- Date
- August 12, 1994, 17:00 local (Aug 13, 1994, 01:00 UTC)
- Place
- Tok, AK
- Injuries
- 4 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N4059HHelio H-700
- Weather
- Visual (VMC) · Day
- Status
- Completed · report May 9, 1995
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- FAA report
- 19940812021389A
- Case key
- 2540
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 partial failure of the airplane's normal brake system.
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
After landing on the gravel bar on the robertson river, the left wheel's brake 'went soft.' The pilot allowed the airplane to continue the landing roll and prior to striking the ditch, he intentionally ground looped the airplane. During the ground loop the tail wheel struck the ditch and the fuselage buckled. Examination of the airplane showed that the left brake's torque plate had sheared and broken the brake line.
Factual narrative
On August 12, 1994, at 1700 Alaska daylight time, a wheel equipped Helio-Courier H-700 airplane, N4059H, registered to Charlie Warbelow and operated by 40 Mile Air, LTD, of Tok, Alaska, experienced a brake problem during landing on an airstrip located 40 miles southwest of Tok on the east fork of the Robertson River. The Air Taxi flight, operating under 14 CFR Part 135, departed Tok and the destination was the accident site. A company flight plan was in effect and visual meteorological conditions prevailed. The pilot and the three passengers were not injured. The airplane was substantially damaged.
According to the pilot, as he attempted to stop the airplane through the use of his brakes, the left brake went soft. He allowed the airplane to continue rolling and just prior to running into a ditch he intentionally ground looped the airplane. The tailwheel hit the ditch and the fuselage buckled behind the aft baggage compartment. The pilot stated the torque plate had sheared from the brake calipers and the brake line had broken.
The passengers were employees of the American Copper and Nickel Prospect. The operator did not submit their names on the NTSB Form 6120.1/2 at the time of the accident.
Aircraft
- Registration
- N4059H
- Reported as
- Helio H-700
- Category
- Airplane
- Serial number
- 09
- Airframe hours
- 1,160
- Engine
- Lycoming TIO-540, 350 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Part 135
- Operator
- 40 Mile Air, Ltd
- Registered owner
- Charles Warbelow
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · July 20, 1994 · 30 hours before
- Departed
- TKJ · AK
- Flight plan
- Company VFR
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
- Certificate
- Airline transport
- Airplane ratings
- Single-engine land, Multi-engine land, Single-engine sea
- Instrument ratings
- Airplane
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 12,000 total · 2,000 in this make and model · 11,800 as pilot in command · 300 in the last 90 days · 40 in the last 30 days · 3 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Visibility
- 30 statute miles
- Lowest ceiling
- 4,000 ft broken
- Temperature
- 61 °F
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.
Other investigations on N4059H · 1
Matched to the same aircraft by N-number and date.