# NTSB DEN82DA111: Weatherly 201C, N9228W, Near Rapelje, MT, June 21, 1982

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: June 21, 1982, 06:30 local (12:30 UTC)
- Place: Near Rapelje, MT
- Coordinates: 45.950233, -109.270271 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.9502&lon=-109.2703&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 21, 1983
- Report: Approved by Office Director
- NTSB case key (mKey): 71920
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN82DA111
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/71920/pdf
- Page: https://openairdocs.org/ntsb/DEN82DA111

## Sequence of events

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

- Loss of control - on ground/water, landing - roll
  - hydraulic system,seal - brittle fracture (cause)
  - fluid,hydraulic - leak (cause)
  - landing gear,normal brake system - inoperative (cause)
  - directional control - not possible, pilot in command
  - ground loop/swerve - uncontrolled, pilot in command
- On ground/water collision with object, landing - roll
  - object - utility pole (contributing factor)

## Analysis

WHILE LANDING ON A COUNTY ROAD, THE PILOT LOST DIRECTIONAL CONTROL AND THE AIRCRAFT VEERED TO THE LEFT AND STRUCK A POLE. AN INVESTIGATION REVEALED THAT AN 0-RING, PN 101-00500, ON THE PARKING BRAKE VALVE IN THE RIGHT MASTER CYLINDER HAD FAILED AND HYDRAULIC FLUID WAS LOST. THE BROKEN O-RING WAS NO LONGER SOFT AND PLIABLE, BUT WAS HARD AND NON-FLEXIBLE. ACCORDING TO RECORDS, THE CLEVELAND BRAKES HAD BEEN MANUFACTURED IN JUNE 1977. THE ONLY RECORDED MAINTENANCE ON THE BRAKES (SINCE BEING MANUFACTURED) WAS ON 5/15/82 WHEN THE BRAKE DISC LININGS WERE REPLACED.

## Aircraft

- Registration: [N9228W](https://openairdocs.org/deregistered/N9228W-2000-11-02), registration cancelled 2000-11-02, S/N 1036 (OpenAirDocs)
- Reported make and model: WEATHERLY 201C
- Registry model: [Weatherly 201C](https://openairdocs.org/model/weatherly-201c) (registry code 9630410) (OpenAirDocs)
- Category: Airplane
- Serial number: 1036
- Airframe hours: 1159
- Engines: P&W R-985 450 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 137
- Operator: Aguet
- Registered owner: Hoppys Agri Aero Service, Inc.
- Departed: 12, NEAR RAPELJE, MT
- Destination: 12, NEAR RAPELJE, MT
- Airport: 12, County Road #306, runway 36, 5,280 × 0 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 23; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; flight hours: 1,058 total, 281 in this make and model, 975 as pilot in command, 70 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 90° at 3 knots
- Visibility: 20 statute miles
- Temperature: 131 °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 19820621028379A](https://openairdocs.org/incident/19820621028379A), Jun 21, 1982: Wthrly 201C, Rapelje, MT, Substantial damage. Right brake failed on landing roll causing aircraft to hit pole. Failed p/n was 101-00500.

## Other investigations on N9228W (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 CHI00LA178](https://openairdocs.org/ntsb/CHI00LA178), Jun 30, 2000: Weatherly 201C (N9228W), Tolna, ND, destroyed, 1 fatal. Probable cause: the wing spar fatigue and wing separation while maneuvering. A factor was that the fatigue was not detected by the mechanic during the last annual inspection.

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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