FTW04TA012

NTSB accident investigation · Hughes OH-6A · Eagle Pass, TX · October 7, 2003

Accident · Minor injuriesFinal report
Date
October 7, 2003, 11:58 local (16:58 UTC)
Place
Eagle Pass, TX
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N8524ZHughes OH-6A
Weather
Visual (VMC) · Day
Status
Completed · report March 30, 2004
Report
Approved by Office Director
Case key
58192

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

On this page

Probable cause

The failure of the aft segment of the tail rotor drive shaft for undertermined reasons. A contibuting factor was the lack of suitable terrain for the foced 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.

Rotor failure/malfunctionHover
Reason for occurrence undeterminedCause
Rotor drive system,tail rotor drive shaft - failureCause
Loss of control - in flightHover
Forced landingEmergency descent/landing
In flight collision with terrain/waterEmergency descent/landing
Terrain condition - none suitableFactor

Analysis

The 2,363-hour pilot reported that he was maneuvering the helicopter at an altitude of 30 to 60 feet AGL, with 5 to 10 knots forward airspeed when the nose of the helicopter started to move to the right. The pilot corrected for this with the left pedal. The nose of the helicopter stopped momentarily then started moving back to the right and could not be stopped with full left pedal. The helicopter was spinning uncontrollably to the right and the engine and rotor RPM increased. The pilot tried to hold the helicopter level with the cyclic, lowered the collective, held full left pedal and started to retard the throttle when contact with the ground occurred. The helicopter came to rest on its left side. The pilot reported that the tail rotor was not turning when the helicopter hit the ground. Examination of the helicopter by the operator revealed that the aft segment of the tail rotor drive shaft, approximately 24 inches forward of the tail rotor gear box attach point, was separated. The reason for the separation was not determined.

Factual narrative

On October 7, 2003, at approximately 1158 central daylight time, a Hughes OH-6A helicopter, N8524Z, registered to and operated by the U.S. Border Patrol, El Paso, Texas, was substantially damaged during a forced landing following a loss of tail rotor effect near Eagle Pass, Texas. The commercial helicopter pilot, sole occupant of the aircraft, sustained minor injuries. Visual meteorological conditions prevailed and a flight plan was not filed for the public use flight. The local flight originated at 1021 from the Del Rio International Airport, near Del Rio, Texas, and was destined for the Maverick County Memorial International Airport, near Eagle Pass, Texas.

According to the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the 2,363-hour pilot reported that he was maneuvering at an altitude of 30 to 60 feet AGL, with 5 to 10 knots forward airspeed when the nose of the helicopter started to move to the right. The pilot corrected for this by applying left pedal. The nose of the helicopter stopped momentarily then started moving back to the right and could not be stopped with full left pedal. The helicopter was spinning uncontrollably to the right and the engine and rotor RPM increased. The pilot tried to hold the helicopter level with the cyclic, lowered the collective, held full left pedal and started to retard the throttle when contact with the ground occurred. The helicopter came to rest on its left side. The pilot reported that the tail rotor was not turning when the helicopter hit the ground.

Examination of the helicopter by the operator revealed that the aft segment of the tail rotor drive shaft, approximately 24 inches forward of the tail rotor gear box attach point, was separated. The reason for the separation was not determined.

Aircraft

Registration
N8524Z
Reported as
Hughes OH-6A
Category
Helicopter
Serial number
65-12933
Airframe hours
14,156.8
Engine
Allison C-20 B, 420 horsepower, turbo shaft
Damage
Substantial damage
Flight
Public aircraft · Public use
Registered owner
U.S. Border Patrol Air Operations
Airworthiness certificate
Standard, Normal
Last inspection
Annual · June 30, 2003 · 35 hours before
Departed
DRT · Del Rio, TX
Destination
5T9 · Eagle Pass, TX

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
41
Injuries
Minor
Certificate
Commercial
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
Class 2, Valid Medical--no waivers/lim.
Last flight review
August 14, 2002
Seat
Right
Flight hours
2,363 total · 605 in this make and model · 2,165 as pilot in command · 182 in the last 90 days · 38 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
150° at 7 knots
Visibility
15 statute miles
Lowest ceiling
30,000 ft overcast
Temperature
86 °F, dew point 72 °F
Altimeter
29.94 inHg