# NTSB CEN25LA168: Cessna 172N, N75775, Longmont, CO, May 4, 2025 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: May 4, 2025, 12:00 local (18:00 UTC) - Place: Longmont, CO · open field - Coordinates: 40.174833, -105.1875 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.1748&lon=-105.1875&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: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA Flight Standards - NTSB case key (mKey): 200108 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN25LA168 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/200108/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=200108 - Page: https://openairdocs.org/ntsb/CEN25LA168 ## Probable cause The disconnected throttle control that resulted in a loss of engine power due to improper maintenance. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine controls: power lever](https://openairdocs.org/ntsb-findings/01057603): Aircraft › Aircraft power plant · Inoperative (probable cause); cases with it: [Cessna 172N, 1 case](https://openairdocs.org/ntsb-findings/01057603/cases.md?model=2072434), [All aircraft, 95 cases](https://openairdocs.org/ntsb-findings/01057603/cases.md) - [Engine controls: power lever](https://openairdocs.org/ntsb-findings/01057603): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Cessna 172N, 1 case](https://openairdocs.org/ntsb-findings/01057603/cases.md?model=2072434), [All aircraft, 95 cases](https://openairdocs.org/ntsb-findings/01057603/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 172N, 5 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=2072434), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/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: [Cessna 172N, 23 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2072434), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172N, 31 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072434), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Cessna 172N, 44 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2072434), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The student pilot stated that he was on final approach when he noticed that the engine was not responding to his throttle control changes. The engine speed was about 2,000 rpm when he attempted a go-around; however, the engine power did not increase as he applied full throttle, and the airplane would not climb due to the low power setting. The student noted that the engine subsequently lost power completely and he executed a forced landing to a field. During the landing, the airplane struck a fence and nosed over. The airframe sustained substantial damage to the right wing, vertical stabilizer, and rudder. A post-accident examination determined that the throttle cable was disconnected from the carburetor. Both the throttle cable and the carburetor control arm moved freely and there was no evidence of damage to either component. The connecting hardware – bolt and nut – were not observed at the time of the examination. Airplane maintenance records revealed that a 100-hour inspection was completed three weeks before the accident, and the engine carburetor was replaced at that time. The airplane had accumulated about 9.9 hours flight time since that maintenance work. The mechanic stated that an apprentice had replaced the carburetor and the mechanic had gotten busy with other tasks and did not fully inspect the apprentice’s work. ## Factual narrative On May 4, 2025, about 1200 mountain daylight time, a Cessna 172N airplane, N75775, was substantially damaged when it was involved in an accident near Longmont, Colorado. The student pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The student pilot stated that he was on final approach when he noticed that the engine was not responding to his throttle control changes. The engine speed was about 2,000 rpm when he attempted a go-around. However, the engine power did not increase as he applied full throttle, and the airplane would not climb due to the low power setting. He noted that the engine subsequently lost power completely and he executed a forced landing to a field. During the landing, the airplane struck a fence and nosed over. The airframe sustained substantial damage to the right wing, vertical stabilizer, and rudder. A post-accident examination conducted by a Federal Aviation Administration inspector determined that the throttle cable was disconnected from the carburetor. Both the throttle cable and the carburetor control arm moved freely and there was no evidence of damage to either component. The connecting hardware – bolt and nut – were not observed at the time of the examination. Airplane maintenance records revealed that a 100-hour inspection was completed three weeks before the accident, and the engine carburetor was replaced at that time. The airplane had accumulated about 9.9 hours flight time since that maintenance. The mechanic noted that an apprentice had replaced the carburetor. He had gotten busy with other tasks and did not fully inspect the apprentice’s work. ## Aircraft - Registration: [N75775](https://openairdocs.org/aircraft/N75775), registered now, S/N 17267941, built 1976 (OpenAirDocs) - Reported make and model: CESSNA 172N - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17267941 - Year built: 1976 - Airframe hours: 14115.7 - Engines: LYCOMING O-320-H2AD 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Western Air Flight Academy, doing business as N/A - Registered owner: Rocky Mountain Aircraft Services LLC - Airworthiness certificate: Standard, Normal; Standard, Utility - Last inspection: 100 hour, April 28, 2025, 9.9 hours before - Departed: BJC, Broomfield, CO - Destination: LMO, Longmont, CO - Airport: LMO, Vance Brand, runway 29, 4,799 × 75 ft, concrete - Equipment: ADS-B, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; student; medical: class 1, without waivers/limitations; last flight review May 4, 2025; seat: left; restraint: 3-point; flight hours: 93.3 total, 93.3 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 37 °F - Altimeter: 29.89 inHg - Observed at: KLMO - METAR: METAR KLMO 041755Z AUTO 34005KT 10SM CLR 21/03 A2989 ## 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 20250504005309A](https://openairdocs.org/incident/20250504005309A), May 4, 2025: Cessna 172N, Longmont, CO, Substantial damage. On 05/04/2025 at approximately (11:43), (MDT), Cessna 172, Vance Brand Airport, Longmont, CO., (klmo), on final for runway 29, aircraft engine RPM would not… ## Docket (5 files) The files NTSB released with the investigation on September 3, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=200108. 10.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 4.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18767000&FileExtension=pdf&FileName=Accident%20Report%20--%20CEN25LA168_redacted-Rel.pdf - Investigation photographs (item 2, PDF, 4 pages, 701 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18767847&FileExtension=pdf&FileName=Investigation%20Photos%20--%20CEN25LA168-Rel.pdf - FAA inspector statements (item 3, PDF, 2 pages, 74 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19147136&FileExtension=pdf&FileName=FAA%20Inspector%20Statements-Rel.pdf - Maintenance records -- airframe (item 4, PDF, 2 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18767694&FileExtension=pdf&FileName=Maintenance%20Records%20--%20Airframe_redacted-Rel.pdf - Maintenance records -- engine (item 5, PDF, 5 pages, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18767512&FileExtension=pdf&FileName=Maintenance%20Records%20--%20Engine_redacted-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.