# NTSB GAA19CA098: Cessna 170, N4385B, Riggins, ID, December 16, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: December 16, 2018, 12:00 local (19:00 UTC) - Place: Riggins, ID - Coordinates: 45.58361, -115.681663 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.5836&lon=-115.6817&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 26, 2019 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 98778 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA19CA098 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98778/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98778 - Page: https://openairdocs.org/ntsb/GAA19CA098 ## 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 NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: climb rate](https://openairdocs.org/ntsb-findings/01062035): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 170B, 6 cases](https://openairdocs.org/ntsb-findings/01062035/cases.md?model=2072306), [All aircraft, 265 cases](https://openairdocs.org/ntsb-findings/01062035/cases.md) - [Object/animal/substance: tree(s)](https://openairdocs.org/ntsb-findings/03022020): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna 170B, 6 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md?model=2072306), [All aircraft, 933 cases](https://openairdocs.org/ntsb-findings/03022020/cases.md) - [Wind: tailwind](https://openairdocs.org/ntsb-findings/03034015): Environmental issues › Conditions/weather/phenomena · Response/compensation; cases with it: [Cessna 170B, 12 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md?model=2072306), [All aircraft, 594 cases](https://openairdocs.org/ntsb-findings/03034015/cases.md) - [Planning/preparation: performance calculations](https://openairdocs.org/ntsb-findings/02061010): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 170B, 2 cases](https://openairdocs.org/ntsb-findings/02061010/cases.md?model=2072306), [All aircraft, 114 cases](https://openairdocs.org/ntsb-findings/02061010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Cessna 170B, 12 cases](https://openairdocs.org/ntsb-events/400/sequence.md?model=2072306), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Cessna 170B, 19 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2072306), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Takeoff: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 170B, 52 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072306), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Takeoff: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Cessna 170B, 37 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=2072306), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## 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](https://openairdocs.org/aircraft/N4385B), registered now, S/N 26729, built 1956 (OpenAirDocs) - Reported make and model: Cessna 170 (B) - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 26729 - Year built: 1956 - Airframe hours: 6729.8 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 64; injuries: none; 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 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20181216022219A](https://openairdocs.org/incident/20181216022219A), Dec 16, 2018: Cessna 170B, Riggins, ID, Substantial damage. High altitude short field downwind take off, aircraft failed to climb clear of trees, struck trees in clearway,and descended abruptly, and nosed over in… ## Docket (2 files) The files NTSB released with the investigation on March 12, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98778. 3.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40470988&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photo (item 2, .PDF, 1 photo, 124 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40470989&FileExtension=.PDF&FileName=Accident%20Photo-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.