# NTSB SEA94LA116: Aero Commander S2R, N5646X, Dayton, WA, May 7, 1994

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 7, 1994, 07:15 local (14:15 UTC)
- Place: Dayton, WA
- Coordinates: 46.30978, -117.899841 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.3098&lon=-117.8998&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report December 7, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 41922
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA94LA116
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41922/pdf
- Page: https://openairdocs.org/ntsb/SEA94LA116

## Probable cause

TOTAL FAILURE OF THE CONNECTING ROD.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, maneuvering - aerial application
  - engine assembly,connecting rod - failure,total (cause)
- Forced landing, descent - emergency
- On ground/water encounter with terrain/water, landing - roll

## Analysis

DURING AN AERIAL APPLICATION FLIGHT, THE PILOT REPORTED THAT THE ENGINE BEGAN TO RUN ROUGH AND THE CHIP DETECTOR LIGHT ILLUMINATED. WHILE EN ROUTE BACK TO THE AIRSTRIP THE ENGINE LOST POWER AND THE PILOT MADE A FORCED LANDING IN AN OPEN FIELD. DURING THE LANDING ROLL, THE AIRPLANE COLLIDED WITH ROUGH TERRAIN. INSPECTION OF THE ENGINE REVEALED THAT THE NUMBER FIVE CONNECTING ROD BROKE.

## Factual narrative

On May 7, 1994, at 0715 Pacific daylight time an Aero Commander S2R, N5646X, experienced a loss of engine power during an aerial application flight near Dayton, Washington.  Visual meteorological conditions prevailed at the time and no flight plan was filed.  The airplane was substantially damaged and the commercial pilot was not injured.

The pilot reported that during a spray operation, the engine began to run rough and the chip detector light illuminated.  While en route back to the airstrip, the engine began to smoke and a backfire was heard.  The engine lost power and the airplane was unable to make it to the airstrip.  The pilot initiated a forced landing to an open field, short of the airstrip, where the airplane collided with the terrain during the landing roll.

During the inspection of the engine, it was found that the number five connecting rod broke.

## Aircraft

- Registration: [N5646X](https://openairdocs.org/aircraft/N5646X), registered now, S/N 1846R, built 1973 (OpenAirDocs)
- Reported make and model: AERO COMMANDER S2R
- Registry model: [Aero Commander S2R](https://openairdocs.org/model/aero-commander-s2r) (registry code 0143022) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 1846R
- Engines: WRIGHT R-1820-97 900 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Ag Air Inc.
- Registered owner: Ag Air Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, March 18, 1994

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 5,400 total, 300 in this make and model, 5,400 as pilot in command, 150 in the last 90 days, 100 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 12 knots, gusting 15
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 64 °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 19940507018749A](https://openairdocs.org/incident/19940507018749A), May 7, 1994: Ayres S2RR1820, Dayton, WA, Substantial damage. Engine ran rough. Chip light on. Tried return base. Collided with terrain. Found broken connecting rod.

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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