# NTSB CEN10LA032: Cessna 210, N7464E, Walsh, CO, October 27, 2009

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: October 27, 2009, 14:00 local (21:00 UTC)
- Place: Walsh, CO
- Coordinates: 37.347778, -102.257774
- Nearby events: https://openairdocs.org/map.md?lat=37.3478&lon=-102.2578&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report May 28, 2010
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA Flight Standards District Office
- NTSB case key (mKey): 74965
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN10LA032
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74965/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74965
- Page: https://openairdocs.org/ntsb/CEN10LA032

## Probable cause

A partial loss of engine power due to failure of the No. 2 cylinder as a result of the failure of the repair facility to properly torque the lower four nuts on the cylinder.

## 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 · Incorrect service/maintenance (probable cause); cases with it: [Cessna 210, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=2073402), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Terrain: wet/muddy terrain](https://openairdocs.org/ntsb-findings/03021035): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna 210, 1 case](https://openairdocs.org/ntsb-findings/03021035/cases.md?model=2073402), [All aircraft, 110 cases](https://openairdocs.org/ntsb-findings/03021035/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Cessna 210, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2073402), [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 210, 9 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2073402), [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) (defining event); cases with it: [Cessna 210, 3 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2073402), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The airplane was in level cruise flight at 6,500 feet mean sea level when the pilot "detected a slight smoke smell." Oil pressure and oil temperature readings were normal, but he noticed the EGT (exhaust gas temperature) on one of the cylinders had dropped, followed shortly thereafter by the EGT decay of another cylinder. The pilot was forced to make an emergency landing in an open field. Recent rains had softened the ground and when the nosewheel touched down, the airplane nosed over. An FAA airworthiness inspector who examined the engine said that the cylinder hold-down studs on the lower side of the number 2 cylinder had threads, but one stud had snapped off. Further examination of the engine revealed that the lower four nuts on the number two cylinder were not properly torqued, which allowed the lower side of the cylinder to move while the upper part remained fixed. A crack developed on the right side of the cylinder and propagated along the bottom lip to the left side of the cylinder, eventually reaching the point of failure. When the annual and 100-hour inspections were done on August 21, 2009, all 6 cylinders had been removed “due to low compression” and replaced with overhauled cylinders, new pistons and rings, and new gaskets and seals. Airframe total time was 3,797.79 hours, and the time since major engine overhaul was 1,239.82 hours. The tachometer read 2960.72. At the accident site, the tachometer read 3059.41 hours.

## Factual narrative

On October 27, 1009, approximately 1700 mountain daylight time, a Cessna 210, N5464E registered to and piloted by an airline transport-certificated pilot, was substantially damaged when it nosed over and impacted terrain following a loss of engine power near Walsh, Colorado. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91, and a VFR (visual flight rules) flight plan had been filed and activated. The pilot, the sole occupant on board, sustained minor injuries. The cross-country flight originated at Ulysses, Kansas, approximately 1730 central daylight time, and was en route to Farmington, New Mexico. According to the pilot, he was in level cruise flight at 6,500 feet msl (above mean sea level) when he "detected a slight smoke smell." Oil pressure and oil temperature readings were normal, but he noticed the EGT (exhaust gas temperature) on one of the cylinders had dropped, followed shortly thereafter by the EGT decay of another cylinder. He diverted towards Springfield, Colorado, Municipal Airport, but was forced to make an emergency landing in an open field near Walsh, Colorado. Recent rains had softened the ground and when the nose wheel touched down, the airplane nosed over. An FAA airworthiness inspector went to the scene and examined the engine. He noted that the cylinder hold-down studs on the lower side of the number 2 cylinder had threads, but one stud had snapped off. The wreckage was verbally released to the owner’s attorney on January 20, 2010, and the engine was transported to the facilities of Air Salvage of Dallas where, on March 2, 2010, it was disassembled and examined. NTSB and FAA attended. NTSB’s air safety investigator said that it appeared that the lower four nuts on the number two cylinder were not properly torque, which allowed the lower side of the cylinder to move while the upper part remained fixed. A crack developed on the right side of the cylinder and propagated along the bottom lip to the left side of the cylinder. Eventually, it reached the point of failure. Examination of the maintenance records revealed that when the annual and 100-hour inspections were done on August 21, 2009, all 6 cylinders were removed “due to low compression,” and replaced with overhauled cylinders, new pistons and rings, and new gaskets sand seals. Airframe total time was 3,797.79 hours, and the time since engine major overhaul was 1,239.82 hours. The tachometer read 2960.72. At the accident site, the tachometer read 3059.41 hours.

## Aircraft

- Registration: [N7464E](https://openairdocs.org/deregistered/N7464E-2013-07-08), registration cancelled 2013-07-08, S/N 57164, built 1960 (OpenAirDocs)
- Reported make and model: CESSNA 210
- Registry model: [Cessna 210](https://openairdocs.org/model/cessna-210) (registry code 2073402) (OpenAirDocs)
- Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 57164
- Airframe hours: 3798
- Engines: Continental IO-470-E 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: William L. Gold
- Registered owner: William L. Gold
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 21, 2009
- Departed: ULS, Ulysses, KS
- Destination: FMN, Farmington, NM
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 52; injuries: minor; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review June 2, 2009; seat: left; flight hours: 8,500 total, 800 in this make and model, 7,500 as pilot in command, 70 in the last 90 days, 35 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 48 °F, dew point 39 °F
- Altimeter: 29.35 inHg
- Observed at: LAA, 63 nm away

## Docket (8 files)

The files NTSB released with the investigation on March 25, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74965. 1.1 MB in all.

- NTSB Form 6120.1-2, Pilot-Operator Aircraft Accident Report (item 1, .PDF, 455 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40322098&FileExtension=.PDF&FileName=NTSB%20Form%206120.1-2,%20Pilot-Operator%20Aircraft%20Accident%20Report-Redacted.PDF
- Excerpts from Aircraft Maintenance Records (item 2, .PDF, 131 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40327422&FileExtension=.PDF&FileName=Excerpts%20from%20Aircraft%20Maintenance%20Records-Redacted.PDF
- Weather Reports and Records (item 3, .PDF, 24 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40321547&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF
- Photo 1. N7464E shortly after the forced landing. (item 4, .PDF, 32 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40326968&FileExtension=.PDF&FileName=Photo%201.%20N7464E%20shortly%20after%20the%20forced%20landing.-Master.PDF
- Photo 2. The engine after cowling removal. Note separated number 2 cylinder. (item 5, .PDF, 83 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40326969&FileExtension=.PDF&FileName=Photo%202.%20The%20engine%20after%20cowling%20removal.%20Note%20separated%20number%202%20cylinder.-Master.PDF
- Photo 3. Close-up view of number 2 cylinder. (item 6, .PDF, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40326971&FileExtension=.PDF&FileName=Photo%203.%20Close-up%20view%20of%20number%202%20cylinder.-Master.PDF
- Photo 4. Crack initiation on number 2 cylinder. Note shiney area on cylinder lip. (item 7, .PDF, 160 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40326972&FileExtension=.PDF&FileName=Photo%204.%20Crack%20initiation%20on%20number%202%20cylinder.%20Note%20shiney%20area%20on%20cylinder%20lip.-Master.PDF
- Photo 5. Crack propagated along bottom lip and cylinder failed. Note gray matte area. (item 8, .PDF, 170 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40326973&FileExtension=.PDF&FileName=Photo%205.%20Crack%20propagated%20along%20bottom%20lip%20and%20cylinder%20failed.%20Note%20gray%20matte%20area.-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.

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