# NTSB WPR23LA343: Boeing A75N1(PT17), N10KP, Monticello, UT, September 13, 2023 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: September 13, 2023, 11:00 local (17:00 UTC) - Place: Monticello, UT · Open field - Coordinates: 37.91356, -109.32524 - Nearby events: https://openairdocs.org/map.md?lat=37.9136&lon=-109.3252&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 193063 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA343 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193063/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193063 - Page: https://openairdocs.org/ntsb/WPR23LA343 ## Probable cause A partial loss of engine power for reasons that could not be determined. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined; cases with it: [Boeing A75N1(PT17), 8 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1380134), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Boeing A75N1(PT17), 2 cases](https://openairdocs.org/ntsb-events/000/sequence.md?model=1380134), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Boeing A75N1(PT17), 22 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1380134), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot departed the airport, conducted a low pass over the runway, and was climbing the airplane to pattern altitude when the engine began to lose power. The pilot stated that the engine did not lose complete power; however, the rpm and airspeed continued to decline and he chose to make a forced landing. The airplane landed in heavily vegetated terrain and during the landing roll the left main landing gear collapsed, resulting in substantial damage to the lower left wing. A postaccident examination of the airframe and engine revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. Although remnants of a high-temperature cloth were found between the air filter and particle screen, no debris was found in the filter or induction screen and the air intake did not appear to be impeded. Based on the available information, the reason for the loss of engine power could not be determined. ## Factual narrative On September 13, 2023, at 1100 mountain daylight time, a Boeing Stearman A75N1 (PT-17), N10KP, was substantially damaged when it was involved in an accident near Monticello, Utah. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, after performing the preflight checklist and engine run-up, he departed from runway 16 and remained in the airport traffic pattern. He conducted a low pass over the runway, made a left crosswind turn, and began a climb. About 500 ft above the ground, the engine began to lose power. The engine did not exhibit a complete loss of power, but engine rpm and airspeed continued to decline. The pilot chose to make a forced landing to flat, sage brush-covered terrain. The left main landing gear collapsed during the landing roll, resulting in substantial damage to the lower left wing when it struck the surface. Examination of the airframe and engine revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. Throttle and mixture control continuity was established from the rear cockpit controls to the engine. The fuel system was intact with no fuel leaks observed. The front spark plugs were removed, and the propeller was rotated by hand. Rotational continuity was established throughout the engine and valvetrain, and thumb compression was obtained for all 9 cylinders. The starter was engaged, and spark was obtained at all ignition leads. Removal of the induction system revealed remnants of a high-temperature cloth between the air filter and particle screen. No additional cloth debris was observed in the filter or induction screen. The carburetor remained secure at its mount and when the throttle was actuated by hand fuel was expelled from the accelerator pump port. The carburetor fuel screen was free of debris. The carburetor was removed and disassembled with no discrepancies noted. Fuel was obtained from the airframe fuel filter, carburetor, and fuel tank; all fuel samples were free of debris and blue in color. A review of the weather conditions reported by Blanding Municipal Airport (BDG), Blanding, Utah, about 21 nautical miles southwest of the accident site, indicated a temperature of 64.4°F, and a dew point of 50°F around the time of the accident. ## Aircraft - Registration: [N10KP](https://openairdocs.org/aircraft/N10KP), registered now, S/N 755247, built 1942 (OpenAirDocs) - Reported make and model: BOEING A75N1(PT17) - Registry model: [Boeing A75N1(PT17)](https://openairdocs.org/model/boeing-a75n1-pt17) (registry code 1380134) (OpenAirDocs) - Registry engine: [Lycoming R680](https://openairdocs.org/engine/lycoming-r680) (registry code 41540, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 755247 - Year built: 1942 - Airframe hours: 5833.7 - Engines: Lycoming R680-17 225 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 1, 2022, 7 hours before - Departed: U64, Monticello, UT - Destination: Same as departure - Airport: U64, Monticello - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; injuries: minor; private; airplane ratings: single-engine land; medical: basicmed, unknown; last flight review September 22, 2022; seat: rear; flight hours: 0 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 80° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 3,400 ft overcast - Temperature: 64 °F, dew point 50 °F - Altimeter: 30.20 inHg - Observed at: KBDG, 21 nm away - METAR: KBDG 131715Z AUTO 08006KT 10SM OVC034 18/10 A3020 RMK AO2 T01840098 ## 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 20230913015599A](https://openairdocs.org/incident/20230913015599A), Sep 13, 2023: Boeing A75N1(PT17), Monticello, UT, Substantial damage. September 9, 2023 near monticelc Utah a 1942 stearman aircraft completed the runup & check list, took off on runway 16, and remained in pattern, turned to… ## Docket (6 files) The files NTSB released with the investigation on March 5, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193063. 4.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16178844&FileExtension=pdf&FileName=WPR21LA343%206120_Redacted-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 2, PDF, 1 page, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17946240&FileExtension=pdf&FileName=DBieber%20RoC%20WPR23LA343-Rel.pdf - Exam report - NTSB (item 3, PDF, 3 pages, 412 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16705383&FileExtension=pdf&FileName=wpr23la343%20exam-Rel.pdf - FAA special airworthiness information bulletin (CE-09-35) carburetor icing prevention (item 4, PDF, 3 pages, 106 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16847072&FileExtension=pdf&FileName=r_CE-09-35-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 5, PDF, 2 pages, 124 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16488265&FileExtension=pdf&FileName=Retention-Release-of-Wreckage-Form%20N10KP_Redacted-Rel.pdf - Photos (item 6, PDF, 2 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16488739&FileExtension=pdf&FileName=photos-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. --- 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.