On November 16, 1984, a Cessna 172C (registration N1554Y) operated by Robert A. Billbruck was involved in an aviation accident near Titusville, FL. Investigators recorded the probable cause as: The magneto key selector switch did not have the grounding lead connected to the right magneto position, allowing the magneto to be 'hot' when the selector was in the off position. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
After failing to start the engine, a pilot switched off the magnetos and master switch and exited the aircraft. Later, while moving the propeller with a hand toe bar, the aircraft started, taxied, and took off uncrewed, crashing into trees about a quarter mile from the airport.
Accident Overview
According to the pilot, after being unsuccessful in starting the aircraft's engine, he switched off the magnetos and master switch and exited the aircraft. Later, during the process of moving the propeller to a position to clear a hand toe bar, the aircraft started on its own. It then taxied across the airport and took off. The aircraft was found about a quarter mile from the airport, where it had crashed into trees.
Investigation Findings
Investigation revealed that the magneto key selector switch did not have the grounding lead connected to the right magneto position. This allowed the magneto to be 'hot' when the selector was in the off position. The absence of the grounding lead prevented the magneto from being properly grounded, enabling the engine to start despite the switch being turned off.
Probable cause
The magneto key selector switch did not have the grounding lead connected to the right magneto position, allowing the magneto to be 'hot' when the selector was in the off position.
Frequently asked questions
What happened in the 16 Nov 1984 Cessna 172C accident near Titusville, FL?
After failing to start the engine, a pilot switched off the magnetos and master switch and exited the aircraft. Later, while moving the propeller with a hand toe bar, the aircraft started, taxied, and took off uncrewed, crashing into trees about a quarter mile from the airport.
What aircraft was involved and where did it happen?
The accident on 16 Nov 1984 involved a Cessna 172C, registration N1554Y, operated by Robert A. Billbruck, at Titusville, FL.
What was the probable cause of the accident?
The magneto key selector switch did not have the grounding lead connected to the right magneto position, allowing the magneto to be 'hot' when the selector was in the off position.