- Date
- April 27, 1991, 08:30 local (13:30 UTC)
- Place
- Corpus Christi, TX
- Injuries
- 2 minor
- Damage
- Destroyed
- Phase of flight
- Maneuvering
- Aircraft
- N1195WBell 47G4
- Weather
- Instrument (IMC) · Day
- Status
- Completed · report March 31, 1993
- Report
- Approved by Office Director
- Case key
- 23322
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 initial restricted movement and eventual locking of the cyclic control as a result of the failure of the lateral servo. A factor was the installation of the failed component by an unqualified person.
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.
Analysis
A commercial pilot was maneuvering a helicopter to control a herd of cattle. The pilot noticed an intermittent binding in the left quadrant of the cyclic control. He notified his flight leader of his intentions to land and inspect the hydraulic servos in the flight control system, and initiated a precautionary landing close to their maintenance support vehicle. During the landing flare, the helicopter pitched sharply to the right rear as the lateral cyclic control became locked. The pilot applied full right pedal to try to cushion the landing and prevent the helicopter from rolling. The helicopter was destroyed upon impact with the mesquite trees. The failed lateral servo had been replaced by an unqualified person prior to this flight.
Aircraft
- Registration
- N1195W
- Reported as
- Bell 47G4
- Category
- Helicopter
- Serial number
- 3348
- Engine
- Lycoming VO-540-B1B3, 280 horsepower, reciprocating
- Damage
- Destroyed
- Flight
- Aerial observation · Part 91
- Operator
- W. J. Tiller, doing business as Tiller Helicopter Services
- Registered owner
- W. J. Tiller
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
- 42
- Certificate
- Commercial
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Helicopter, Airplane
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Flight hours
- 2,079 total · 130 in this make and model · 2,079 as pilot in command · 106 in the last 90 days · 68 in the last 30 days · 1 in the last 24 hours
Weather
- Conditions
- Instrument (IMC) · Day
- Wind
- 130° at 12 knots
- Visibility
- 2 statute miles
- Lowest ceiling
- 900 ft overcast
- Temperature
- -0 °F, dew point -0 °F