- Date
- March 31, 1991, 08:15 local (16:15 UTC)
- Place
- Waitsburg, WA
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N38926Bell BH-47G2A
- Weather
- Visual (VMC) · Day
- Status
- Completed · report May 5, 1993
- Report
- Approved by Office Director
- FAA report
- 19910331007939A
- Case key
- 41405
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The improper installation of the main rotor mast nut and lock washer by maintenance personnel which resulted in the separation of the main rotor system.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
While the pilot was lowering the collective pitch after landing touchdown, the main rotor separated fromt he mast. The examination revealed the improper installation of the mast nut and lock washer when the main rotor was installed.
Aircraft
- Registration
- N38926
- Reported as
- Bell BH-47G2A
- Category
- Helicopter
- Serial number
- NAH 1957-1
- Engine
- Lycoming VO-435A1F, 260 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Aerial application · Part 137
- Operator
- Waitsburg Helicopter Service
- Registered owner
- Waitsburg Helicopter Service
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 45
- Certificate
- Commercial
- Medical
- Class 2, Valid Medical--w/ waivers/lim
- Seat
- Left
- Flight hours
- 8,000 total · 8,000 in this make and model · 8,000 as pilot in command · 150 in the last 90 days · 40 in the last 30 days · 2 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 340° at 5 knots
- Visibility
- 50 statute miles
- Lowest ceiling
- None
- Temperature
- 46 °F, dew point 39 °F
- Altimeter
- 30.00 inHg
- Observed at
- PSC, 37 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.
Other investigations on N38926 · 5
Matched to the same aircraft by N-number and date.