# NTSB SEA91LA163: Piper PA-25, N9792P, Musselshell, MT, July 13, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: July 13, 1991, 09:17 local (15:17 UTC)
- Place: Musselshell, MT
- Coordinates: 46.440608, -108.510498 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.4406&lon=-108.5105&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report March 24, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41475
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91LA163
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41475/pdf
- Page: https://openairdocs.org/ntsb/SEA91LA163

## Probable cause

THE PILOT'S INTENTIONAL STALL AT LOW ALTITUDE.

## Sequence of events

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

- Loss of control - in flight, maneuvering
  - stall - intentional, pilot in command (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - open field

## Analysis

AT THE END OF AN AERIAL APPLICATION FLIGHT, THE PILOT INTENTIONALLY STALLED THE AIRPLANE TO APPLY THE BRAKE TO THE WIND DRIVEN CHEMICAL PUMP. WHEN THE AIRPLANE STALLED, THE BRAKE WAS APPLIED AND AT THIS MOMENT, THE NOSE OF THE AIRPLANE DROPPED TO NEAR VERTICAL TO THE TERRAIN.  THE PILOT APPLIED FULL POWER.  HOWEVER, THE ENGINE DID NOT RESPOND. THE AIRPLANE THEN COLLIDED WITH THE TERRAIN IN A NOSE DOWN ATTITUDE.

## Aircraft

- Registration: [N9792P](https://openairdocs.org/deregistered/N9792P-1992-06-06), registration cancelled 1992-06-06, S/N 257556106 (OpenAirDocs)
- Reported make and model: PIPER PA-25
- Registry model: [Piper PA-25-260](https://openairdocs.org/model/piper-pa-25-260) (registry code 7102508) (OpenAirDocs)
- Category: Airplane
- Serial number: 25-7556106
- Engines: LYCOMING O-540 260 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Aerial application, Part 137
- Operator: Moore Quality Flying Service
- Registered owner: Moore Quality Flying Service
- Departed: MUSSELSHELL, MT

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; flight hours: 9,286 total, 800 in this make and model, 8,995 as pilot in command, 330 in the last 90 days, 150 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °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 19910713027379A](https://openairdocs.org/incident/19910713027379A), Jul 13, 1991: Piper PA25260, Musselshell, MT, Destroyed. Pulled up vertically to apply brake to chemical pump. Stalled and dived to vertical impact. Unable explain vertical

## Other investigations on N9792P (1)

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.

- [NTSB DEN82DA133](https://openairdocs.org/ntsb/DEN82DA133), Jul 11, 1982: Piper PA-25D-260 (N9792P), Edgeley, ND, substantial damage

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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