# NTSB WPR18LA176: Piper PA 18-150, N1979P, Yellow Pine, ID, June 21, 2018

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Class 3 · Limited · Final report
- Date: June 21, 2018, 12:00 local (18:00 UTC)
- Place: Yellow Pine, ID
- Coordinates: 45.1492, -115.0773
- Nearby events: https://openairdocs.org/map.md?lat=45.1492&lon=-115.0773&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Defining event: [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 97550
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR18LA176
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97550/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97550
- Page: https://openairdocs.org/ntsb/WPR18LA176

## Probable cause

The pilot’s failure to maintain adequate airspeed while conducting a go-around and his exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall/spin at too low of an altitude to recover. Contributing to the accident were the pilot’s lack of preflight planning, including his failure to obtain a briefing on the challenging, one-way airstrip, and his unfamiliarity with operating into and out of the airstrip, which was surrounded by mountainous terrain.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Planning/preparation: flight planning/navigation](https://openairdocs.org/ntsb-findings/02061025): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-18-150, 4 cases](https://openairdocs.org/ntsb-findings/02061025/cases.md?model=7101828), [All aircraft, 179 cases](https://openairdocs.org/ntsb-findings/02061025/cases.md)
- [Knowledge: knowledge of procedures](https://openairdocs.org/ntsb-findings/02032010): Personnel issues › Experience/knowledge · Pilot (probable cause); cases with it: [Piper PA-18-150, 1 case](https://openairdocs.org/ntsb-findings/02032010/cases.md?model=7101828), [All aircraft, 41 cases](https://openairdocs.org/ntsb-findings/02032010/cases.md)
- [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Piper PA-18-150, 51 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=7101828), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md)
- [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Piper PA-18-150, 24 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=7101828), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md)
- [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-18-150, 160 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7101828), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)
- [Terrain: mountainous/hilly terrain](https://openairdocs.org/ntsb-findings/03021010): Environmental issues › Physical environment · Decision related to condition (probable cause); cases with it: [Piper PA-18-150, 5 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md?model=7101828), [All aircraft, 329 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Piper PA-18-150, 41 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7101828), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md)
- [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-18-150, 115 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7101828), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

The private pilot was conducting a personal, cross-country flight as part of a flight of three. One of the pilots reported that, as the flight of three approached the one-way-in, 700-ft-long remote mountain airstrip, the lead pilot surveyed the area, and he reported that no other airplanes were in the area. Subsequently, he and the lead pilot landed at the airstrip uneventfully. After landing, he parked his airplane at the top of the airstrip facing directly down the runway, which allowed him to easily see the approach path to the airstrip. As he was waiting for the accident airplane to come into view, he asked the accident pilot “…you’ve been in here before, right”? The accident pilot replied that he had not, and the other pilot then reminded the accident pilot to fly “low over the creek.” He added that, when the accident airplane came into view, it was higher than the lead airplane had been on its approach. When the accident airplane had almost reached the extended runway centerline, the accident pilot added power, after which, the airplane pitched up steeply. The airplane then continued upstream of a nearby creek for about 1/2 mile with the nose up and “not climbing well, if at all.” The airplane then entered a left turn, followed by the left-wing dipping and the airplane entering a left spin. The pilot stated that he saw the airplane make 1 1/4 rotations before it descended out of his sight and impacted terrain and that the engine sounded like it was developing full power from the time of the initial go-around until impact. The pilot’s brother and one of the pilots who witnessed the accident reported that there were no preaccident mechanical malfunctions or failures with the airplane or engine that would have precluded normal operation. The pilot does not recall the events leading to the accident. Therefore, based on the available information, it is likely that the pilot failed to maintain adequate airspeed and exceeded the airplane’s critical angle of attack during the go-around, which resulted in an aerodynamic stall/spin at too low of an altitude to recover. The accident flight was the accident pilot’s first attempt to land at the airstrip, which is confined by mountainous terrain and requires pilots to land one way and depart the other with virtually no go-around options during the approach. A plan view of the airstrip recommended that it “be used only by mountain proficient pilots who have had a checkout specific to the airstrip.” In an Aircraft Owners and Pilots Association video made after the accident pilot recovered from his injuries, he stated that he was negligent in planning for the flight, which included not having obtained a briefing on the airstrip. The pilot also mentioned his lack of proficiency at the time of the accident. Therefore, contributing to the accident were the pilot’s failure to obtain a briefing on the airstrip, lack of planning for the flight, and unfamiliarity with the airstrip.

## Factual narrative

On June 21, 2018, about 1200 mountain daylight time, a Piper PA-18-150 airplane, N1979P, was substantially damaged when it was involved in an accident near Yellow Pine, Idaho. The pilot was seriously injured. The airplane was being operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The accident airplane was a part of a flight of three, which had departed Cabin Creek US Forest Service Airport (I08), Big Creek Ranger Station, Idaho, for Dewey Moore Airstrip, Cascade, Idaho, which is a remote, mountainous, backcountry airstrip. One of the pilots in the flight of three reported that, as they approached the Dewey Moore Airstrip, the lead airplane pilot surveyed the area, and he reported that there was no other traffic. Subsequently, he and the lead pilot landed uneventfully, and he noted that “the conditions were excellent, with calm air, and the runway in good condition”; he had landed there the previous day. He then parked his airplane at the top of the airstrip facing directly down the runway, which allowed him to easily see the approach to the airstrip. As he was waiting for the accident airplane to come into view, he asked him, “…you’ve been in here before, right”? The accident pilot replied that he had not. He then reminded the accident pilot to fly “low over the creek” and added that, when the accident airplane came into view, it was higher than the lead airplane had been on its approach. When the accident airplane had almost reached the extended runway centerline, the accident pilot added power, after which, the airplane pitched up steeply. It then continued flying upstream of a nearby creek for about 1/2 mile with the nose up and “not climbing well, if at all.” The airplane then entered a left turn away from his position and directly over the creek. Subsequently, the left wing dipped, and the airplane entered a left spin. The pilot stated that he then saw the airplane make 1 1/4 left rotations before it descended out of his sight and impacted terrain. He added that the engine sounded like it was developing full power from the time of the initial go-around until impact. The wreckage came to rest on sloping terrain. The airframe and wings were substantially damaged. The pilot’s brother and one of the pilots who witnessed the accident reported that there were no preaccident mechanical malfunctions or failures with the airplane or engine that would have precluded normal operation. The pilot does not recall the events leading to the accident. Dewey Moore Airstrip is located at 4,494 ft mean sea level. The single gravel runway, 28/10, is a one-way in, one-way out airstrip: airplanes landed on runway 28 and departed from runway 10. The remarks section of the plan view of the airstrip recommended that it be used “only by mountain proficient pilots who have had a checkout specific to the airstrip.” In an Aircraft Owners and Pilots Association video made after the pilot had recovered from his injuries, the pilot stated that hewas negligent in planning for the flight, which included not obtaining a briefing on the airstrip. The pilot also mentioned his lack of proficiency at the time of the accident.

## Aircraft

- Registration: [N1979P](https://openairdocs.org/deregistered/N1979P-2021-01-09), registration cancelled 2021-01-09, S/N 18-4214, built 1955 (OpenAirDocs)
- Reported make and model: PIPER PA 18-150 (150)
- Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs)
- Registry engine: [Lycoming O-360-C4P](https://openairdocs.org/engine/lycoming-o-360-c4p) (registry code 42289, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 18-4214
- Year built: 1955
- Airframe hours: 5114
- Engines: LYCOMING O-360-C4P 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Simmons W Todd
- Registered owner: Simmons W Todd
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, February 12, 2018
- Departed: na, Cascade, ID
- Destination: na, Yellow Pine, ID
- Airport: na, Dewey Moore Airstrip, runway 10, 700 × 30 ft, gravel
- Equipment: Electronic primary flight display, Handheld GPS, Onboard weather, Stall warning system, ADS-B, Electronic flight bag or handheld device, Electronic multifunction display

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; injuries: serious; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: front; restraint: 4-point; flight hours: 2,101 total, 600 in this make and model, 55 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 310° at 6 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point 52 °F
- Altimeter: 30.09 inHg
- Observed at: MYL, 46 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 20180621015619A](https://openairdocs.org/incident/20180621015619A), Jun 21, 2018: Piper PA-18-150, Yellow Pine, ID, Substantial damage. Pilot was attempting to land at a airstrip he has never been into before. This strip is limited to highly experienced mountain pilots. His approach was high…

## Other investigations on N1979P (1)

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.

- [NTSB DEN71DXA21](https://openairdocs.org/ntsb/DEN71DXA21), Apr 12, 1971: Piper PA-18 (N1979P), Seely, WY, destroyed

## Docket (8 files)

The files NTSB released with the investigation on May 12, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97550. 7.6 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12143170&FileExtension=pdf&FileName=NTSB%20pilot%20accident%20report%20form_Redacted-Rel.pdf
- Witness statement (item 2, PDF, 1 page, 210 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12143674&FileExtension=pdf&FileName=Witness%20statement_Redacted-Rel.pdf
- Accident site maps (item 3, PDF, 3 pages, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12142475&FileExtension=pdf&FileName=Accident%20site%20maps-Rel.pdf
- Dewey moore airstrip map (item 4, PDF, 1 page, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12146762&FileExtension=pdf&FileName=Dewey%20Moore%20Airstrip%20map-Rel.pdf
- Evidence control form (item 5, PDF, 1 page, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12143584&FileExtension=pdf&FileName=Evidence%20Control%20form%20%20-%20maintenance%20records_Redacted-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 6, PDF, 1 page, 147 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12143423&FileExtension=pdf&FileName=NTSB%20Release%20of%20Wreckage%20form_Redacted-Rel.pdf
- Photo array - onsite photos (item 7, PDF, 3 pages, 178 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12143953&FileExtension=pdf&FileName=Photo%20array%20of%20airplane%20at%20rest%20at%20accident%20site-Rel.pdf
- Aopa video - a lesson from the backcountry - a no-go around (item 8, PDF, 1 page, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12147549&FileExtension=pdf&FileName=AOPA%20video%20link%20-%20A%20lesson%20from%20the%20backountry%20-%20no%20Go-Around-Rel.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.

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