# NTSB ANC21LA060: Piper PA-18-135, N99640, Skwentna, AK, July 16, 2021

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: July 16, 2021, 12:20 local (20:20 UTC)
- Place: Skwentna, AK · NE Corner of Chelatna Lake
- Coordinates: 62.533065, -151.50171 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=62.5331&lon=-151.5017&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: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Alaska Regional Office
- Parties: FAA
- NTSB case key (mKey): 103516
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC21LA060
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103516/pdf
- Page: https://openairdocs.org/ntsb/ANC21LA060

## Probable cause

The pilot’s use of excessive braking which resulted in a nose-over.

## Findings

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

- [Landing gear system: brake](https://openairdocs.org/ntsb-findings/01023242): Aircraft › Aircraft systems · Incorrect use/operation (probable cause); cases with it: [Piper PA-18-135, 2 cases](https://openairdocs.org/ntsb-findings/01023242/cases.md?model=7101820), [All aircraft, 297 cases](https://openairdocs.org/ntsb-findings/01023242/cases.md)
- [Performance/control parameters: surface speed/braking](https://openairdocs.org/ntsb-findings/01062045): Aircraft › Aircraft oper/perf/capability · Incorrect use/operation (probable cause); cases with it: [Piper PA-18-135, 2 cases](https://openairdocs.org/ntsb-findings/01062045/cases.md?model=7101820), [All aircraft, 238 cases](https://openairdocs.org/ntsb-findings/01062045/cases.md)
- [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Piper PA-18-135, 3 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=7101820), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md)

## Sequence of events

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

- [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) (defining event); cases with it: [Piper PA-18-135, 10 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=7101820), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

The pilot stated that he was landing on an unimproved runway with calm winds. After landing, he applied brakes, but felt he needed more. When he increased brake pressure, the tail of the airplane rose, the prop struck the ground and the airplane flipped over, resulting in substantial damage to the rudder, vertical stabilizer and right lift strut. The pilot reported that there were no mechanical malfunctions or failures that would have precluded normal operation.

## Aircraft

- Registration: [N99640](https://openairdocs.org/deregistered/N99640-2023-06-17), registration cancelled 2023-06-17, S/N 54-2642 (OpenAirDocs)
- Reported make and model: PIPER PA-18-135
- Registry model: [Piper PA-18-135](https://openairdocs.org/model/piper-pa-18-135) (registry code 7101820) (OpenAirDocs)
- Category: Airplane
- Serial number: 54-2642
- Year built: 1954
- Airframe hours: 3542
- Engines: Lycoming O320-A2B 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: B-407 LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, September 8, 2020, 55 hours before
- Departed: 4AK6, Wasilla, AK
- Destination: Same as departure
- Airport: PVT, Private
- Equipment: ADS-B, Electronic flight bag or handheld device

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 71; injuries: none; airline transport, commercial, flight instructor; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: basicmed; last flight review June 19, 2021; seat: rear; restraint: 4-point; flight hours: 27,085 total, 84 in this make and model, 19,132 as pilot in command, 30 in the last 90 days, 10 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 310° at 3 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 70 °F, dew point 52 °F
- Altimeter: 30.03 inHg
- Observed at: PATK, 41 nm away
- METAR: PATK 161953Z 31003KT 10SM CLR 21/11 A3003 RMK AO2 SLP169 T02110111

## 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 20210716010769A](https://openairdocs.org/incident/20210716010769A), Jul 16, 2021: Piper PA-18-135, Chelatna Lake, AK, Substantial damage. Pilot departed wolf lake airport(4AK6) with one passenger, enroute to an approximately 750' long private Airstrip at Chelatna Lake. Calm winds and clear skies.…

## Other investigations on N99640 (1)

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.

- [NTSB ANC22LA020](https://openairdocs.org/ntsb/ANC22LA020), Feb 27, 2022: Piper PA-18-135 (N99640), Wasilla, AK, substantial damage. Probable cause: A partial loss of engine power for undetermined reasons.

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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