# NTSB WPR24LA271: Piper PA-18-150, N8576Y, Manhattan, MT, August 11, 2024

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: August 11, 2024, 10:34 local (16:34 UTC)
- Place: Manhattan, MT · 1/2 way between BZN and 9S5
- Coordinates: 45.823782, -111.34711 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.8238&lon=-111.3471&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Adminstration
- NTSB case key (mKey): 194908
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA271
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194908/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194908
- Page: https://openairdocs.org/ntsb/WPR24LA271

## Probable cause

A total loss of engine power due to carburetor icing.

## 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 operation (probable cause); cases with it: [Piper PA-18-150, 15 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=7101828), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md)

## Sequence of events

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

- [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Piper PA-18-150, 18 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7101828), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Enroute: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Piper PA-18-150, 18 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=7101828), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md)
- [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-18-150, 15 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7101828), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Piper PA-18-150, 83 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=7101828), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)
- [Post-impact: Evacuation](https://openairdocs.org/ntsb-events/460); cases with it: [Piper PA-18-150, 1 case](https://openairdocs.org/ntsb-events/460/sequence.md?model=7101828), [All aircraft, 103 cases](https://openairdocs.org/ntsb-events/460/sequence.md)

## Analysis

The instructor pilot was giving dual instruction to a pilot-rated student. He reported that soon after departure, the airplane engine RPM reduced to idle. The pilot verified the throttle was at full power, adequate fuel was in both tanks and subsequently applied carburetor heat, which restored the engine to full power. After 10 seconds the RPM began surging and the pilot then turned the carburetor heat off. He turned the carburetor heat on again and pumped the throttle repeatedly while the power continued to surge until the engine quit and he lost all power. They were unable to restart the engine and landed the airplane in a nearby agricultural field. The airplane came to rest inverted, which resulted in substantial damage to the vertical stabilizer. The engine ran normally on the ground after the airplane was returned to its upright position following the accident. When the temperature and the dewpoint near the time of the accident were plotted on a carburetor icing probability graph, it was revealed that the airplane was likely operating in meteorological conditions conducive to the formation of carburetor icing (for glide power settings). The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

## Aircraft

- Registration: [N8576Y](https://openairdocs.org/aircraft/N8576Y), registered now, S/N 18-8889 (OpenAirDocs)
- Reported make and model: PIPER PA-18-150
- Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 18-8889
- Year built: 1976
- Airframe hours: 4477.7
- Engines: LYCOMING O-320 SERIES 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Registered owner: Ridgeline Aviation Inc
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 5, 2024, 28.8 hours before
- Airport: BZN, Bozeman Yellowstone Intl
- Equipment: Electronic flight bag or handheld device, ADS-B, Angle of attack indicator

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 29; injuries: none; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review July 1, 2024; seat: rear; restraint: 3-point; flight hours: 544 total, 293 in this make and model, 443 as pilot in command, 80 in the last 90 days, 36 in the last 30 days, 1 in the last 24 hours
- Pilot; age 21; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; last flight review May 3, 2024; seat: front; restraint: 3-point; flight hours: 220 total, 5 in this make and model, 154 as pilot in command, 7 in the last 90 days, 4 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point 52 °F
- Altimeter: 30.17 inHg
- Observed at: KBZN, 8 nm away
- METAR: METAR KBZN 111656Z 00000KT 10SM CLR 18/11 A3017 RMK AO2 SLP193 T01830111=

## 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 20240811010309A](https://openairdocs.org/incident/20240811010309A), Aug 11, 2024: Piper PA-18-150, Bozeman, MT, Substantial damage. Aircraft experienced a power loss during climb, unable to correct the problem utilizing the checklist procedures. Carb heat applied and on duration of…

## Other investigations on N8576Y (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 CEN10CA473](https://openairdocs.org/ntsb/CEN10CA473), Aug 5, 2010: Piper PA-18-150 (N8576Y), Watkins, CO, substantial damage. Probable cause: The pilot's failure to maintain aircraft control during the landing, resulting in a ground-loop.

## Docket (8 files)

The files NTSB released with the investigation on February 27, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194908. 52.4 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17570757&FileExtension=pdf&FileName=6120%20WPR24LA271%20Manhattan,%20MT%20N8576Y%20Pilot_Redacted-Rel.pdf
- Pilot student aircraft accident report, NTSB form 6120.1 (item 2, PDF, 11 pages, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17725442&FileExtension=pdf&FileName=Pilot%20student%206120_Redacted-Rel.pdf
- Photo (item 3, PDF, 1 page, 298 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17571062&FileExtension=pdf&FileName=Photo%20WPR24LA271%20Manhattan,%20MT%20N8576Y-Rel.pdf
- Most recent maintenance records (item 4, PDF, 6 pages, 264 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17726359&FileExtension=pdf&FileName=N8576%20Maint%20and%20AD%20compliance_Redacted-Rel.pdf
- Memorandum for record a�� telephone interview, wx witness pilot (item 5, PDF, 1 page, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17727447&FileExtension=pdf&FileName=MOR%20Icing%20interview%20Nonaccident%20pilot-Rel.pdf
- FAA special airworthiness information bulletin - carburetor icing prevention (item 6, PDF, 3 pages, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17724510&FileExtension=pdf&FileName=CE-09-35-Rel.pdf
- Piper aircraft - PA-18-150 owner's handbook excerpt (item 7, PDF, 3 pages, 309 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17727170&FileExtension=pdf&FileName=PA18_150_Sec_3%20pg18_19%20Operating%20instructions%20severe%20carburetor%20icing-Rel.pdf
- Video recovery mechanic engine run (item 8, MP4, 47.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17730867&FileExtension=mp4&FileName=20240811_213450000_iOS-Rel.mp4

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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