# NTSB WPR11CA072: Piper PA-18-150, N4100Z, Pullman, WA, December 4, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: December 4, 2010, 14:00 local (22:00 UTC) - Place: Pullman, WA - Coordinates: 46.659999, -117.18 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.6600&lon=-117.1800&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Fuel related](https://openairdocs.org/ntsb-events/190) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 12, 2011 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Spokane FSDO - NTSB case key (mKey): 77936 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11CA072 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77936/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77936 - Page: https://openairdocs.org/ntsb/WPR11CA072 ## Probable cause The pilot's delayed application of carburetor heat while maneuvering, which resulted in a partial loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Piper PA-18-150, 11 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=7101828), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md) - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; 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) - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Response/compensation (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. - [Maneuvering-low-alt flying: Fuel related](https://openairdocs.org/ntsb-events/190) (defining event); cases with it: [Piper PA-18-150, 6 cases](https://openairdocs.org/ntsb-events/190/sequence.md?model=7101828), [All aircraft, 361 cases](https://openairdocs.org/ntsb-events/190/sequence.md) ## Analysis The pilot was maneuvering the airplane at a low altitude over open, snow-covered terrain, and noticed that the engine was beginning to lose power and running roughly. The airplane was starting to lose altitude and in response, he applied the carburetor heat and added full engine power. Just as the engine started to regain power, the main landing gear broke through the crusty top layer of the snow, slowing the airplane. The propeller contacted the snow and the pilot decreased the engine power and attempted to transition to a landing. The airplane nosed over inverted, resulting in substantial damage to the vertical stabilizer and both left wing lift struts. According to the pilot, with the exception of the accumulation of carburetor ice, there were no mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation. ## Factual narrative The pilot, who was chasing coyotes at low level over open snow-covered terrain, noticed that the airplane's engine was beginning to lose power and run rough, and that the airplane was starting to lose altitude. He therefore applied carburetor heat and full power, but just as the engine started to regain power, the airplane's main wheels broke through the crusty top layer of the snow. The airplane then began to slow, and when its propeller contacted the snow, the pilot pulled the power back and attempted to transition to a landing. Although the pilot had the control stick all the way back, the airplane nosed over onto its back, resulting in damage to the vertical stabilizer and the bending of both left wing lift struts. According to the pilot, except for the accumulation of carburetor ice, there were no problems with the engine. ## Aircraft - Registration: [N4100Z](https://openairdocs.org/aircraft/N4100Z), registered now, S/N 18-8114 (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: 18-8114 - Engines: LYCOMING O-320 SERIES 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Keith M. Kopf - Registered owner: Mountain Escape LLC - Airworthiness certificate: Standard, Normal - Departed: KPUW, Pullman, WA - Destination: KPUW, Pullman, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: none; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, without waivers/limitations; flight hours: 1,315 total, 760 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 80° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 30 °F ## 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 20101204052369A](https://openairdocs.org/incident/20101204052369A), Dec 4, 2010: Piper PA-18-150, Pullman, WA, Substantial damage. On December 4, 2010 at 14:00 hours local time N4100Z, a 1964 PA-18-150 received substantial damage as the result of landing in deep snow during off field… ## Other investigations on N4100Z (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 GAA19CA159](https://openairdocs.org/ntsb/GAA19CA159), Mar 9, 2019: Piper PA18 (N4100Z), Pullman, WA, substantial damage. Probable cause: The pilot's selection of unsuitable terrain for landing, which resulted in a nose-over. ## Docket (2 files) The files NTSB released with the investigation on December 20, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77936. 504 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 490 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40340576&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Narrative History of Flight (item 2, .PDF, 14 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40340577&FileExtension=.PDF&FileName=Narrative%20History%20of%20Flight-Redacted.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.