What happened
On a morning flight from Boundary Bay, British Columbia, a Cessna U206G (registration C-FHMW) departed Chilliwack aerodrome for a short demonstration flight to the Cultus Lake area. The flight crew, consisting of two pilots and one passenger, intended to perform a water landing. During the departure from Chilliwally, the pilot moved the landing-gear selector to the UP position; however, the gear remained extended.
As the aircraft approached the water, the pilots discussed the necessity of having the undercarriage retracted. Based on cockpit indications, they believed the gear was up. Upon touching down on the water, the aircraft decelerated abruptly and overturned because the landing gear was extended. The pilot flying sustained fatal injuries, while the pilot-in-command and the passenger escaped with minor injuries.
The investigation
Investigators examined the wreckage and found the aircraft submerged and upside down. While the landing-gear selector was in the UP position, the gear itself was fully extended and locked in the DOWN position. The hydraulic-pump circuit breaker had tripped.
Technical logbooks revealed that the aircraft had been experiencing intermittent issues with the landing-gear system. Specifically, a faulty pressure switch had caused the hydraulic pump to overheat and trip the circuit breaker during previous flights. Although the pilot-in-command was aware of this defect, there was no formal documentation of the recent maintenance or the ongoing issue in the technical or journey logs.
Testing of the Wipline 3730 amphibious float system confirmed that the pressure switch was indeed intermittent. Furthermore, investigators found that the cockpit landing-gear indicator lights were set to the DIM position, making it harder to distinguish between the green (down) and blue (up) lights. Additionally, the aircraft was operating without the required flight manual supplements or specific checklists on board, relying instead on a simplified mnemonic.
Findings
- A faulty pressure switch in the landing-gear circuit caused the hydraulic pump to trip the circuit breaker upon arrival at Chilliwack.
- The landing-gear circuit breaker had tripped, preventing the pump from operating when the pilot selected the UP position for departure.
- The pilots failed to perform a complete pre-start check to ensure all circuit breakers were engaged.
- The crew did not utilize external visual indicators or notice that the cockpit lights remained green (indicating gear DOWN).
- The use of the DIM setting on the indicator lights reduced the visibility of the gear position status.
- The lack of documented maintenance history regarding the intermittent gear failure placed subsequent pilots at risk.