Hughes 369D N911FT

Summary

On 20 April 2007 at about 00:05 local time, a Hughes 369D registered N911FT was involved in an accident near Kahuku, Hawaii, United States. 4 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

20 April 2007 at 00:05

Classification

Accident

Location

Kahuku, Hawaii, United States

Nearest airport

Turtle Bay Hilton Heliport (HI58)

Coordinates

21.7047, -158.0056

Aircraft

Hughes 369D

Registration

N911FT

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Honolulu → Kahuku

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA07LA108

2 people had minor injuries.

Fatigue cracking of the oil line from the engine gearbox to the oil pressure gauge, which resulted in loss of engine lubricating oil, leading to seizure of the power turbine.

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

Read the full NTSB narrative

During an aerial surveillance flight, the helicopter's engine chip light illuminated, and the pilot headed towards a nearby heliport to make a precautionary landing. The pilot established a steep fast approach in case of engine failure while on approach. At approximately 100 feet above the ground and an airspeed of 65 knots, he applied power and began to slow the helicopter. At this point, the engine lost power, and the pilot entered an autorotation. The helicopter landed hard breaking both forward landing gear struts and spreading the rear struts. The main rotor blades impacted the tail boom, and the tail boom separated from the fuselage. Examination of the helicopter revealed heavy deposits of oil on the inner surfaces of the engine compartment as well as on the exterior surfaces of the engine. There was no oil in the airframe engine oil reservoir. The oil line leading from the engine gearbox to the oil pressure gauge was found cracked beneath the "B" nut securing it to the fitting on the engine gearbox. The N2 (power turbine) drive could not be rotated. Partial disassembly of the engine revealed damage to the number six, seven, and eight bearings consistent with a lack of adequate lubrication. Laboratory examination of the cracked oil line found fatigue cracking had propagated through an estimated 90 percent of the cross-sectional area of the tube. The cracking allowed lubricating oil to leak from the line resulting in oil starvation to the bearings leading to seizure of the power turbine.

Quoted verbatim from the NTSB record.