Aerospatiale AS-355-F2 N355DU

Summary

On 17 October 2000 at about 03:55 local time, a Aerospatiale AS-355-F2 registered N355DU, operated by Corporate Jets, Inc., was involved in an accident near Burlington, North Carolina, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

17 October 2000 at 03:55

Classification

Accident

Location

Burlington, North Carolina, United States

Coordinates

36.0795, -79.4409

Aircraft

Aerospatiale AS-355-F2

Registration

N355DU

Category

Helicopter

Engines

2

Operator

Corporate Jets, Inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Ferry

Phase of flight

Not recorded

Route

Unknown → Durham

Aircraft damage

Destroyed

Weather

VMC

Light

Night/Bright

NTSB number

MIA01FA006

1 person died.

The mechanics failure to comply with manufacturers instructions for correction of a illuminated main rotor gearbox oil pressure warning light resulting in the helicopter being dispatched on a ferry flight with a failed main rotor gearbox oil pump, failure of the main rotor gearbox combining gearbox gears due to oil starvation, loss of main rotor RPM, and the helicopter colliding with trees and the ground during an uncontrolled descent.

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

Read the full NTSB narrative

About 5 minutes before landing at a hospital, the main rotor gearbox (MGB) oil pressure warning light illuminated. The pilot continued to the hospital, landed, and performed an immediate engine shutdown. A mechanic disconnected the wiring to the MGB oil pressure switch and the light went out. The mechanic stated he believed the oil pressure switch had failed and he asked the pilot to run the helicopter, hover the helicopter, and if everything was normal, to fly it back to the base hospital. The pilot did the run and hover, and then departed the hospital. The helicopter crashed about 1 minute later. Witnesses stated they heard the helicopter approach the crash site at a low altitude and making a slow thumping noise. Examination of the MGB showed the oil pump idler gear had seized in the oil pump due to undetermined reasons and the oil pump drive shaft had failed due to overstress. The teeth on the engine input gears, intermediate gears, and MGB drive gear in the MGB combining gearbox had failed due to high-temperature overstress, which was the result of oil starvation. The helicopter was not equipped with a MGB oil pressure indicator. The maintenance procedure for trouble shooting an illuminated MGB oil pressure warning light is to first check the electrical circuit, and if this does not correct the problem, to change the oil pressure switch. The mechanic stated he did not have the maintenance manuals with him while working on the helicopter. The MGB had been installed in the helicopter after overhaul, 3 days and 4 flight hours before the accident.

Quoted verbatim from the NTSB record.