Hughes 269B N9396F

Summary

On 11 December 2006 at about 21:45 local time, a Hughes 269B registered N9396F was involved in an accident near Houma, Louisiana, United States. 2 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 December 2006 at 21:45

Classification

Accident

Location

Houma, Louisiana, United States

Nearest airport

Houma-Terrebonne Airport (KHUM)

Coordinates

Not recorded

Aircraft

Hughes 269B

Registration

N9396F

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Houma → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

DFW07CA037

Nobody was injured.

A partial loss of engine power as a result of a cracked engine cylinder and broken spark plug which resulted in a hard landing. A factor was that it was not possible to attain proper rotor RPM.

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

Read the full NTSB narrative

The 2,873-hour flight instructor, who reported having accumulated 550-hours in the same make and model helicopter, reported that during a training flight, while practicing touchdown autorotations, the helicopter shuttered with a slight vibration through the airframe on climb out. The flight instructor added that the vibration stopped and he elected to continue the climb turning toward a downwind leg for the next autorotation. The helicopter shuttered again, this time much more violently, while on the downwind leg. The pilot stated on the NTSB Form 6120.1, Pilot/Operator Accident/Incident Report, that "I felt like the gearbox was locking up or something." The rated student pilot who was flying the helicopter at the time then declared "you've got the controls" to the instructor. The flight instructor immediately entered autorotation and the shutter stopped. In an attempt to regain powered flight the instructor then reapplied throttle which immediately created a violent vibration again and he decided to roll throttle completely off and continue with the emergency landing. The altitude at the onset was approximately 400 feet above ground level (agl). The flight instructor initiated a 180-degree turn autorotation to align the helicopter into the prevailing wind. The flight instructor also stated that the transfer of controls and attempt to regain powered flight, followed by the delay in entering the autorational turn, created a low airspeed and low rotor RPM situation that made the successful landing not possible. The flight instructor stated that he "waited until the last second and pulled the collective up to the stops and prayed." The helicopter landed hard and managed to remain in the upright position. The flight instructor and the rated student pilot were not injured. An FAA inspector, who traveled to the site, noted that the spark plug and helicoil was broken out on the number two cylinder. Further inspection of the number two cylinder revealed three separate cracks in the cylinder wall. At the time of the accident, the winds were reported from 070 degrees at 10 knots, gusting to 15 knots.

Quoted verbatim from the NTSB record.