- Date
- July 21, 1991, 21:40 local (Jul 22, 1991, 04:40 UTC)
- Place
- Daggett, CA
- Injuries
- 3 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N58WHSikorsky SK-58
- Weather
- Visual (VMC) · Night/dark
- Status
- Completed · report April 8, 1993
- Report
- Approved by Office Director
- FAA report
- 19910722029099A
- Case key
- 27298
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 an engine connecting rod causing a reduction of engine power to the point where level flight could not be maintained. A factor in the accident was the dark night conditions which restricted the pilot's ability to select the best landing site.
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
While returning from an external load operation, the helicopter's engine started vibrating and then started back firing. The pilot reported hearing a loud 'bang' and then noted a decrease in engine power. He performed necessary emergency procedures and entered an autorotation. He said that he touched down with some forward speed. The helicopter hit a dirt berm. The rotor blades contacted the ground and the aircraft rolled over. An engine teardown was performed under the supervision of an FAA airworthiness inspector. A broken rod was found during the teardown. The teardown was terminated at that point and the reason for the broken rod was not determined.
Aircraft
- Registration
- N58WH
- Reported as
- Sikorsky SK-58
- Category
- Helicopter
- Serial number
- 11
- Engine
- Wright R-1820, 1,200 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Other work use · Part 133
- Operator
- Associated Helicopter Services
- Last inspection
- Unknown · January 2, 2000
- Departed
- DAG · Barstow, CA
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 42
- Certificates
- Flight instructor, Commercial
- Medical
- Class 1, Valid Medical--w/ waivers/lim
- Flight hours
- 6,000 total · 1,778 in this make and model · 49 in the last 90 days · 10 in the last 30 days
Weather
- Conditions
- Visual (VMC) · Night/dark
- Wind
- 270° at 9 knots
- Visibility
- 30 statute miles
- Lowest ceiling
- None
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.