Probable cause
The failure of the vertical stabilizer control adapter due to reverse bending fatigue.
NTSB analysis
While in cruise flight, the helicopter experienced a hard right yaw and subsequent pitching moment up and down. The pilot was able to regain control of the helicopter and land without further incident. Examination revealed that the left vertical stabilizer control system adapter had failed. Metallurgical examination revealed that the failure mode was reverse bending fatigue. The vertical stabilizer control system adapter has been replaced with an improved design. Further, the Federal Aviation Administration has issued an Airworthiness Directive (AD) requiring all MD900 helicopter operators with the old VSCS tube adapters to comply with airspeed and autopilot restrictions. If an operator replaces the old VSCS tube adapter with the new design, the AD is not applicable.
Text from the NTSB. Open the NTSB docket for CEN09IA032 for the full record.
Event
- Date
- Oct 19, 2008
- Type
- Incident
- Place
- Amherst, Texas
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Md Helicopter Inc MD 900
- N-number
- N902NM
- Category
- Helicopter
- Damage
- Minor
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Positioning
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.