Probable cause
The separation of the main rotor head during cruise flight as a result of cyclic fatigue of the main rotor head spindle. The fatigue crack was due to an inadequate manufacturing process.
NTSB analysis
During a personal flight the experimental helicopter experienced an in-flight separation of the main rotor head. Both main rotor blades were located in opposite directions from the main wreckage. The helicopter was substantially damaged by the impact forces and the postimpact fire. Postaccident examination of the main rotor head assembly and the main rotor spindle revealed that the main rotor spindle had failed due to cyclic fatigue. The origin area was located near distinct circumferential machining marks. The manufacturer subsequently issued a mandatory inspection bulletin requiring inspection of all main rotor spindles.
Text from the NTSB. Open the NTSB docket for WPR09LA253 for the full record.
Event
- Date
- May 22, 2009
- Type
- Accident
- Place
- Rock Springs, Arizona
- Highest injury
- Fatal
- Fatal injuries
- 2
- Weather
- Visual (VMC)
- Light
- Day
Amateur-built SAFARI
- N-number
- N147MD
- Category
- Helicopter
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Personal
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.