# NTSB ANC84FA137: Piper PA-18A, N1561P, Mckinley, AK, August 14, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Field investigation · Final report
- Date: August 14, 1984, 11:00 local (19:00 UTC)
- Place: Mckinley, AK
- Coordinates: 63.779911, -148.519622 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=63.7799&lon=-148.5196&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4223
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC84FA137
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4223/pdf
- Page: https://openairdocs.org/ntsb/ANC84FA137

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight collision with terrain/water, takeoff - initial climb
  - carburetor heat control - failure,partial (cause)
  - performance data - not understood, pilot in command (cause)
  - aborted takeoff - not performed, pilot in command (contributing factor)

## Analysis

THE ACFT CRASHED WHILE ATTEMPTNG A TAKEOFF FROM A GRAVEL BAR. THE PLT ESTIMATED THE USEABLE AREA FOR TAKEOFF AS 400 TO 500 FT. INVESTIGATION REVEALED THAT THE DENSITY ALTITUDE WAS AT LEAST 3400 FT MSL. A TEST ENG RUN AFTER THE ACFT WAS RECOVERED, DETERMINED THAT THE CARBURETOR HEAT 'BUTTERFLY' VALVE FUNCTIONED NORMALLY IN THE 'ON' POSITION BUT WHEN PLACED IN THE 'OFF' POSITION WOULD ONLY OPEN PARTIALLY. THIS PREVENTED THE ENG FROM DELIVERYING FULL STATIC POWER DURING THE TEST.

## Aircraft

- Registration: [N1561P](https://openairdocs.org/deregistered/N1561P-2014-09-05), registration cancelled 2014-09-05, S/N 18-3718, built 1954 (OpenAirDocs)
- Reported make and model: PIPER PA-18A
- Registry model: [Piper PA-18A-135](https://openairdocs.org/model/piper-pa-18a-135) (registry code 7101822) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 18-3718
- Airframe hours: 2740
- Engines: LYCOMING O-320-A2B 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Edward Donnall Thomas, Jr. Md
- Airworthiness certificate: Standard, Utility; Standard, Normal
- Last inspection: Annual, March 27, 1984, 70 hours before
- Departed: YANERT RIVER, AK
- Destination: 5MK, MCKINLEY PARK, AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; private; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: front; flight hours: 307 total, 206 in this make and model, 218 as pilot in command, 82 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 61 °F

## 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 19840814073749A](https://openairdocs.org/incident/19840814073749A), Aug 14, 1984: Piper PA18A135, Mckinley, AK, Substantial damage. Did not develop full power on takoff from short gravel bar. Carburetor heat valve malfunctioning.

## Other investigations on N1561P (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 ANC80DAG65](https://openairdocs.org/ntsb/ANC80DAG65), Jun 6, 1980: Piper PA-18A (N1561P), Beluga, AK, substantial damage

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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