Accident Overview
During climb after departure from Anchorage Airport, the pilot of a general aviation aircraft encountered technical problems with the flight instruments. The aircraft was operating in conditions of zero visibility due to clouds and fog. While in instrument meteorological conditions, the airplane descended until it struck the ground and crashed several miles from Anchorage. The aircraft was destroyed by impact forces and all seven occupants sustained fatal injuries.
Probable Cause and Contributing Factors
The investigation determined the probable cause of the accident to be a controlled collision with ground following the failure of a fluxgate compass. Contributing factors reported include:
- Failure of flight and navigation instruments: The fluxgate compass failed due to chafed flux detector wires.
- Material failure: The fluxgate compass itself was subject to material failure.
- Pilot error: The pilot failed to use or incorrectly used miscellaneous equipment.
- Air traffic control issues: ATC failed to properly identify the aircraft on radar. Additionally, ground control could not communicate directly with departure control.
- Weather conditions: Low ceiling, rain, fog, and zero visibility were present.
- Transponder issue: The aircraft was observed with an IFR arrival transponder code after departure.
Instrument Failure Details
The fluxgate compass malfunction originated from chafed flux detector wires, leading to inaccurate heading information. This failure compromised the pilot's ability to maintain spatial orientation in the low-visibility environment, resulting in an uncontrolled descent into terrain.
Meteorological Conditions
At the time of the accident, the weather was characterized by low ceilings, rain, fog, and zero visibility. These conditions likely prevented the pilot from visually acquiring the ground or obstacles, contributing to the loss of control.
ATC Communication Breakdown
Radar identification of the aircraft was not properly achieved by ATC personnel. Furthermore, communication between ground control and departure control was hampered because the two facilities could not communicate directly. The transponder was set to an IFR arrival code after departure, contrary to typical departure procedures.
Conclusion
While the official cause is the controlled collision with ground from fluxgate compass failure, multiple factors—including instrument malfunction, pilot actions, ATC errors, and adverse weather—all played roles in the accident sequence.