# NTSB CEN13LA229: Beech N35, N9414Y, Warren, AR, April 15, 2013

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: April 15, 2013, 09:45 local (14:45 UTC)
- Place: Warren, AR
- Coordinates: 33.560554, -92.085281 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.5606&lon=-92.0853&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report June 1, 2015
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA Flight Standards, Continental Motors Group
- NTSB case key (mKey): 86661
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13LA229
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86661/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86661
- Page: https://openairdocs.org/ntsb/CEN13LA229

## Probable cause

The fatigue failure of the engine crankshaft due to oversized crankcase saddle bores, which resulted from maintenance personnel improperly resizing the saddle bores during engine maintenance.

## 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: [Beech N35, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=1151528), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Beech N35, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=1151528), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Beech N35, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=1151528), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Maintenance](https://openairdocs.org/ntsb-findings/02062000): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Beech N35, 2 cases](https://openairdocs.org/ntsb-findings/02062000/cases.md?model=1151528), [All aircraft, 143 cases](https://openairdocs.org/ntsb-findings/02062000/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 (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Beech N35, 6 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1151528), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Beech N35, 4 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1151528), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)

## Analysis

The pilot reported that the engine lost power during the initial climb. He then established a glide in an attempt to return to the airport; however, due to "strong" wind, the airplane landed "abruptly short of the runway." A postaccident engine examination revealed that the crankshaft had fractured due to fatigue through the No. 3 cheek immediately aft of the No. 2 main bearing journal. Portions of the saddle bore diameter at the nose of the crankshaft were oversized. The crankcase No. 2 main bearing saddle exhibited longitudinal deformation adjacent to the bore with fretting and galling on the saddle landings. The No. 1 main bearing shells were deformed; the No. 2 main bearing shells were worn, deformed, and partially split. The remaining bearings exhibited helical lines that matched the machining lines on the crankcase main bearing saddles. The tin coating had been worn away except around the oil transfer holes. The appearance of the main bearing shells was consistent with the bearings shifting during operation due to insufficient crush, which was likely caused by the oversized main saddle bore diameters. Maintenance records indicated that the engine was disassembled about 15 months before the accident due to a propeller strike. At that time, maintenance personnel cut the crankcase mating surfaces and resized the saddle bores. The engine had accumulated about 16.5 hours since the engine was reinstalled. It is likely that maintenance personnel improperly resized the saddle bores during the engine maintenance.

## Factual narrative

On April 15, 2013, about 0945 central daylight time, a Beech model N35 airplane, N9414Y, was substantially damaged during a forced landing following a loss of engine power after takeoff from the Warren Municipal Airport (3M9), Warren, Arkansas. The pilot and passenger sustained minor injuries. The aircraft was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight. An instrument flight rules flight plan had been filed, but not yet activated. The flight was originating at the time of the accident. The intended destination was the Mena Intermountain Municipal Airport (MEZ), Mena, Arkansas.The pilot reported that he had departed from runway 21 (3,829 feet by 75 feet, asphalt) at 3M9 and climbed to 700 feet mean sea level (msl). As he started a right turn to the west, about 1,000 feet msl, the engine lost power. He established a glide in an attempted to return to the airport. However, due to "strong" winds, the airplane contacted the ground "abruptly short of the runway." A postaccident engine teardown and subsequent metallurgical examination were conducted. The crankcase was cracked starting at the number 1 cylinder head mounting stud and continuing to the top of the case. The crankcase number 2 main bearing saddle exhibited longitudinal deformation adjacent to the bore, with fretting and galling on the saddle landings. The other saddles exhibited curvilinear marks on the split plane landings and helical marks on the saddle bores, consistent with machining marks. The crankcase was re-assembled and the saddle bore diameter at the nose of the crankshaft was measured. The bore diameter was within limits in the area centered 90-degrees from the split plane. However, the bore diameter was oversized in the area centered about 20-degrees from the split plane. The bore diameter measured 2.5660 inch; the bore diameter limits were 2.5625 inch to 2.5635 inch. The crankshaft had fractured through the number 3 cheek, immediately aft of the number 2 main bearing journal. The fracture surfaces exhibited curvilinear crack propagation marks consistent with fatigue. The main bearing surface exhibited circumferential abrasion marks. The main bearing journal diameters measured within the limits for a reground crankshaft, with the exception of the number 2 journal. The number 1 main bearing shells were deformed; the number 2 main bearing shells were worn, deformed and partially split. The remaining bearings exhibited helical lines that matched the machining lines on the crankcase main bearing saddles. The tin coating on the backside of the bearings had been worn away except around the oil transfer holes. Dimensional inspection of the number 3, 4 and 5 main bearing shells were within limits. Engine maintenance records indicated that the engine was overhauled in January 2001, at 1,526.5 hours total time. According to the records, an annualinspection was completed on December 10, 2009, at 1,696.7 hours total time, with 170.4 hours since overhaul. The next entry indicated that the engine was removed from the previous airframe "for prop strike on or about 8 – 11." This entry noted the total time as 1,526.5 hours, which was the same as at overhaul about 9 years earlier. However, the time since overhaul was the same as at the December 10th annual inspection. An entry dated January 10, 2012, noted that the engine had been disassembled due to a propeller strike. At that time, the crankshaft was magnetic particle inspected with negative findings. The crankcase mating surfaces were cut and the bores were resized to the manufacturer's limits. It was subsequently installed on the accident airplane on March 5, 2013. An annual inspection was completed at that time. The recording tachometer time was noted as 216.8 hours. There were no subsequent entries in the either the airframe or engine maintenance logbooks. The recording tachometer indicated 233.31 hours after recovery of the airplane. Based on the tachometer time noted at the annual inspection, about 16.5 hours had accumulated since the inspection.

## Aircraft

- Registration: [N9414Y](https://openairdocs.org/deregistered/N9414Y-2018-03-08), registration cancelled 2018-03-08, S/N D-6592, built 1960 (OpenAirDocs)
- Reported make and model: BEECH N35
- Registry model: [Beech N35](https://openairdocs.org/model/beech-n35) (registry code 1151528) (OpenAirDocs)
- Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: D-6592
- Airframe hours: 6266
- Engines: CONT MOTOR IO-520-BA(6) 285 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: William M. Morris
- Registered owner: William M. Morris
- Airworthiness certificate: Standard, Utility; Standard, Normal
- Last inspection: Annual, March 5, 2013
- Departed: 3M9, Warren, AR
- Destination: MEZ, Mena, AR
- Flight plan: IFR
- Airport: 3M9, Warren Municipal, runway 21, 3,829 × 75 ft, asphalt
- Equipment: Stall warning system

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; injuries: minor; flight instructor, flight engineer, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review February 24, 2013; seat: left; flight hours: 7,832 total, 800 in this make and model, 7,436 as pilot in command, 100 in the last 90 days, 25 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 170° at 6 knots
- Visibility: 10 statute miles
- Lowest ceiling: 1,300 ft overcast
- Temperature: 66 °F, dew point 61 °F
- Altimeter: 29.87 inHg
- Observed at: LLQ, 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 20130415006099A](https://openairdocs.org/incident/20130415006099A), Apr 15, 2013: Beech N35, Warren, AR, Destroyed. On 04/15/2013 N9414Y was taking off from Warren Airport (3M9) aircraft was being operated by the owner/pilot an ATP rated pilot with a valid 1st class medical.…

## Docket (5 files)

The files NTSB released with the investigation on April 27, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86661. 8.2 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 553 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425554&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- NTSB Materials Laboratory Factual Report (item 2, .PDF, 11 photos, 3.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425555&FileExtension=.PDF&FileName=NTSB%20Materials%20Laboratory%20Factual%20Report-Master.PDF
- Airframe Maintenance Logbook (item 3, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425556&FileExtension=.PDF&FileName=Airframe%20Maintenance%20Logbook-Redacted.PDF
- Engine Maintenance Logbook (item 4, .PDF, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425557&FileExtension=.PDF&FileName=Engine%20Maintenance%20Logbook-Redacted.PDF
- Statement of Party Representatives to NTSB Investigation (item 5, .PDF, 80 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40425558&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.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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