# NTSB DEN90LA123: Piper PA-18-150, N4720A, Douglas, WY, June 4, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 4, 1990, 11:30 local (17:30 UTC)
- Place: Douglas, WY
- Coordinates: 42.749637, -105.389801 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.7496&lon=-105.3898&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 15, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 17940
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN90LA123
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17940/pdf
- Page: https://openairdocs.org/ntsb/DEN90LA123

## Probable cause

THE ACCIDENT TO BE IMPROPER INSTALLATION OF AILERON CONTROL SYSTEM BY MAINTENANCE PERSONNEL, AND FAILURE TO PERFORM AN AIRCRAFT PREFLIGHT BY THE PILOT IN COMMAND.

## Sequence of events

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

- Loss of control - in flight, takeoff - initial climb
  - flt control syst,aileron control - incorrect (cause)
  - maintenance,installation - improper, other maintenance personnel (cause)
  - aircraft preflight - not performed, pilot in command (cause)
- In flight collision with terrain/water, descent - emergency

## Analysis

THE AIRPLANE HAD BEEN COMPLETELY RECOVERED WITH NEW FABRIC AND THE PILOT WAS GOING TO FERRY IT BACK TO HIS RANCH. WITNESSES SAID THE PILOT DID NOT PERFORM A PREFLIGHT CHECK. THE AIRPLANE TOOK OFF, CLIMBED TO AN ALTITUDE OF 15 TO 30 FEET, THEN BANKED STEEPLY TO THE RIGHT AND CRASHED. EXAMINATION OF THE FLIGHT CONTROL SYSTEM DISCLOSED THE AILERON CONTROL CABLES HAD BEEN INADVERTENTLY CROSSED DURING REASSEMBLY.

## Aircraft

- Registration: [N4720A](https://openairdocs.org/aircraft/N4720A), registered now, S/N 18-4941, built 1956 (OpenAirDocs)
- Reported make and model: PIPER PA-18-150
- Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 18-4941
- Airframe hours: 3078
- Engines: LYCOMING O-320-A2A 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Norman Ranch Company
- Registered owner: Norman Ranch Co.
- Airworthiness certificate: Standard, Normal; Standard, Utility
- Last inspection: Annual, June 1, 1990
- Departed: DGW
- Destination: NONE, ROZET, WY
- Airport: DGW, Converse County, runway 28, 6,750 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 67; private; airplane ratings: single-engine land; medical: class 3, expired; seat: front; flight hours: 3,823 total, 30 in the last 90 days, 9 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 32 knots, gusting 37
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 82 °F, dew point 30 °F
- Altimeter: 29.00 inHg
- Observed at: CPR, 48 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 19900604018399A](https://openairdocs.org/incident/19900604018399A), Jun 4, 1990: Piper PA18150, Douglas, WY, Substantial damage. Just out of shop new fabric. No preflite. Took off in gusty wind. Banked. Crashed. Aileron controls were crossed.

## Other investigations on N4720A (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 DEN67D0041](https://openairdocs.org/ntsb/DEN67D0041), Jul 13, 1966: Piper PA-18 (N4720A), Roset, WY, 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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