# NTSB CEN10LA188: Beech 95, N20FP, Eden Prairie, MN, April 1, 2010

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: April 1, 2010, 14:40 local (19:40 UTC)
- Place: Eden Prairie, MN
- Coordinates: 44.827499, -93.45861 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.8275&lon=-93.4586&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Defining event: [Initial climb: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340)
- Highest injury: Serious injuries
- Injuries: 2 serious
- Status: Completed, report June 20, 2011
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA-Minneapolis FSDO
- NTSB case key (mKey): 75643
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN10LA188
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/75643/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=75643
- Page: https://openairdocs.org/ntsb/CEN10LA188

## Probable cause

The fatigue failure of an intake valve spring on the right engine, which resulted in a partial loss of engine power on takeoff.

## 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 95, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=1153402), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md)
- [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible; cases with it: [Beech 95, 1 case](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=1153402), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md)
- [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot; cases with it: [Beech 95, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1153402), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)

## Sequence of events

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

- [Initial climb: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Beech 95, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=1153402), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md)
- [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Beech 95, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=1153402), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Initial climb: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Beech 95, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=1153402), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md)
- [Initial climb: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Beech 95, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=1153402), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md)
- [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Beech 95, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=1153402), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

The pilot stated that he had no recollection of the events leading up to the accident. The passenger reported that the airplanes' engines seemed to come up to full power during takeoff. The airplane lifted off about halfway down the runway; however, it didn't climb very well. The stall warning sounded just as the airplane was off the end of the runway, and the pilot's efforts to continue flight were unsuccessful. The right wing dropped, and the airplane descended and impacted the ground. A witness reported that the airplane's nose was pitched up 10 to 15 degrees and the wings appeared to be level, as it was flying in ground effect about 10 feet agl. He noted that the engines seemed to be running without any obvious problems. A postaccident examination revealed a lack of compression on the right engine No. 4 cylinder. Further investigation determined that the intake valve spring on the cylinder had fractured. Metallurgical examination noted that the fracture surfaces exhibited features indicative of fatigue progression initiated by corrosion pitting. Corrosion pits and red rust deposits were observed on many areas of the spring. The fatigue initiation also coincided with longitudinal tooling marks consistent with the original forming of the spring. Maintenance records indicated the right engine had been overhauled nearly 2 years prior to the accident. The cylinders were replaced with new non-original equipment manufacturer (OEM) assemblies at that time. The replacement cylinder assemblies were furnished with the valves and valve springs installed. According to the pilot, the right engine had accumulated 18 hours since overhaul.

## Factual narrative

On April 1, 2010, about 1440 central daylight time, a Beech model 95, N20FP, impacted a flooded ravine about 2 miles south of Flying Cloud Airport (FCM), near Eden Prairie, Minnesota. The flight had departed from Runway 18 (2,691 feet by 75 feet, asphalt) at FCM. The pilot and passenger both sustained serious injuries. The airplane was registered to Fisher Air LLC, and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91, as a repositioning flight after avionics maintenance. Visual meteorological conditions prevailed for the flight, which was not operating on a flight plan. The flight was originating at the time of the accident. The pilot reported that the purpose of the flight was to reposition the airplane from FCM to New Richmond Regional Airport (RNH), New Richmond, Wisconsin, after avionics work has been completed. He stated that he had no recollection of the events leading up to the accident. The passenger stated that the engines seemed to come up to full power during takeoff. The airplane lifted off about halfway down the runway; however, it didn't climb very well. The stall warning sounded just off the end of the runway about 50 feet above ground level (agl). The pilot appeared to check the gear position and auxiliary fuel pump in an attempt to troubleshoot the problem. The pilot reduced the pitch attitude in an attempt to increase airspeed, but the airplane was unable to maintain altitude. The right wing dropped, and the airplane descended from an altitude of about 300 feet agl. It came to rest in a flooded area at the bottom of the hill off the end of the runway. A witness reported that the accident airplane's nose was pitched up about 10 to 15 degrees. The wings appeared to be level and it was flying in ground effect about 10 feet agl. He noted that the engines seemed to be running, and he did not recall hearing any sputtering or seeing any smoke. A hill dropped off past the end of the runway. The airplane came to rest upright about 30 yards out into a flooded area. The wings were facing north and the fuselage was canted about 30 degrees relative to the wings. The nose section was separated from the remainder of the fuselage and the windshield was broken out. There did appear to be fuel present at the accident site. Examination of the right engine revealed a lack of compression on the #4 cylinder. Further investigation determined that the #4 cylinder intake valve spring was fractured into 5 pieces. Metallurgical examination noted that some of the spring fracture surfaces had been damaged due to mechanical contact. However, the undamaged fracture surfaces exhibited features indicative of fatigue progression. Fatigue initiation was located at corrosion pits on the surface of the spring. Similar corrosion pits and red rust deposits were observed on many areas of the spring. The fatigue initiation also coincided with longitudinal tooling marks consistent with the original forming of the spring. The accidentairplane was a 1958 Beech model 95 (s/n TD-14). The airplane was powered by 2 Lycoming O-360-A1A engines, each capable of developing 180 horsepower. According to the maintenance logs, an annual inspection was completed on October 15, 2009, at 7,078.1 hours total airframe time. The left engine (s/n L515-36) was overhauled in July 1990. The right engine (s/n L2076-36) was overhauled in June 2008. The logs indicated that at the time of the annual inspection, the left and right engines had accumulated 1,837.0 hours and 2.1 hours since overhaul, respectively. On the NTSB accident report, the pilot noted that the left and right engines had accumulated 1,940 hours and 18 hours since overhaul, respectively. A flight log, entitled "Fisher Air – N20FP," was provided to the NTSB with the aircraft documentation. The log included flight times dated January 7, 2010, through April 1, 2010; the date of the accident. The flight time noted in that log totaled 14.1 hours.

## Aircraft

- Registration: [N20FP](https://openairdocs.org/deregistered/N20FP-2018-01-16), registration cancelled 2018-01-16, S/N TD-14, built 1957 (OpenAirDocs)
- Reported make and model: BEECH 95
- Registry model: [Beech 95](https://openairdocs.org/model/beech-95) (registry code 1153402) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: TD-14
- Airframe hours: 7078
- Engines: LYCOMING O&VO-360 SER 180 horsepower reciprocating; LYCOMING O&VO-360 SER 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Fischer Air LLC
- Registered owner: Fischer Air LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, October 5, 2009
- Departed: FCM, Minneapolis, MN
- Destination: RNH, New Richmond, MN
- Airport: FCM, Flying Cloud Airport, runway 18, 2,691 × 75 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; injuries: serious; airline transport; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review January 11, 2010; seat: left; flight hours: 11,320 total, 55 in this make and model, 11,220 as pilot in command, 60 in the last 90 days, 20 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 150° at 11 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 79 °F, dew point 52 °F
- Altimeter: 29.45 inHg
- Observed at: FCM, 2 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 20100401044999A](https://openairdocs.org/incident/20100401044999A), Apr 1, 2010: Beech 95, Eden Prairie, MN, Destroyed. 04-01-2010 Aircraft departed fcm on runway 18. Aircraft lost power immediately and descend in a flooded ravine area south of the airport. Aircraft impacted…

## Docket (9 files)

The files NTSB released with the investigation on May 9, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=75643. 10.1 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347028&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Passenger Statement (item 2, .PDF, 57 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347038&FileExtension=.PDF&FileName=Passenger%20Statement-Master.PDF
- Witness Statements (item 3, .PDF, 119 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347039&FileExtension=.PDF&FileName=Witness%20Statements-Master.PDF
- Mechanic Statement (item 4, .PDF, 61 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347057&FileExtension=.PDF&FileName=Mechanic%20Statement-Master.PDF
- Flight Log -- N20FP (item 5, .PDF, 187 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347056&FileExtension=.PDF&FileName=Flight%20Log%20--%20N20FP-Master.PDF
- Engine Examination Summary (item 6, .PDF, 48 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347055&FileExtension=.PDF&FileName=Engine%20Examination%20Summary-Master.PDF
- Maintenance Records -- Excerpts (item 7, .PDF, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347064&FileExtension=.PDF&FileName=Maintenance%20Records%20--%20Excerpts-Redacted.PDF
- Right Engine Overhaul Documentation (item 8, .PDF, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347059&FileExtension=.PDF&FileName=Right%20Engine%20Overhaul%20Documentation-Redacted.PDF
- Materials Laboratory 15 - Factual Report 11-037 (item 9, .PDF, 4.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40346620&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2011-037-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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