# NTSB ANC10CA002: Piper PA-31-350, N27231, Nondalton, AK, October 10, 2009

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: October 10, 2009, 11:05 local (19:05 UTC)
- Place: Nondalton, AK
- Coordinates: 59.979999, -154.839172 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=59.9800&lon=-154.8392&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern final: Loss of control in flight](https://openairdocs.org/ntsb-events/240)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report April 19, 2010
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 74894
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC10CA002
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74894/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74894
- Page: https://openairdocs.org/ntsb/ANC10CA002

## Probable cause

The pilot's decision to attempt a landing in weather conducive to strong downdrafts, resulting in a loss of control.

## Findings

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

- [Aircraft capability: climb capability](https://openairdocs.org/ntsb-findings/01061010): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Piper PA-31-350, 1 case](https://openairdocs.org/ntsb-findings/01061010/cases.md?model=7103110), [All aircraft, 183 cases](https://openairdocs.org/ntsb-findings/01061010/cases.md)
- [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Decision related to condition (probable cause); cases with it: [Piper PA-31-350, 1 case](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=7103110), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md)
- [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Piper PA-31-350, 9 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=7103110), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md)

## Sequence of events

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

- [Approach-VFR pattern final: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Piper PA-31-350, 4 cases](https://openairdocs.org/ntsb-events/400/sequence.md?model=7103110), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md)
- [Approach-VFR pattern final: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Piper PA-31-350, 7 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7103110), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md)
- [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Piper PA-31-350, 3 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=7103110), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md)
- [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Piper PA-31-350, 8 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=7103110), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md)

## Analysis

The solo airline transport pilot reported that he was landing on a gravel-covered airstrip, at the conclusion of a Title 14, Code of Federal Regulations Part 91 positioning flight. He reported that while on final approach, the airplane "encountered a sinker" and it began to descend below his anticipated approach path. He added full engine power to stop the descent, but the airplane continued to descend, and it landed hard on the right side of the runway. During touchdown, the airplane’s landing gear collapsed, and it continued to slide for about 150 yards, resulting in substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical problems with the airplane. A weather reporting station 14 miles south of the accident site reported wind from 110 degrees at 24 knots, gusting to 35 knots 12 minutes before the accident.

## Factual narrative

The solo airline transport pilot reported he was landing a twin-engine airplane on a gravel-covered airstrip, at the conclusion of a Title 14, Code of Federal Regulations Part 91 positioning flight. He reported that while on final approach, the airplane "encountered a sinker" and it began to descend below his anticipated approach path. He added full engine power to stop the descent, but the airplane continued to descend, and it landed hard on the right side of the runway. During touchdown, the airplane’s landing gear collapsed, and it continued to slide for about 150 yards, resulting in substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical problems with the airplane. A weather reporting station 14 miles south of the accident site reported wind from 110 degrees at 24 knots, gusting to 35 knots 12 minutes before the accident.

## Aircraft

- Registration: [N27231](https://openairdocs.org/deregistered/N27231-2018-01-03), registration cancelled 2018-01-03, S/N 31-7752106, built 1977 (OpenAirDocs)
- Reported make and model: PIPER PA-31-350
- Registry model: [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350) (registry code 7103110) (OpenAirDocs)
- Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 31-7752106
- Airframe hours: 11810
- Engines: LYCOMING TIO-540 SER 310 horsepower reciprocating; LYCOMING TI0-540 SER 310 horsepower reciprocating
- Damage: Substantial damage
- Flight: Positioning, Part 91
- Operator: Lake Clark Air Inc
- Registered owner: Lake Clark Air Inc
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, September 23, 2009, 48 hours before
- Departed: ILI, Iliamna, AK
- Destination: 5NN, Nondalton, AK
- Airport: 5NN, Nondalton Airport, runway 20, 2,800 × 75 ft, gravel

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 55; injuries: none; commercial, airline transport; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review September 13, 2009; seat: left; flight hours: 27,930 total, 8,925 in this make and model, 27,719 as pilot in command, 332 in the last 90 days, 70 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 110° at 24 knots, gusting 35
- Visibility: 10 statute miles
- Lowest ceiling: 3,100 ft overcast
- Temperature: 52 °F, dew point 43 °F
- Altimeter: 29.70 inHg
- Observed at: ILI, 14 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 20091010050299A](https://openairdocs.org/incident/20091010050299A), Oct 10, 2009: Piper PA-31-350, Nondalton, AK, Substantial damage. The aircraft developed a high sink rate while on approach to the Nondalton airport. Pilot added full power which was not sufficient to effect a sucessful…

## Docket (1 files)

The files NTSB released with the investigation on November 3, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74894. 574 KB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 574 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40320553&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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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