# NTSB SEA92LA089: Pilatus B-4 PC 11A, N279AS, Wenatchee, WA, May 3, 1992

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Limited investigation · Final report
- Date: May 3, 1992, 14:20 local (21:20 UTC)
- Place: Wenatchee, WA
- Coordinates: 47.3703, -120.349166 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.3703&lon=-120.3492&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report August 13, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41667
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA92LA089
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41667/pdf
- Page: https://openairdocs.org/ntsb/SEA92LA089

## Probable cause

FAILURE BY THE PILOT TO MAINTAIN AIRSPEED, RESULTING IN AIRCRAFT STALL.

## Sequence of events

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

- Loss of control - in flight, maneuvering
  - airspeed(vs) - not maintained, pilot in command (cause)
  - stall - inadvertent, pilot in command
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT WAS MANEUVERING AT A LOW ALTITUDE ABOVE A RIDGE WHEN THE AIRCRAFT NOSED UP, ROLLED INVERTED, DESCENDED IN A NOSE DOWN ATTITUDE AND IMPACTED THE GROUND.

## Aircraft

- Registration: [N279AS](https://openairdocs.org/deregistered/N279AS-2012-09-21), registration cancelled 2012-09-21, S/N 261, built 1977 (OpenAirDocs)
- Reported make and model: PILATUS B-4 PC 11A
- Registry model: [Pilatus B4-PC11AF](https://openairdocs.org/model/pilatus-b4-pc11af) (registry code 7090103) (OpenAirDocs)
- Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs)
- Category: Glider
- Serial number: 261
- Airframe hours: 1090
- Engines: unknown
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Butler, John
- Registered owner: Butler, John
- Airworthiness certificate: Standard, Aerobatic
- Last inspection: Annual, May 3, 1991, 28 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 68; private; seat: center; toxicology performed; flight hours: 52 total, 40 in this make and model, 29 as pilot in command, 4 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 8 knots
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 79 °F, dew point 37 °F
- Altimeter: 30.00 inHg
- Observed at: EAT, 4 nm away

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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