# NTSB WPR12LA306: Cessna 172N, N5204K, Rockford, ID, July 16, 2012 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 16, 2012, 09:50 local (15:50 UTC) - Place: Rockford, ID - Coordinates: 43.189445, -112.531669 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.1894&lon=-112.5317&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 22, 2015 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 84339 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12LA306 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84339/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84339 - Page: https://openairdocs.org/ntsb/WPR12LA306 ## Probable cause A partial loss of engine power during cruise flight due to the failure of the No. 3 cylinder exhaust valve for reasons that could not be determined due to the damage to the valve head and the missing valve stem. Contributing to the accident was the flight instructor’s improper approach to the runway, which resulted in an aborted landing and subsequent off-airport landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Cessna 172N, 13 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2072434), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Performance/control parameters: descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 172N, 16 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md?model=2072434), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md) - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Cessna 172N, 29 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=2072434), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Cessna 172N, 11 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=2072434), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); 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) - [Landing-flare/touchdown: 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 flight instructor reported that, while the airplane was in level cruise flight, the engine began to vibrate, and the rpm dropped to about 1,900. The airplane could not maintain altitude, so the instructor took control of the airplane and chose to divert to a nearby airport. During the approach, the altitude and airspeed were too high to safely land on the runway, so the instructor aborted the landing. He subsequently made a forced landing to an open field. During the landing, the airplane nosed over and came to rest inverted, which resulted in substantial damage to the wings and tail section. A postaccident examination of the engine revealed that the Nos. 2 and 3 cylinders had no compression. A large amount of metal dust and debris were found in the No. 2 cylinder's intake and exhaust ports. The No. 3 cylinder was removed, and the exhaust valve head was found embedded in the cylinder head. The piston head was severely damaged, and the valve stem was missing and had likely exited the engine out of the exhaust. The reason for the failure of the No. 3 cylinder exhaust valve could not be determined due to the damage to the exhaust valve head and the missing valve stem. Although the debris in the No.2 cylinder's ports would have prevented the valve from sealing properly and resulted in reduced compression, it would not have caused the partial loss of engine power as the No. 3 cylinder's failure would have. ## Factual narrative On July 16, 2012, at 0950 mountain daylight time, a Cessna 172N, N5204K, experienced a partial loss of engine power during level cruise flight. The pilot subsequently initiated a forced landing in an open field, and came to rest inverted near Rockford, Idaho. The certified flight instructor and student pilot were not injured. The airplane sustained substantial damage to the wings and the tail section. The airplane was registered to Teton Leasing, LLC, and operated by the pilot under the provisions of 14 Code of Federal Regulations (CFR) Part 91 for the instructional cross-country flight. Visual meteorological conditions prevailed, and a visual flight rules (VFR) flight plan was filed. The flight originated from Idaho Falls Regional Airport (IDA), Idaho Falls, Idaho, at 0835. The flight instructor reported he had intended to conduct a cross-country flight from IDA to Arco-Butte County Airport (AOC), Arco, Idaho, into McCarley Field Airport (U02), Blackfoot, Idaho, and back to IDA. The flight from IDA to AOC was uneventful. About 12 miles northwest of U02, the engine began to vibrate, and the engine revolutions dropped to approximately 1,900 rpm. Carburetor heat was applied, the mixture was set to rich, and the fuel selector was in the BOTH position. The airplane could not maintain altitude, and the flight instructor took control, and decided to divert for a landing at Rockford Municipal Airport (2U4), Rockford. Upon arrival at 2U4, the flight instructor determined the winds were calm, and elected to land on runway 16. During the landing sequence, the altitude and airspeed were too high to safely land on the runway. He subsequently aborted the landing, and initiated a forced landing to a wheat field. During the touchdown, the airplane collided with the wheat; the airplane's nose pitched down, and came to rest inverted. A postaccident examination by a Federal Aviation Administration (FAA) inspector was conducted on the engine. The visual inspection of the engine revealed no catastrophic failures; however, during the compression check, the numbers two and three cylinders had no compression. A closer inspection of the number three cylinder revealed damage to the piston head, and the exhaust valve was not present. The intake tubes for the numbers two and three cylinders, as well as, the exhaust system for the engine were removed. With the exhaust section removed, the FAA inspector was able to see the head of the missing valve embedded into the cylinder head. The valve stem was missing and not located. Inspection of the number two cylinder revealed a large amount of metal dust and debris in the intake and exhaust ports. ## Aircraft - Registration: [N5204K](https://openairdocs.org/deregistered/N5204K-2014-09-03), registration cancelled 2014-09-03, S/N 17274009, built 1980 (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: 17274009 - Airframe hours: 12691.9 - Engines: LYCOMING O-320-H2AD 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Teton Leasing LLC - Registered owner: Teton Leasing LLC - Airworthiness certificate: Standard, Normal; Standard, Utility - Last inspection: Annual, June 8, 2012 - Departed: IDA, Idaho Falls, ID - Destination: 2U4, Rockford, ID - Flight plan: VFR - Airport: 2U4, Rockford Municipal Airport, runway 16, 2,800 × 50 ft, asphalt - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 63; injuries: none; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review March 23, 2011; seat: right; flight hours: 1,939 total, 213 in this make and model, 1,817 as pilot in command, 84 in the last 90 days, 31 in the last 30 days, 2 in the last 24 hours - Student pilot; age 29; injuries: none; student; medical: class 3, without waivers/limitations; seat: left; flight hours: 25 total, 10 in this make and model, 4 as pilot in command, 11 in the last 90 days, 7 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 50° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 10,000 ft broken - Temperature: 73 °F, dew point 55 °F - Altimeter: 30.01 inHg - Observed at: PIH, 17 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 20120716014229A](https://openairdocs.org/incident/20120716014229A), Jul 16, 2012: Cessna 172N, Rockford, ID, Substantial damage. Aircraft lost power 45 minutes into flight resulting in forced landing 1.5 miles se of Rockford, ID in a field. Upon landing a/c flipped over. Instructor… ## Other investigations on N5204K (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 SEA05CA043](https://openairdocs.org/ntsb/SEA05CA043), Feb 3, 2005: Cessna 172N (N5204K), Idaho Falls, ID, substantial damage. Probable cause: The student pilot's failure to maintain directional control and the instructor's inadequate supervision of the flight. A contributing factor was the deep snow beside the runway. ## Docket (8 files) The files NTSB released with the investigation on May 18, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84339. 11.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - Pilot (item 1, .PDF, 613 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426483&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20Pilot-Redacted.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 - Director of Maintenance (item 2, .PDF, 568 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426484&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20-%20Director%20of%20Maintenance-Redacted.PDF - FAA Inspector Statement (item 3, .PDF, 190 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426485&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement-Redacted.PDF - Bingham County Sheriff's Report (item 4, .PDF, 716 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426486&FileExtension=.PDF&FileName=Bingham%20County%20Sheriff%27s%20Report-Redacted.PDF - Photo 1 - No. 3 Cylinder (Photo Courtesy of FAA) (item 5, .PDF, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426487&FileExtension=.PDF&FileName=Photo%201%20-%20No.%203%20Cylinder%20(Photo%20Courtesy%20of%20FAA)-Master.PDF - Photo 2 - No. 3 Cylinder (Photo Courtesy of FAA) (item 6, .PDF, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426488&FileExtension=.PDF&FileName=Photo%202%20-%20No.%203%20Cylinder%20(Photo%20Courtesy%20of%20FAA)-Master.PDF - Photo 3 - No. 3 Cylinder Exhaust Valve (Photo Courtesy of FAA) (item 7, .PDF, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426489&FileExtension=.PDF&FileName=Photo%203%20-%20No.%203%20Cylinder%20Exhaust%20Valve%20(Photo%20Courtesy%20of%20FAA)%20-Master.PDF - Photo 4 - No. 3 Cylinder Piston Head (Photo Courtesy of FAA) (item 8, .PDF, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40426490&FileExtension=.PDF&FileName=Photo%204%20-%20No.%203%20Cylinder%20Piston%20Head%20(Photo%20Courtesy%20of%20FAA)-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.