# NTSB CHI83IA105: Gates Learjet LR-25, N4PN, Wilkes Barre, PA, February 9, 1983

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: February 9, 1983, 08:55 local (13:55 UTC)
- Place: Wilkes Barre, PA
- Location: 41.2466° N, 75.8757° W: Placed by OpenAirDocs: center of Wilkes-Barre, PA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=41.2466&lon=-75.8757&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 12044
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI83IA105
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/12044/pdf
- Page: https://openairdocs.org/ntsb/CHI83IA105

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise
  - autopilot/flight director,disengage unit - too cold (cause)
  - weather condition (contributing factor)

## Analysis

ACFT AUTOPILOT/AUTOTRIM SYSTEM FAILED TO DISENGAGE DUE TO A MALFUNCTION OF THE ENGAGE SWITCH WHICH OCCURRED ONLY IN COLD ENVIRONMENT.

## Aircraft

- Registration: N4PN (not matched to a registry record)
- Reported make and model: GATES LEARJET LR-25
- Category: Airplane
- Serial number: 003
- Airframe hours: 7680
- Engines: GE CJ 610-6 turbo jet
- Damage: No damage
- Flight: Executive/Corporate, Part 91
- Registered owner: Precisin National Corporation
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, February 3, 1983, 9 hours before
- Departed: AVP, WILKES BARRE, PA
- Destination: MVN, MOUNT VERNON, IL
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 61; airline transport, flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 15,100 total, 2,202 in this make and model, 14,500 as pilot in command, 92 in the last 90 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 320° at 9 knots
- Lowest ceiling: 25,000 ft overcast
- Temperature: 19 °F, dew point 7 °F
- Observed at: AVP, 20 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).

- [Incident 19830209074039I](https://openairdocs.org/incident/19830209074039I), Feb 9, 1983: Lear 25, Wilkes Barre, PA. Autopilot failed to disengage for a manual trim climb. Excessive nose down trim. Temperature restricted switch.

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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