# NTSB FTW83LA158: Piper PA-31T1, N879SW, Oklahoma City, OK, March 16, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 16, 1983, 16:50 local (22:50 UTC)
- Place: Oklahoma City, OK
- Coordinates: 35.550369, -97.559059 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.5504&lon=-97.5591&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 20839
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW83LA158
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20839/pdf
- Page: https://openairdocs.org/ntsb/FTW83LA158

## Sequence of events

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

- Complete gear collapsed, landing - roll
  - gear retraction - inadvertent, pilot in command (cause)
  - procedures/directives - not followed, pilot in command (contributing factor)
- On ground/water encounter with terrain/water, landing - roll

## Analysis

WITNESSES REPORTED THAT THE LANDING GEAR WAS LOWERED AT THE OUTER MARKER ON AN ILS APPROACH. THE PILOT STATED THAT HE EXTENDED FULL FLAPS AT ABOUT 400 FEET AGL JUST AS THEY BROKE OUT OF THE CLOUDS. ALMOST IMMEDIATELY AFTER LANDING THE PILOT RETRACTED THE FLAPS TO 0. THE FLAPS CAME UP AND THE NOSE OF THE AIRCRAFT FELL AS THE GEAR UP CYCLE BEGAN. THE MAIN GEAR THEN CAME UP AND THE AIRCRAFT SLID TO A STOP ON THE RUNWAY. WHEN THE AIRCRAFT WAS TRANSPORTED TO A HANGER, ALL LANDING GEAR WERE FOUND TO BE UP AND LOCKED. NUMEROUS CYCLE TESTS OF THE LANDING GEAR SYSTEM FAILED TO SHOW ANY MALFUNCTION WITHIN ANY COMPONENT OF THE SYSTEM.

## Aircraft

- Registration: [N879SW](https://openairdocs.org/deregistered/N879SW-2023-07-26), registration cancelled 2023-07-26, S/N 31T-7904056, built 1979 (OpenAirDocs)
- Reported make and model: PIPER PA-31T1
- Registry model: [Piper PA-31T1](https://openairdocs.org/model/piper-pa-31t1) (registry code 7103126) (OpenAirDocs)
- Registry engine: [Pratt & Whitney Canada PT6A-60A](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-60a) (registry code 52043, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 31T-7904056
- Airframe hours: 729
- Engines: P&W PT6A-11 500 horsepower turbo prop
- Damage: Substantial damage
- Flight: Business, Part 91
- Registered owner: Byron K. Lilly
- Airworthiness certificate: Standard, Normal
- Last inspection: Unknown, January 3, 1983, 29 hours before
- Departed: TUL, TULSA, OK
- Flight plan: IFR
- Airport: OKC, Will Rogers, runway 35R, 9,802 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, invalid medical for flight; seat: left; flight hours: 2,022 total, 728 in this make and model, 1,857 as pilot in command, 42 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 330° at 21 knots
- Visibility: 2 statute miles
- Lowest ceiling: 700 ft overcast
- Temperature: 84 °F, dew point 43 °F
- Altimeter: 29.00 inHg
- Observed at: OKC

## 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 19830316067259A](https://openairdocs.org/incident/19830316067259A), Mar 16, 1983: Piper PA31T1, Oklahoma City, OK, Substantial damage. Landing gear retracted on the landing roll. No defects found. Damage indicates inadvertent retraction by pilot.

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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