# NTSB LAX85LA250: Rockwell S-2R, N8929Q, Colusa, CA, May 9, 1985

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 9, 1985, 13:00 local (20:00 UTC)
- Place: Colusa, CA
- Coordinates: 39.270229, -122.050659 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.2702&lon=-122.0507&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 24723
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX85LA250
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/24723/pdf
- Page: https://openairdocs.org/ntsb/LAX85LA250

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - engine assembly,valve,intake - failure,total (cause)
- Forced landing, descent
  - altitude - inadequate, pilot in command (contributing factor)
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - dirt bank/rising embankment

## Analysis

DURING AN AG FLIGHT, THE ENG BEGAN TO SEVERLY BACKFIRE & LOSE POWER. THE PLT ATTEMPTED TO MAKE A FORCED LDG ON THE NEARBY DUSTER AIRSTRIP BUT HAD INSUFFICIENT ALTITUDE TO BE PROPERLY ALIGNED WITH THE RWY. THE ACFT OVERAN THE EDGE OF THE END DISCLOSED THAT ITS #9 CYK EXHAUST VALVE BOSS HAD BROKEN CAUSING VALVE ACTION TO STOP. THE ENG HAD BEEN OPERATED FOR 30 HRS SINCE RECEIVING A MOH.

## Aircraft

- Registration: [N8929Q](https://openairdocs.org/aircraft/N8929Q), registered now, S/N 2354R, built 1977 (OpenAirDocs)
- Reported make and model: Rockwell S-2R
- Registry model: [Rockwell International S-2R](https://openairdocs.org/model/rockwell-international-s-2r) (registry code 7630202) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 2354R
- Engines: P&W R1340 SERIES 600 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Robert B. Caldwell
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Unknown, April 6, 1985
- Departed: COLUSA, CA
- Destination: COLUSA, CA
- Airport: Closby, runway 18, 2,600 ×  ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 8,000 total, 2,000 in this make and model, 8,000 as pilot in command, 150 in the last 90 days, 80 in the last 30 days, 8 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 5 knots, gusting 7
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 64 °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 19850509016319A](https://openairdocs.org/incident/19850509016319A), May 9, 1985: Ayres S2RR1340REST, Colusa, CA, Substantial damage. Power loss on takeoff caused by a broken exhaust valve boss. Landed across and ran off runway side,hit a dirt berm.

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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