Aerospatiale SA365-N1 N89SM

Summary

On 18 December 2000 at about 20:30 local time, a Aerospatiale SA365-N1 registered N89SM, operated by Corporate Jets Inc, was involved in an accident near West Mifflin, Pennsylvania, United States. 3 people were on board and 2 were seriously injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

18 December 2000 at 20:30

Classification

Accident

Location

West Mifflin, Pennsylvania, United States

Nearest airport

Allegheny County (AGC)

Coordinates

40.3542, -79.9250

Aircraft

Aerospatiale SA365-N1

Registration

N89SM

Category

Helicopter

Engines

2

Operator

Corporate Jets Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Flight Test

Phase of flight

Not recorded

Route

Pittsburgh → Pittsburgh

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

NYC01LA059

2 people were seriously injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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. -

Quoted verbatim from the NTSB record.