What happened
During the final approach phase, approximately 3/4 mile southwest of the airport, a Casa 212 aircraft entered a nose-low attitude while emerging from cloud cover. A witness at the scene reported hearing sounds consistent with propellers entering reverse pitch immediately before the impact. The flight crew, consisting of five fatalities, was unable to recover the aircraft from its descent.
Findings
Investigation of the wreckage and flight recorders provided several technical insights into the accident. Cockpit Voice Recorder (CVR) data indicated an abrupt change in both frequency and amplitude roughly 10 seconds before the aircraft struck the ground. Physical examination of the engine components revealed that the left engine beta indicator lamp showed heavy oxide deposits and stretched coils, suggesting the lamp was illuminated at the moment of impact. While the right engine beta lamp was destroyed, the power levers and beta mode trigger locks were found to be functioning as intended, with intact return springs and no signs of excessive wear on the flight idle stops.
Testing of the power lever beta blocking device lockout solenoid confirmed it was electrically functional. However, the physical rigging of the beta lockout device could not be assessed due to the extent of the impact damage. Following the accident, the operator performed functional tests on the remaining eight Casa 212 aircraft in their fleet; during these checks, three aircraft were found to have inoperative electrical or backup beta blocking devices. It was noted that there were currently no established inspection or functional testing requirements for these specific blocking devices from either the manufacturer or the operator, identifying unregulated maintenance of beta blocking devices as a critical factor.