Aerospatiale SA365-N1 accident near West Mifflin, Pennsylvania, December 18, 2000
On December 18, 2000 at about 8:30 pm local time, a Aerospatiale SA365-N1 (helicopter), registered N89SM, was destroyed in an accident near West Mifflin, Pennsylvania (Allegheny County airport). It was a flight test under general aviation rules (Part 91). 2 people were seriously injured; 1 other was unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Insufficient lubrication within the tail rotor gearbox, which resulted in the seizure of the duplex ball bearing and a fixed pitch setting of the tail rotor. Also causal, was the pilot's loss of control, which was the result of a relative low speed/high power combination during a go-around attempt. A factor was the manufacturer's lack of procedures for fixed tail rotor pitch settings.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 18, 2000 · about 8:30 pm local time
- Place
- West Mifflin, Pennsylvania · Allegheny County · map
- Type
- Accident
- Injuries
- 2 people were seriously injured; 1 other was unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale SA365-N1
- Registration
- N89SM · registry record · serial 6282
- Damage
- Destroyed
- Flight
- Flight test · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot stated he that performed a pre-flight inspection, checked the fluids, and ensured that the cowlings were closed and secured prior to conducting the helicopter's post-maintenance track and balance flight. In flight, after conducting several maneuvers, and while the helicopter was flying straight and level at 120 knots, the pilot noticed he had no anti-torque pedal control. He declared an emergency, and attempted numerous approaches to two different runways. Every time the helicopter slowed to 80-100 knots, the nose would swing to the left. During the final approach, while nearing touchdown on the runway, the pilot added collective, and the helicopter climbed while spinning to the left. The pilot reduced power, and the helicopter descended to, and impacted the ground while still in a left spin. Post-accident examination revealed that the bellcrank fitting at the tail servo input was broken, and there was very little oil in the tail rotor gearbox. There was no evidence of oil leakage at the seals or the filler cap. A small amount of oil was recovered, which was black in appearance. The oil level sight gage was marked with a black line, 6 to 7 mm below the minimum fill level. The output drive shaft duplex bearing displayed no evidence of lubrication. The inner races of the duplex bearing were removed and one displayed signs of wear and heat damage. The outer races contained metal transfers similar to the bearing cage, and the duplex bearing was seized. The flight manual did not contain any emergency procedures for a stuck (fixed pitch) tail rotor. -
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 9,100 hours in all; 140 in this make and model; 60 in the last 90 days; 20 in the last 30 days; 7,800 as pilot in command
- Last flight review: February 22, 2000
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 5,547 hours
- Last inspection: approved inspection programme, December 13, 2000; 2 hours since
- Maximum gross weight: 9,040 lb
- Seats: 6
- Landing gear: retractable
- Engine 1: Turbomeca Arriel 1C1 (turboshaft); 0 hours total
- Engine 2: Turbomeca Arriel 1C1 (turboshaft); 0 hours total
- Operator: Corporate Jets INC
The flight
- Departed from: AGC Pittsburgh PA at 8:00 pm
- Destination: Pittsburgh PA
- Flight plan: none
- Runway 23, 2,547 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: at 4 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 2,500 ft
- Temperature: 21°F (-6°C), dew point 10°F (-12°C)
- Altimeter: 30.04 inHg
- Observation at 8:32 pm from AGC
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.