# NTSB BFO86FA018: Hughes 500D, N8352F, Mt. Crawford, VA, March 9, 1986

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: March 9, 1986, 15:15 local (20:15 UTC)
- Place: Mt. Crawford, VA
- Coordinates: 38.35036, -78.939605 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.3504&lon=-78.9396&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 3 uninjured
- Status: Completed
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 11203
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO86FA018
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11203/pdf
- Page: https://openairdocs.org/ntsb/BFO86FA018

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, cruise - normal
  - rotor drive system,combining gearbox - fatigue (cause)
  - acft/equip,inadequate standard/requirement, manufacturer (cause)
  - rotor drive system,combining gearbox - failure,total (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- Hard landing, landing - flare/touchdown
  - terrain condition - rising (contributing factor)
  - level off - misjudged, pilot in command (cause)
- Roll over, landing - flare/touchdown

## Analysis

AFTER REFUELING AT SHENANDOAH VALLEY AIRPORT LOCATED NEAR STAUNTON, VIRGINIA, THE HELICOPTER CLIMBED TO ABOUT 1800 FEET MSL ON A NORTH HEADING. APPROXIMATELY 15 MINUTES AFTER DEPARTURE A LOUD RUMBLE WAS HEARD COMING FROM THE REAR OF THE AIRCRAFT AND THE PILOT IMMEDIATELY LOWERED THE COLLECTIVE AND ROLLED OFF THE THROTTLE. THE STUDENT PILOT, SITTING IN THE RIGHT FRONT SEAT, STATED THAT AFTER THE PILOT INITIATED THE FLARE, THE HELICOPTER 'HUNG IN THE AIR FOR A MONENT AT APPROX. 30' AGL THEN DROPPED TO THE GROUND AND ROLLED OVER.' DISASSEMBLY OF THE TAIL ROTOR DRIVE GEAR ASSEMBLY REVEALED THAT THE OUTPUT DRIVE PINION HAD FAILED. LABORATORY EXAMINATION REVEALED THAT THE FRACTURE SURFACES REVEALED MARKINGS TYPICAL OF FATIGUE PROGRESSION. MCDONNELL DOUGLAS HELICOPTER COMPANY HAD ISSUED AN ENGINEERING ORDER #139419 WHICH CONCERNED REWORKING THE DRIVE PINION, HOWEVER, A SERVICE BULLETIN WAS NOT ISSUED REGARDING THE NEED TO REWORK THE PINION AT OVERHAUL.

## Aircraft

- Registration: N8352F (not matched to a registry record)
- Reported make and model: HUGHES 500D
- Category: Helicopter
- Serial number: 1260066D
- Airframe hours: 1987
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Air Pegasus
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, March 4, 1986, 16 hours before
- Departed: SHD, SHENDANDOAH, VA
- Destination: MT. JACKSON, VA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 928 total, 110 in this make and model, 825 as pilot in command, 112 in the last 90 days, 35 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 15 knots
- Visibility: 25 statute miles
- Lowest ceiling: none
- Temperature: 70 °F, dew point 57 °F
- Altimeter: 30.00 inHg
- Observed at: SHD, 2 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 (OpenAirDocs).

- [Accident 19860309005799A](https://openairdocs.org/incident/19860309005799A), Mar 9, 1986: Hughes 369D, Mt Crawford, VA, Substantial damage. Loud rumble climbing after refueling. Returned flared too high. Dropped to ramp. Rolled. Output drive pinion failed

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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