WPR18LA176

NTSB accident investigation · Piper PA 18-150 · Yellow Pine, ID · June 21, 2018

Accident · Serious injuriesClass 3 · LimitedFinal report
Date
June 21, 2018, 12:00 local (18:00 UTC)
Place
Yellow Pine, ID
Injuries
1 serious
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N1979PPiper PA 18-150
Defining event
Maneuvering-low-alt flying: Loss of control in flight
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Western Pacific Region
Parties
Federal Aviation Administration
FAA report
20180621015619A
Case key
97550

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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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 · 6

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.

Knowledge: knowledge of proceduresPersonnel issues › Experience/knowledge · PilotPiper PA-18-150: 1 caseAll aircraft: 41 casesProbable cause
Performance/control parameters: airspeedAircraft › Aircraft oper/perf/capability · Not attained/maintainedPiper PA-18-150: 24 casesAll aircraft: 1,681 casesProbable cause
Use of equip/info: aircraft controlPersonnel issues › Task performance · PilotPiper PA-18-150: 160 casesAll aircraft: 9,295 casesProbable cause
Terrain: mountainous/hilly terrainEnvironmental issues › Physical environment · Decision related to conditionPiper PA-18-150: 5 casesAll aircraft: 329 casesProbable cause

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 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
Reported as
Piper PA 18-150 (150)
Category
Airplane
Serial number
18-4214
Built
1955
Airframe hours
5,114
Engine
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

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
49
Injuries
Serious
Certificate
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

Docket · 8

The files NTSB released with the investigation on May 12, 2021, on NTSB’s docket system: statements, records, photos and specialists’ reports. 7.6 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.

Other investigations on N1979P · 1

Matched to the same aircraft by N-number and date.