroyed. Witnesses observed an unusually shallow climb angle and a left turn before the aircraft disappeared from view.
Injuries and Damage
The pilot and the patient suffered serious injuries; the other two occupants suffered minor injuries. The aircraft was destroyed. The accident occurred at night, at coordinates 58°6.98'N, 103°10.79'W, elevation 1,300 feet asl, temperature approximately -25°C.
Pilot Information
The pilot, aged 27, held an Airline Transport Pilot Licence with 4,920 total flying hours, including 450 hours on type. He had 2 hours on duty prior to the occurrence after 22 hours off duty.
Aircraft Information
The aircraft was a Piper PA-31-325, serial number 317712050, manufactured in 1977. It was equipped with two Lycoming engines: left TIO-540 F2BD and right LTIO-540 F2BD, and two Hartzell propellers. Maximum take-off weight was 6,500 pounds. Maintenance records indicated proper certification and maintenance.
Wreckage and Impact
The left wing was completely severed from the fuselage, with overload failures at attachment points. The right wing was bent downward, rupturing fuel tanks. Both propellers detached; the left propeller had more severe damage, including broken start lock pins. The cockpit area was crushed predominantly on the right side. All seat controls were fully forward; fuel selectors were in main tank positions. No pre-impact structural failure was found.
Tests and Examination
Examination of the left propeller revealed broken start lock stop pins and damage to the high pitch stop sleeve. The damage indicated that the start locks were likely engaged and the propeller pitch was at the start lock position at impact. The right propeller showed no start lock damage. The propeller governors were functional. The cockpit instruments showed no pre-impact electrical arcing. The vacuum attitude indicator performed normally after being refrigerated.
Performance Issues
According to the Pilot's Operating Handbook, maximum climb rate under conditions was 1,370 fpm with both engines. With one engine windmilling, climb rate would be under 200 fpm, and nil if turning toward the failed engine. The aircraft was observed climbing at a shallow angle and attaining about 100 feet agl before turning left and disappearing.