IAD97LA028

NTSB accident investigation · Hughes 269C · Mayfield, KY · December 4, 1996

Accident · No injuriesLimited investigationFinal report
Date
December 4, 1996, 16:35 local (21:35 UTC)
Place
Mayfield, KY
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N1105PHughes 269C
Weather
Visual (VMC) · Day
Status
Completed · report March 31, 1998
Report
Approved by Office Director
FAA report
19961204037109A
Case key
28164

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

disengagement of the main transmission aft pinion nut, allowing the tail rotor splined drive sleeve to disengage from the pinion, which resulted in loss of directional control and an emergency (autorotative) landing.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Airframe/component/system failure/malfunctionCruise
Rotor drive system,tail rotor drive shaft - disengagedCause
Directional control - not possible
Forced landingEmergency descent/landing
Autorotation - performedPilot in command
In flight collision with objectEmergency landing
Object - fence

Analysis

The pilot stated that the purpose of the flight was to ferry the helicopter. The helicopter had been cruising at 1,200 feet MSL for over an hour, when the nose started to yaw to the right. Unable to control the yaw, the pilot entered an autorotation at about 70 mph to a field. During the forced landing, the helicopter collided with a fence. Examination of the helicopter revealed that the aft pinion nut of the main transmission had disengaged, which allowed the tail rotor splined drive sleeve to disengage from the pinion and tail rotor drive shaft. Investigation did not determined why the aft pinion backed off. The last annual inspection was completed on 6/7/96. The helicopter had accumulated 66 hours of flight time, since the annual inspection.

Factual narrative

On December 4, 1996, at 1635 eastern standard time, a Hughes 269C, N1105P, was substantially damaged when it collided with a fence during a forced landing near Mayfield, Kentucky. The certificated commercial pilot and passenger were not injured. Visual meteorological conditions prevailed and a flight plan was not filed. The ferry flight was conducted under 14 CFR Part 91, and originated in Henning, Tennessee, at 1530. The intended destination was Indianapolis, Indiana.

The pilot reported that he was ferrying the helicopter to the new owner. He said that the had been cruising at 1,200 feet MSL for about an hour, when the nose of the helicopter began to yaw to the right, followed by a change in aircraft noise. He attempted to correct the yaw by applying full left pedal, but was unsuccessful. He entered autorotation at about 70 mph, and attempted a forced landing to the middle of a field. During touchdown, the helicopter collided with a fence.

The helicopter was examined after the accident by an FAA Inspector. The examination revealed that the aft pinion nut of the main transmission disengaged during flight, which disengaged the tail rotor splined drive sleeve from the pinion, and the tail rotor drive shaft. It was not determined why the aft pinion nut backed off causing the drive spline to disengage. The last annual inspection was completed on June 7, 1996, and the helicopter had accumulated 66 hours since the annual inspection.

Aircraft

Registration
N1105P
Reported as
Hughes 269C
Category
Helicopter
Serial number
211028
Airframe hours
8,640
Engine
Lycoming HIO-360-D1A, 190 horsepower, reciprocating
Damage
Substantial damage
Flight
Ferry · Part 91
Registered owner
Dr. Charles Hassel
Airworthiness certificate
Standard, Normal
Last inspection
Annual · June 7, 1996 · 66 hours before
Departed
Henning, TN
Destination
I21 · Indianapolis, IN

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
32
Certificates
Commercial, Flight instructor
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
966 total · 119 in this make and model · 877 as pilot in command · 168 in the last 90 days · 61 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Visibility
10 statute miles
Lowest ceiling
None
Temperature
39 °F, dew point 36 °F
Altimeter
30.00 inHg

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.