What happened
On a daylight flight from Matheson Island, Manitoba, to Poplar River, a Piper PA-31-350 Chieftain, registration C-GRNK, experienced a significant loss of power in its right engine immediately following lift-off. The aircraft, operated by Wamair Service & Out offitting Inc., was carrying one pilot and seven passengers.
As the aircraft climbed, the pilot observed black smoke trailing from the right engine. After identifying the power loss, the pilot shut down the engine and feathered the propeller. The aircraft was unable to gain altitude and remained at approximately 200 feet above ground level. In an attempt to return to the Matheson Island aerodrome, the pilot initiated a turning maneuver, but the aircraft lost further altitude during the turn. Realizing a return to the runway was not possible, the pilot executed a forced landing in a marshy area characterized by shallow water and tall reeds.
While the aircraft sustained substantial damage, there was no post-crash fire. The occupants were evacuated from the aircraft before water entered the cabin. The landing resulted in one serious injury and three minor injuries, while the remaining passengers were unhurt.
The investigation
Investigators examined the aircraft's right engine and its turbocharger system. They discovered that the differential pressure controller was defective, featuring a loose and leaking rubber bellows diaphragm and a poppet valve that was not securely adjusted. This malfunction caused the turbocharger waste gate to open, dropping the turbocharger offline and causing the fuel-air mixture to become too rich for efficient combustion, which led to the power loss.
Further examination of the operator's procedures revealed that the crew was using an unapproved quick reference handbook (QRH) rather than the approved aircraft flight manual (AFM). The QRH recommended a lower manifold pressure setting for takeoff than the AFM, which effectively reduced the available engine power during the most critical phase of flight. Additionally, the investigation noted that the takeoff roll was lengthened by the use of a gravel runway and a rolling takeoff technique.
Findings
- The right-engine turbocharger differential pressure controller malfunctioned, significantly reducing engine power during takeoff.
- The operator's use of an unapproved power-setting procedure reduced available engine power.
- The combination of a gravel runway, a rolling takeoff, and the timing of the engine failure prevented the aircraft from reaching its best single-engine rate of climb speed.
- The aircraft lacked sufficient altitude and airspeed to complete a successful return to the aerodrome.
- The aircraft was not equipped with enough seat-belt extensions for all passengers, and it lacked necessary equipment for over-water operations.