# NTSB WPR21LA212: Maule M-5-235C, N9254E, Stanley, ID, May 29, 2021

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: May 29, 2021, 11:00 local (17:00 UTC)
- Place: Stanley, ID · Mountainous terrain of felled trees
- Coordinates: 44.67962, -115.01661
- Nearby events: https://openairdocs.org/map.md?lat=44.6796&lon=-115.0166&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR go-around: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs)
- NTSB case key (mKey): 103183
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA212
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103183/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103183
- Page: https://openairdocs.org/ntsb/WPR21LA212

## Probable cause

The pilot’s failure to use carburetor heat in weather conditions conducive to carburetor icing, resulting in a partial loss of engine power and a forced landing during which the airplane struck an object and nosed over.

## Findings

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

- [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Maule M-5-235C, 1 case](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=5460135), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md)
- [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Maule M-5-235C, 1 case](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=5460135), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md)
- [Ice/rain protection system: intake anti-ice, deice](https://openairdocs.org/ntsb-findings/01023020): Aircraft › Aircraft systems · Not used/operated (probable cause); cases with it: [Maule M-5-235C, 1 case](https://openairdocs.org/ntsb-findings/01023020/cases.md?model=5460135), [All aircraft, 108 cases](https://openairdocs.org/ntsb-findings/01023020/cases.md)

## Sequence of events

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

- [Approach-VFR go-around: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Maule M-5-235C, 2 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=5460135), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Initial climb: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Maule M-5-235C, 6 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=5460135), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-flare/touchdown: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Maule M-5-235C, 18 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=5460135), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The pilot initiated a descent to the remote airstrip with the intention of performing a low approach to check the runway surface then landing if conditions allowed. About 500 ft before the runway threshold, the pilot applied full engine power, and the engine responded but then began to progressively lose power. He turned on the carburetor heat, confirmed that the engine mixture was set correctly, and began to turn the airplane away from rising terrain. The airplane would not climb, and he maneuvered it through an adjacent canyon, at which time the engine started to regain power. Due to rising terrain, the pilot had limited options to turn around the airplane, so the pilot performed a forced landing. During the landing flare, the airplane struck a log and nosed over. Postaccident examination revealed no anomalies with the engine that would have precluded normal operation. Weather conditions at the time of the flight were conducive to serious carburetor icing at cruise power. The pilot did not turn on carburetor heat until after the engine started to lose power, so it is likely that pilot’s failure to use carburetor heat earlier in the flight caused carburetor icing that led to the partial loss of engine power.

## Factual narrative

On May 29, 2021, about 1100 mountain daylight time, a Maule M-5-235C, N9254E, was substantially damaged when it was involved in an accident near Thomas Creek Airport (2U8), Stanley, Idaho. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 flight. The pilot reported that the airplane’s takeoff and climb from Johnson Creek Airport (3U2), Yellow Pine, Idaho, about 30 minutes before the accident, was uneventful. When the airplane reached an altitude of about 10,000 ft mean sea level (msl), the pilot reduced engine power and initiated a descent to 2U8, with the intention of performing a low approach to check the runway surface then landing if conditions allowed. About 500 ft before the runway threshold, the pilot applied full engine power, and the engine responded but then began to progressively lose power. He turned on the carburetor heat, confirmed that the engine mixture was set correctly, and began to turn the airplane away from rising terrain at the end of the runway. The airplane would not climb, and the pilot maneuvered the airplane through a neighboring canyon, at which time the engine started to regain power. The pilot continued to assess the surrounding terrain and decided that he would not be able to safely turn the airplane around. He then observed a flat area and maneuvered the airplane to that spot to perform a forced landing at the lowest possible airspeed. During the landing flare, the airplane struck a log and nosed over. Postaccident examination revealed no anomalies with the engine that would have precluded normal operation. The closest official weather observation station, located at McCall Municipal Airport, McCall, Idaho, indicated a temperature and a dew point temperature of about 44.5°F and 37.5 F, respectively, about the time of the accident. According to Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35, Carburetor Icing Prevention, such conditions were conducive to serious carburetor icing at cruise power.

## Aircraft

- Registration: [N9254E](https://openairdocs.org/aircraft/N9254E), registered now, S/N 7147C (OpenAirDocs)
- Reported make and model: MAULE M-5-235C
- Registry model: [Maule M-5-235C](https://openairdocs.org/model/maule-m-5-235c) (registry code 5460135) (OpenAirDocs)
- Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 7147C
- Year built: 1977
- Airframe hours: 1769.2
- Engines: LYCOMING O-540 235 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, March 2, 2021, 130.8 hours before
- Departed: 3U2, Johnson Creek Airport, ID
- Destination: Same as departure
- Airport: 2U8, Thomas Creek, runway 21, 2,100 × 75 ft, grass/turf
- Equipment: ADS-B

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review November 28, 2020; seat: left; restraint: 3-point; flight hours: 349 total, 185 in this make and model, 349 as pilot in command, 188 in the last 90 days, 88 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: 2,000 ft overcast
- Temperature: 45 °F, dew point 37 °F
- Altimeter: 30.18 inHg
- Observed at: KMYL, 48 nm away
- METAR: SPECI KMYL 261716Z AUTO 00000KT 10SM SCT013 OVC020 07/03 A3018 RMK AO2 T00720033

## 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 20210529007089A](https://openairdocs.org/incident/20210529007089A), May 29, 2021: Maule M-5-235C, Stanley, ID, Substantial damage. [privacy data omitted] Stated that after a low approach (fly over) the engine started losing power. Pilot in command (PIC) applied carburetor heat with no…

## Docket (5 files)

The files NTSB released with the investigation on November 22, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103183. 3.2 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14260028&FileExtension=pdf&FileName=r_6120_Redacted-Rel.pdf
- Engine examination (item 2, PDF, 1 page, 61 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14259953&FileExtension=pdf&FileName=Exam%20Notes%20N9254E-Rel.pdf
- FAA SAIB CE-09-35 (item 3, PDF, 3 pages, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14259654&FileExtension=pdf&FileName=CE-09-35-Rel.pdf
- Release of aircraft wreckage, NTSB form 6120.15 (item 4, PDF, 1 page, 372 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14260038&FileExtension=pdf&FileName=r_Release-of-Wreckage-WPR21LA212_Redacted-Rel.pdf
- Photo of accident site (item 5, PDF, 1 page, 722 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14260267&FileExtension=pdf&FileName=Photo-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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