# NTSB CEN12LA580: Cessna 140, N140XX, Spearfish, SD, August 25, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 25, 2012, 11:00 local (17:00 UTC) - Place: Spearfish, SD - Coordinates: 44.818889, -103.988609 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.8189&lon=-103.9886&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 12, 2013 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA FSDO Rapid City - NTSB case key (mKey): 84833 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN12LA580 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84833/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84833 - Page: https://openairdocs.org/ntsb/CEN12LA580 ## Probable cause The partial loss of engine power due to debris lodged beneath the throttle body of the carburetor venturi. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Not specified (probable cause); cases with it: [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [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: [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: [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis After an uneventful cross-country flight, the solo student pilot was setting up to enter the downwind leg of the traffic pattern at his destination airport. When he applied carburetor heat, the engine rpm dropped below 1000. Unable to continue to the planned runway, the student pilot elected to land the airplane in an adjacent field. During the landing roll, the airplane struck a barbed wire fence and nosed over, coming to rest inverted. Postaccident examination of the engine revealed debris lodged in the throttle body beneath the carburetor venturi. The debris appeared to be remnants of aluminum tape or foil. Additionally, what appeared to be a small piece of exhaust insulation or asbestos wrap was found within the carburetor heat box. No other anomalies with the engine or airframe were discovered that could have contributed to the partial loss of engine power. It is unknown how long the foreign object debris was present below the carburetor venturi; however, the airplane had operated for about 3 flight hours since its most recent annual inspection, which was conducted 3 months before the accident flight. The presence of debris lodged beneath the carburetor venturi is consistent with the student pilot's statement that he experienced a loss of power and engine rpm when carburetor heat was applied. ## Factual narrative On August 25, 2012, approximately 1100 mountain daylight time, a Cessna 140, N140XX, registered to the student pilot, sustained substantial damage during a forced landing after a partial loss of engine power in the vicinity of the Black Hills Airport - Clyde Ice Field (SPF), Spearfish, South Dakota. The student pilot, who was on a cross country solo flight, was not injured. Visual meteorological conditions prevailed in the vicinity and a flight plan was not filed. The flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. The final portion of the multi-airport flight originated at 1000 from the Philip Airport (PHP), Philip, South Dakota. The pilot reported that he was nearing the end of his uneventful cross country student solo flight and set up for a downwind at SPF. As he applied carburetor heat, the engine RPM dropped below 1000. Unable to continue to the planned runway, the pilot elected to land the airplane in an adjacent field. During the landing roll, the airplane struck a barb wired fence and nosed over inverted, resulting in substantial damage to the vertical stabilizer and rudder. The pilot exited the airplane uninjured. Post accident examination of the engine revealed foreign object debris (FOD) lodged in the throttle body beneath the carburetor venturi. The debris appeared to be remnants of aluminum tape/foil. Also found was what appeared to be a small piece of exhaust insulation/asbestos wrap within the carburetor heat box. No other anomalies with the engine or airframe were discovered. It is unknown how long the foreign object debris was present below the carburetor venturi. The airplane and engine had operated normally for about 3 flight hours after its last annual inspection, dated May 3, 2012. The tachometer time at the time of the annual inspection was 1,473 hours. The tachometer time at the time of the accident was 1,476 hours. ## Aircraft - Registration: N140XX (not matched to a registry record) - Reported make and model: CESSNA 140 - Category: Airplane - Serial number: 8847 - Airframe hours: 1476 - Engines: CONT MOTOR C85 SERIES 85 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Bowen Bruce C - Registered owner: Bowen Bruce C - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 3, 2012, 1,473 hours before - Departed: PHP, Philip, SD - Destination: SPF, Spearfish, SD - Airport: SPF, Black Hills Airport-Clyde Ice ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; injuries: none; student; medical: class 3, with waivers/limitations; seat: left; flight hours: 70 total, 70 in this make and model, 20 as pilot in command, 4 in the last 90 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 350° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 37 °F - Altimeter: 30.09 inHg - Observed at: SPF, 1 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 20120825019259A](https://openairdocs.org/incident/20120825019259A), Aug 25, 2012: Cessna 140, Spearfish, SD, Substantial damage. On Saturday August 25th at about 11:00 MDT a Cessna 140 was involved in an accident near kspf airport. After a cross country solo, the pilot went through the… ## Docket (7 files) The files NTSB released with the investigation on July 31, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84833. 396 KB in all. - Pilot Statement (item 1, .PDF, 23 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396157&FileExtension=.PDF&FileName=Pilot%20Statement-Redacted.PDF - Witness Statement (item 2, .PDF, 20 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396158&FileExtension=.PDF&FileName=Witness%20Statement-Redacted.PDF - Record of Telephone Conversation with FSDO Inspector (item 3, .PDF, 40 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396159&FileExtension=.PDF&FileName=Record%20of%20Telephone%20Conversation%20with%20FSDO%20Inspector-Master.PDF - Photo 1 Debris Lodged Beneath Carburetor Venturi (item 4, .PDF, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396160&FileExtension=.PDF&FileName=Photo%201%20Debris%20Lodged%20Beneath%20Carburetor%20Venturi-Master.PDF - Photo 2 Debris Lodged Beneath Carburetor Venturi (item 5, .PDF, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396161&FileExtension=.PDF&FileName=Photo%202%20Debris%20Lodged%20Beneath%20Carburetor%20Venturi-Master.PDF - Photo 3 Damage to Front of Airplane (item 6, .PDF, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396162&FileExtension=.PDF&FileName=Photo%203%20Damage%20to%20Front%20of%20Airplane-Master.PDF - Photo 4 Damage to Vertical Stabilizer (item 7, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396163&FileExtension=.PDF&FileName=Photo%204%20Damage%20to%20Vertical%20Stabilizer-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.