# NTSB DEN86LA239: Piper PA-23E-250, N900TS, Grand Forks, ND, August 26, 1986

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 26, 1986, 15:35 local (20:35 UTC)
- Place: Grand Forks, ND
- Coordinates: 47.910076, -97.070632 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.9101&lon=-97.0706&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 6 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 17041
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN86LA239
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17041/pdf
- Page: https://openairdocs.org/ntsb/DEN86LA239

## Sequence of events

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

- Airframe/component/system failure/malfunction, taxi - to takeoff
  - landing gear,normal retraction/extension assembly - bent (cause)
  - landing gear,normal retraction/extension assembly - disconnected (cause)
- On ground/water collision with object, taxi - to takeoff
  - airport facilities,runway/landing area condition - rough/uneven (contributing factor)
- Main gear collapsed, taxi - to takeoff

## Analysis

THE ACFT WAS EN ROUTE FROM FLIN FLON AIRPORT, MANITOBA, CD, TO MASON CITY, IA, AND HAD STOPPED AT GRAND FORKS, ND, FOR FUEL AND TO CLEAR CUSTOMS. DURING TAXI FOR TAKEOFF, THE ACFT STRUCK A 1-INCH CONCRETE LIP ON THE RAMP AND THE RIGHT MAIN LANDING GEAR COLLAPSED. POST ACCIDENT EXAMINATION REVEALED THE ACTUATOR ROD END WAS BENT AND ONE OF FOUR SPRINGS ON THE OVERCENTER CAM DEVICE WAS DETACHED FROM ITS PROPER ATTACH POINT AND WAS EXCESSIVELY STRETCHED. WITH THE ACFT ON JACKS THE SPRING WAS REATTACHED AND THE GEAR WAS EXTENDED, TRAPPING THE SPRING BETWEEN THE DOWNLOCK SWITCH AND THE DOWNLOCK OVERCENTER MECHANISM. WITH SOME WEIGHT APPLIED TO THE LANDING GEAR, A FIRM UPWARD PRESSURE WAS APPLIED TO THE OVERCENTER DEVICE AND THE RIGHT MAIN LANDING GEAR RETRACTED. FURTHER TESTS REVEALED THAT THE LANDING GEAR SELECTOR HANDLE DID NOT ALWAYS CATCH THE SAFETY LATCH WHEN PLACED IN THE NEUTRAL POSITION, AND THAT IT WAS POSSIBLE FOR THE SELECTOR TO GO FROM DOWN TO UP WITHOUT TRIGGERING THE LATCH.

## Aircraft

- Registration: [N900TS](https://openairdocs.org/aircraft/N900TS), registered now, S/N 27-7405429, built 1974 (OpenAirDocs)
- Reported make and model: PIPER PA-23E-250
- Registry model: [Piper PA-23-250](https://openairdocs.org/model/piper-pa-23-250) (registry code 7102308) (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: 27-7405429
- Engines: LYCOMING IO-540-C4B5 250 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: James Kenney, doing business as Vermillion Flying Service
- Airworthiness certificate: Standard, Normal
- Departed: GFK
- Destination: MCW, MASON CITY, IA
- Flight plan: IFR
- Airport: GFK, Grand Forks-Mark Andrews

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; commercial, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: valid medical--no waivers/lim.; seat: left; flight hours: 5,725 total, 33 in this make and model, 4,225 as pilot in command, 70 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 360° at 10 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 70 °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 19860826059359A](https://openairdocs.org/incident/19860826059359A), Aug 26, 1986: Piper PA23250, Grand Forks, ND, Substantial damage. Landing gear collapsed while taxiing. Overcenter altuator and spring damaged. Suspect inadvertent gear retraction.

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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