Pilot Debrief

AVIAT AIRCRAFT INC A 1B near Geneva, FL — 2016-11-02

Final reportERA17LA037
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Date
2016-11-02
Location
Geneva, FL, USA
Aircraft
AVIAT AIRCRAFT INC A 1B
Registration
N54HY
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

A partial loss of engine power due to debris in the No. 1 cylinder that damaged the spark plugs.

NTSB narrative

The commercial pilot reported that, about 10 minutes into the banner tow flight, the engine began to run roughly. He adjusted the throttle, propeller lever, mixture, and carburetor heat; however, the engine started to backfire and continued to lose power. The pilot performed a precautionary landing on a race track; during the landing roll, the airplane struck a fence before coming to rest. The engine continued to operate during the landing roll until the airplane struck the fence. Postaccident examination of the engine revealed that the No. 1 cylinder top and bottom spark plug electrodes exhibited mechanical damage; no mechanical damage was noted on the other spark plugs. The No. 1 piston looked like it was "sandblasted" compared to the other cylinders. Further disassembly of the engine was performed; no debris was noted in the carburetor box, carburetor, and No. 1 cylinder. Maintenance was performed on the engine 2 days before the accident to troubleshoot "hard starting, low static RPM, and a rough engine." The maintenance entry indicated that both No. 1 cylinder spark plugs were damaged and that new spark plugs were installed. A comparison of the photographs of the spark plugs removed from the No. 1 cylinder during maintenance and the spark plugs removed from the No. 1 cylinder after the accident showed similar mechanical damage. Although no debris was found during the postaccident examination, it is likely that both sets of No. 1 spark plugs were damaged by debris in the No. 1 cylinder; the source of the debris could not be located.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have returned to X50 after engine began to run rough.

NTSB coding

Evidence available

  • Photos
  • 8 docket documents
View NTSB final reportView NTSB docket

Docket documents8

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