# NTSB ANC13CA044: Piper PA-18-150, N8899Y, Palmer, AK, May 7, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 7, 2013, 13:45 local (21:45 UTC) - Place: Palmer, AK - Coordinates: 61.95, -149.216659 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.9500&lon=-149.2167&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 29, 2013 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA FSDO - NTSB case key (mKey): 86894 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC13CA044 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86894/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86894 - Page: https://openairdocs.org/ntsb/ANC13CA044 ## Probable cause The pilot's failure to use continuous carburetor heat while operating in conditions conducive to carburetor icing, which resulted in the development of carburetor ice and a subsequent partial loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-18-150, 20 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=7101828), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) - [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-cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Piper PA-18-150, 13 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=7101828), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Piper PA-18-150, 13 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=7101828), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing-landing roll: 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) ## Analysis The pilot reported that while in level cruise flight, the engine began to run rough and lost power. Unable to restore full engine power, the pilot selected an area of snow-covered terrain as a forced landing site. During the landing, as the main wheels contacted deep snow, the airplane nosed over, sustaining substantial damage to the right wing lift strut. The pilot reported that he applied carburetor heat after the initial loss of engine power and that the engine was only able to maintain 1,100 rpm. About the time of the accident, a weather observation station located about 25 miles northwest of the accident site reported the temperature at 45 degrees F and dew point at 41 degrees F. According to a carburetor icing probability chart, the airplane was susceptible to icing at both cruise and climb power. The pilot did not report and a postaccident examination of the wreckage did not reveal any evidence of a mechanical malfunction. It is likely that the loss of engine power was due to carburetor icing. ## Factual narrative The pilot reported that while in level cruise flight, the engine began to run rough and lose power. Unable to restore full engine power, he selected an area of snow-covered terrain as a forced landing site. During the forced landing, as the main wheels contacted deep snow, the airplane nosed over, sustaining substantial damage to the right wing lift strut. The pilot noted in his written report to the NTSB that carburetor heat was applied after the initial loss of engine power, and that he was only able to maintain 1,100 engine rpm before the forced landing. At time of the accident a weather observation station located about 25 miles northwest of the accident site was reporting, in part: temperature, 45 degrees F; dew point, 41 degrees F. When the temperature and dew point are entered into a carburetor icing probability chart, the result is in the "Icing-cruise or climb power" category. A Federal Aviation Administration (FAA) airworthiness inspector from the Anchorage Flight Standards District Office traveled to the pilot's private airstrip, and examined the airplane after it was recovered. The inspector reported that he was unable to find any preaccident mechanical problems with the airplane. During a subsequent follow-up conversation, the pilot reported that there were no preaccident mechanical anomalies with the airplane, and given the temperature and dew point at the time of the accident, the loss of engine power was likely due to carburetor icing. ## Aircraft - Registration: [N8899Y](https://openairdocs.org/aircraft/N8899Y), registered now, S/N 18-7409031, built 1974 (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 O-320-A2B](https://openairdocs.org/engine/lycoming-o-320-a2b) (registry code 42101, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-7409031 - Engines: LYCOMING O-320-A2B 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Westcott Brett M - Registered owner: Westcott Brett M - Airworthiness certificate: Standard, Normal - Departed: 6AK7, Wasilla, AK - Destination: 6AK7, Wasilla, AK - Flight plan: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: none; airline transport; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, without waivers/limitations; seat: front; flight hours: 7,000 total, 520 in this make and model ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: 5,500 ft overcast - Temperature: 46 °F, dew point 27 °F - Altimeter: 30.25 inHg - Observed at: PAAQ, 25 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 20130507008789A](https://openairdocs.org/incident/20130507008789A), May 7, 2013: Piper PA-18-150, Willow, AK, Substantial damage. The pilot reported he was flying north of Willow Alaska when his engine lost power. He turned into the wind and made a forced landing. When the aircraft… ## Docket (3 files) The files NTSB released with the investigation on May 30, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86894. 3.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40393317&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation - Pilot (item 2, .PDF, 65 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40393406&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Pilot-Master.PDF - Carburetor Icing Chart (item 3, .PDF, 174 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40393318&FileExtension=.PDF&FileName=Carburetor%20Icing%20Chart-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.