P&E/A&P: Early warning of valve trouble

Engine monitor data can predict failures

August 7, 2014

In a development that could improve the safety and reliability of piston aircraft engines, Savvy Analysis founder Mike Busch has created 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.

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Close examination of exhaust valves using a borescope can show a failing valve characterized by a green hue,

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or a healthy valve characterized by a circular burn pattern.

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Computer analysis of engine data (left) shows yellow EGT spikes that warn of an impending exhaust valve failure.

“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,” Busch said. “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 Analysis Pro customers pay $129 a year for singles to have their engine data analyzed 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. The AOPA Air Safety Institute recently published a poster developed in conjunction with Adrian Eichhorn which shows the progression of valve wear in high-definition photos (www.aopa.org/Pilot-Resources/Air-Safety-Institute/Valve-Safety).

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. AOPA

Email dave.hirschman@aopa.org

Web: www.savvyanalysis.com

Dave Hirschman

Dave Hirschman | AOPA Pilot Senior Editor, AOPA

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.