July 8, 2014
By Dave Hirschman
Editor's Note: An earlier version of this story contained outdated information on when the system can predict impending exhaust valve failures.
In a development that could improve the safety and reliability of piston aircraft engines, Savvy Analysis founder Mike Busch has developed an automated warning system for impending exhaust valve failures.
The company’s new computer program scans data from electronic engine monitors and spots the signs of valve failures before they happen. Exhaust valve failures are one of the leading causes for potentially catastrophic power losses in piston aircraft engines.
“For close to 10 years, I’ve been talking about the fact that a large percentage of impending exhaust valve failures can be detected through analysis of EGT data in piston aircraft that have a recording engine monitor installed,” said Busch, who also writes about maintenance topics for AOPA's Opinion Leaders blog. “The symptom of an incipient failure is a slow, rhythmic EGT oscillation with a frequency of the general order of one cycle per minute and an amplitude of 30-to-100 degrees Fahrenheit.”
Savvy “Pro” customers pay $129 a year to have their engine data analyzed will get it reviewed by the new Failing Exhaust Valve Analytics (FEVA) program. In cases where FEVA indicates trouble, Savvy customers will have their engines undergo a minimally invasive borescope inspection to gather more details.
A borescope inspection involves removing a spark plug and inserting a miniature camera into the cylinder to examine exhaust valves for unusual wear. Borescope inspections are becoming increasingly common as new technology has reduced the price of borescopes and improved the quality of the images they produce.
Savvy Analysis has collected an unprecedented amount of engine data through computerized examination of more than 600,000 general aviation flights, and its pool of information is growing rapidly. The company is planning other products based on the safety trends it identifies through ongoing data collection and rigorous analysis. More information is available online.
AOPA Pilot Senior Editor Dave Hirschman joined AOPA in 2008. He has an airline transport pilot certificate and instrument and multiengine flight instructor certificates. Dave flies vintage, historical, and Experimental airplanes and specializes in tailwheel and aerobatic instruction.
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General Aviation Statistics,
AOPA is working to make sure that members are not taxed for tax-exempt aircraft parts and services in Florida.
Exhaust system design is critical to the ultimate power output of an aircraft engine. Regardless of improvements to induction air flow, compression, cylinder porting, or combustion timing, a poorly designed exhaust system will always limit the power that your engine can deliver.
The FAA allows aircraft owners to perform many preventive maintenance tasks provided they do not involve complex assembly operations.
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