- Date
- December 16, 2018, 12:00 local (19:00 UTC)
- Place
- Riggins, ID
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Takeoff
- Aircraft
- N4385BCessna 170
- Defining event
- Takeoff: Loss of control in flight
- Weather
- Visual (VMC) · Day
- Status
- Completed · report September 26, 2019
- Report
- Approved by Office Director
- NTSB office
- General Aviation Accidents
- Parties
- FAA
- FAA report
- 20181216022219A
- Case key
- 98778
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 pilot's improper preflight performance planning and his subsequent failure to attain sufficient speed for the airplane to climb with a tailwind.
Findings · 4
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The pilot of the ski-equipped airplane reported that he aborted his first attempt to take off, and during his second takeoff attempt with a tailwind, shortly after rotation, the airplane settled back onto the snow-packed runway. He added that the airplane lifted off again, but when it was about 5 ft above the ground and near the end of the runway, a wind gust pushed the airplane down onto the runway. Subsequently, the airplane overran the runway, and the right wing impacted a tree. The pilot did not know the wind direction and speed because the airport did not have a windsock or weather reporting station. The airplane sustained substantial damage to the wings. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot chose to depart to the north due to rising terrain and tall trees on the south end of runway. The pilot further reported he had landed and taken off from this airport previously without incident. The airport elevation was about 7,600 ft, and the runway was 1,800 ft long. The airplane owner's manual recommended a takeoff distance of 3,420 ft at 7,000 ft elevation and 40°F with zero wind velocity and from a hard level surface. The manual also stated that, under the most favorable condition of smooth, packed snow at 30°F, the takeoff distance for a ski-equipped airplane was about 10% greater than that for a wheel-equipped airplane. Per a supplemental type certificate (STC), the airplane underwent an engine conversion to a 180-horsepower, constant-speed propeller engine. No takeoff performance data were provided on the STC.
Factual narrative
The pilot of the ski-equipped airplane reported that he aborted his first attempt to take off, and during his second takeoff in a tailwind, shortly after rotation, the airplane settled back onto the snow-packed runway. He further reported that the airplane lifted off again, but about 5 feet above the ground and near the end of the runway, a wind gust pushed the airplane down onto the runway. The airplane overran the runway and the right wing impacted a tree. The wind direction and speed were not discernable due to the lack of a windsock or weather reporting station. The airplane sustained substantial damage to the wings. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot chose to depart to the north due to raising terrain and tall trees on south end of runway. The airport elevation was approximately 7,600 feet with the runway length of 1,800 feet. The airplane owner's manual performance information for zero wind velocity and hard level surface recommends 3,260 feet for take of distance at 7,000 feet elevation, 40 degrees F. and flaps in the up configuration. With flaps at 20 degrees, the owner's manual recommends 3,420 feet for take of distance at 7,000 feet elevation and 40 degrees F. The owner's manual also identifies performance information for a skiplane under the most favorable condition of smooth packed snow at temperatures of approximately 30 degrees F, the skiplane take-off distance is approximately 10% greater than that shown for the landplane. However, via the Supplimental Type Certificate (STC) process the airplane did undergo an engine conversion to the 180 hp and constant speed propeller. No take-off performance data was identified on the STC. The pilot further reported he had landed and taken-off from this airport previously without incident.
Aircraft
- Registration
- N4385B
- Reported as
- Cessna 170 (B)
- Category
- Airplane
- Serial number
- 26729
- Built
- 1956
- Airframe hours
- 6,729.8
- Engine
- Lycoming O-360-4A4, 180 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Positioning · Part 91
- Airworthiness certificate
- Special, Restricted (Special); Standard, Normal
- Last inspection
- Annual · August 29, 2018
- Departed
- KMYL · McCall, ID
- Destination
- PVT · Riggins, ID
- Flight plan
- Company VFR
- Airport
- PVT · Buffalo Hump (Concord) private, runway 01, 1,800 × 50 ft, snow
- Equipment
- Stall warning system
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
- 64
- Injuries
- None
- Certificates
- Flight instructor, Commercial
- Airplane ratings
- Single-engine sea, Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 2, With waivers/limitations
- Last flight review
- June 14, 2018
- Seat
- Front
- Restraint
- 3-point
- Flight hours
- 21,500 total · 2,000 in this make and model · 21,200 as pilot in command · 137 in the last 90 days · 15 in the last 30 days
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 290° at 8 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- 8,500 ft overcast
- Temperature
- 43 °F, dew point 28 °F
- Altimeter
- 29.97 inHg
- Observed at
- KGIC, 28 nm away
Docket · 2
The files NTSB released with the investigation on March 12, 2019, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.8 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.