Investigation Summary
The flight was a routine 7-minute shuttle service between Moorea and Tahiti. Approximately 30 seconds after takeoff, as the aircraft reached 350 feet, the pilot retracted the flaps. This action typically causes a slight nose-down pitch, which the pilot counteracts by pulling back on the control column. The stress of this maneuver caused the already frayed elevator pitch-up cable to snap. The elevators dropped into a full nose-down position, sending the Twin Otter into a steep dive. The investigation by the BEA revealed that the stainless steel cables installed on F-OIQI were more prone to abrasion from cable guides than the original carbon steel versions. Furthermore, the aircraft was frequently parked in areas at Faa'a International Airport where it was exposed to jet blast from departing heavy aircraft, such as the Airbus A340. This jet blast caused the elevators to flutter violently against their locks, significantly accelerating the fatigue and fraying of the control cables.
Final Conclusions
The BEA concluded that the accident resulted from a loss of pitch control due to the rupture of the elevator pitch-up cable. Contributing factors included the use of stainless steel cables without adjusted maintenance intervals for high-cycle operations, the lack of pilot training for sudden pitch control failure, and the failure of airport and aviation authorities to mitigate the risks of jet blast on small aircraft parked near taxiing airliners.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Pilot was the sole crew member on board. His 110 hours at Air Moorea were his total hours on the DHC-6 type.
Systems & Failure Modes
Elevator Control System
A mechanical system using cables to move the elevators on the tail; the pitch-up cable snapped, leaving the elevators in a full nose-down deflection.
Cockpit Voice Recorder (CVR)
Although not legally required for this aircraft type, Air Moorea had voluntarily installed a CVR, which provided critical data for the investigation.
Ground Proximity Warning System (GPWS)
The CVR recorded six GPWS warnings as the aircraft dove toward the ocean.
Interesting Facts
- 01The flight was one of the shortest scheduled routes in the world, typically lasting only 7 minutes.
- 02The aircraft had completed 55,044 cycles in 30,833 flight hours at the time of the crash.
- 03The pilot, Michel Santeurenne, had 3,515 total flight hours, but his 110 hours with Air Moorea represented his total experience on the DHC-6 type.
- 04The wreckage was located on the seabed at a depth of 600 to 700 meters.
- 05Stainless steel cables were used for better corrosion resistance in the saline environment but were more susceptible to abrasion wear.
Safety Actions & Advisories
Cable Inspection Intervals
Recommendations were made to adjust maintenance schedules for stainless steel control cables to account for high-cycle operations rather than just calendar time.
Jet Blast Awareness
Authorities and operators were urged to implement stricter parking and taxiing procedures to protect small aircraft from the effects of jet blast from large airliners.
Known Controversies & Unanswered Questions
Manslaughter Convictions
Reference ↗Following the investigation, several Air Moorea officials and civil aviation authorities were charged with involuntary manslaughter. In 2019, a court in Papeete handed down prison sentences and fines to the airline's former manager and maintenance officials, ruling that negligence in maintenance and oversight directly led to the cable failure.