# NTSB CEN09LA284: Cessna 421B, N60HG, Alpine, TX, May 8, 2009

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 8, 2009, 10:30 local (15:30 UTC)
- Place: Alpine, TX
- Coordinates: 30.429063, -103.32933 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=30.4291&lon=-103.3293&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report April 22, 2010
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: Cessna Aircraft Company, FAA FSDO, Continental Aircraft Engines
- NTSB case key (mKey): 73805
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN09LA284
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73805/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73805
- Page: https://openairdocs.org/ntsb/CEN09LA284

## Probable cause

The loss of engine power due to disengagement of the magneto idler gear support pin.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Malfunction (probable cause); cases with it: [Cessna 421B, 2 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=2076014), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)
- [Maintenance/inspections](https://openairdocs.org/ntsb-findings/01010500): Aircraft › Aircraft handling/service · Not specified; cases with it: [Cessna 421B, 3 cases](https://openairdocs.org/ntsb-findings/01010500/cases.md?model=2076014), [All aircraft, 103 cases](https://openairdocs.org/ntsb-findings/01010500/cases.md)
- [Ignition system: magneto/distributor](https://openairdocs.org/ntsb-findings/01057414): Aircraft › Aircraft power plant · Malfunction (probable cause); cases with it: [Cessna 421B, 1 case](https://openairdocs.org/ntsb-findings/01057414/cases.md?model=2076014), [All aircraft, 101 cases](https://openairdocs.org/ntsb-findings/01057414/cases.md)

## Sequence of events

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

- [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Cessna 421B, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2076014), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Initial climb: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 421B, 3 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2076014), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Initial climb: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 421B, 11 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2076014), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

Shortly after departure, when the airplane was about 400 feet in the air, the right engine stopped producing power. The pilot conducted a forced landing in a nearby field. An on-site inspection revealed that the airplane fuel tanks contained plenty of fuel. A post accident examination of the engines was conducted. An engine monitor was downloaded; a sudden decrease in cylinder head (CHT) and exhaust gas (EGT) temperature readings were observed for the right engine. A visual inspection of the engine revealed that the idler gear support pin, located on the rear of the engine, had backed out. The idler pin's retaining hardware (two nuts and lock-washers) were missing. The idler pin's movement allowed the idler gear to drop and become disconnected from the magnetos drive gear, resulting in a loss of engine ignition. Additionally, due to the mis-located idler gear, the accessory drive gears on the cam and crankshafts were either ground down or broken. Disassembly of the engine, found numerous metal pieces in the engine's oil sump.

## Factual narrative

On May 8, 2009, approximately 1030 central daylight time, a twin-engine Cessna 421B, N60HG, was substantially damaged during a forced landing following the loss of engine power shortly after takeoff, near Alpine, Texas. The commercial pilot, sole occupant, received minor injuries during the forced landing. The airplane was registered and operated by O'Hara Flying Service, Amarillo, Texas. Visual meteorological conditions prevailed and a flight plan was not filed for the Title 14 Code of Federal Regulations Part (CFR) 91 positioning flight destined for the Rick Husband Amarillo International Airport (AMA), Amarillo, Texas. The pilot reported that, shortly after takeoff when the airplane was about 400 feet in the air, the right engine stopped producing power. As the pilot reached up to feather the right engine, the left engine "surged and sounded like it was going to quit." The pilot moved the engine controls forward, and looked for a place for a forced landing. The pilot added that he felt he did not have full power on the left engine. The airplane impacted several small bushes during the off-airfield landing. A Federal Aviation Administration (FAA) inspector who responded to the site reported that the airplane had plenty of fuel and that it appeared consistent with 100LL aviation grade fuel. An examination of the aircraft wreckage was conducted by the NTSB Investigator-in-Charge (IIC), along with technical representatives from the airframe and engine manufacturers, at Air Salvage of Dallas (ASOD) on 28 May, 2009. A JPI engine monitor was downloaded; a sudden decrease in cylinder head (CHT) and exhaust gas (EGT) temperature readings were observed for the right engine. A visual inspection of the engine revealed that the idler gear support pin, located on the rear of the motor, had backed out. The idler pin's retaining hardware (two nuts and lock-washers) were missing. The idler pin's movement allowed the idler gear to drop, and become disconnected from the magneto drive gears, resulting in a loss of engine ignition. The idler gear teeth were severely worn. Additionally, the accessory drive gears on the cam and crankshafts were either ground down or broken. Disassembly of the engine, found numerous metal pieces in the engine's oil sump. Examination of the left engine and engine monitor readings, revealed no apparent abnormalities. The engine was rotated to obtain thumb compression and drive train continuity. Each cylinder was borescoped; the sparkplugs were light gray in color and appeared "normal." The magnetos were removed and rotated by hand, producing spark at each terminal. The engine's oil filer was cut open, inspected, and was found to be clear of any metal.

## Aircraft

- Registration: [N60HG](https://openairdocs.org/deregistered/N60HG-2011-06-01), registration cancelled 2011-06-01, S/N 421B0534, built 1973 (OpenAirDocs)
- Reported make and model: CESSNA 421B
- Registry model: [Cessna 421B](https://openairdocs.org/model/cessna-421b) (registry code 2076014) (OpenAirDocs)
- Registry engine: [Continental GTSIO-520-C](https://openairdocs.org/engine/continental-gtsio-520-c) (registry code 17035, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 421B0534
- Airframe hours: 7543
- Engines: CONT MOTOR GTSIO-520-C 340 horsepower reciprocating; CONT MOTOR GTSIO-520-C 340 horsepower reciprocating
- Damage: Substantial damage
- Flight: Positioning, Part 91
- Operator: O'Hara Flying Service II Lp
- Registered owner: O'Hara Flying Service II Lp
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, April 1, 2009
- Departed: Alpine, TX
- Destination: AMA, Amarillo, TX
- Airport: E38, Alpine-Casparis Municipal Apt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review February 9, 2009; seat: left; flight hours: 8,818 total, 95 in this make and model, 8,060 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: 230° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 88 °F, dew point 36 °F
- Altimeter: 29.94 inHg
- Observed at: KE38

## 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 20090508053949A](https://openairdocs.org/incident/20090508053949A), May 8, 2009: Cessna 421B, Alpine, TX, Substantial damage. On may 8, 2009, aircraft N60HG, a Cessna 421B, departed E38 (Alpine) airport at approximately 1030 CDT. The aircraft climbed to approximately 300 feet AGL. The…

## Docket (5 files)

The files NTSB released with the investigation on February 3, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73805. 2.0 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40324160&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Weather Reports and Records (item 2, .PDF, 48 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40324161&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF
- Release of Aircraft Wreckage, NTSB Form 6120.15 (item 3, .PDF, 461 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40324183&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF
- Statement of Party Representatives to NTSB Investigation (item 4, .PDF, 138 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40324467&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF
- Photo: Idler Gear Pin (item 5, .PDF, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40324180&FileExtension=.PDF&FileName=Photo%3A%20Idler%20Gear%20Pin-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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