# NTSB SEA92LA025: Swearingen SA-227-AC, N26932, Missoula, MT, December 2, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 1, 1991, 18:55 local (Dec 2, 1991, 01:55 UTC)
- Place: Missoula, MT
- Coordinates: 46.850475, -113.989852 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.8505&lon=-113.9899&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 18 uninjured
- Status: Completed, report April 23, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41614
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA92LA025
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41614/pdf
- Page: https://openairdocs.org/ntsb/SEA92LA025

## Probable cause

THE PILOT'S INABILITY TO MAINTAIN DIRECTIONAL CONTROL DURING TAKEOFF.  FACTORS INCLUDE A DRAGGING BRAKE.

## Sequence of events

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

- Loss of control - on ground/water, landing
  - airport facilities,runway/landing area condition - snow covered
  - landing gear,normal brake system - other (contributing factor)
  - directional control - not maintained, pilot in command (cause)
- On ground/water encounter with terrain/water, takeoff - aborted
  - terrain condition - snowbank

## Analysis

THE PILOT WAS UNABLE TO MAINTAIN DIRECTIONAL CONTROL AS THE AIRCRAFT DRIFTED OFF THE LEFT SIDE OF THE DEPARTURE RUNWAY, WHICH HAD AN ACCUMULATION OF SNOW.  THE INABILITY TO MAINTAIN DIRECTIONAL CONTROL AT HIGH SPEED WAS CONSISTENT WITH AA DRAGGING BRAKE ON THE LEFT SIDE OF THE AIRCRAFT.

## Aircraft

- Registration: N26932 (not matched to a registry record)
- Reported make and model: SWEARINGEN SA-227-AC
- Category: Airplane
- Serial number: AC660
- Airframe hours: 11645
- Engines: GARRETT TPE 331-11U 1050 horsepower turbo prop
- Damage: Substantial damage
- Flight: Part 135
- Operator: Horizon Air
- Registered owner: Mcdonnell Douglas Finance Corp
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, November 22, 1991, 74 hours before
- Destination: GEG, SPOKANE, WA
- Flight plan: IFR
- Airport: MSO, Johnson-Bell, runway 29, 9,499 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 31; commercial, airline transport; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 6,800 total, 2,000 in this make and model, 6,000 as pilot in command, 174 in the last 90 days, 72 in the last 30 days, 8 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Night/dark
- Wind: 220° at 5 knots
- Visibility: 1 statute miles
- Lowest ceiling: 800 ft
- Temperature: 27 °F, dew point 25 °F
- Altimeter: 29.00 inHg

## 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 19911201060279A](https://openairdocs.org/incident/19911201060279A), Dec 1, 1991: Swrngn SA227AC, Missoula, MT, Substantial damage. Veered off center on takeoff. Aborted. Slid off runway striking lights. Light crosswind. Braking fair to poor on snow

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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