KatanaPilot
Well Known Member
I had an unusual experience on a flight back home earlier this week. Had four legs that day without issue.
Titan IO-360, Hartzell constant speed, dual Pmags, about 85 hours on the engine. It has been flawless until now. 6500 feet, about 50 degrees LOP, MP 23.6, 2400 RPM.
Started seeing erratic RPM indications, dropping as much as 150 RPM and you could feel the surging. I enrichened the mixture, brought RPMs up to 2500, still surging. Turned off one ignition - engine smooth as glass, EGT increased as expected. Assumed I had isolated a bad ignition system. Just to confirm, I turned that ignition back on, problem returned, also as expected. Turned off other ignition - expected really rough running, but engine ran smooth as glass.
Ignition systems have their own dedicated CB and lever lock switch - so it's not a keyswitch issue.
Wasn't far from home and there were no other suitable airports any closer, so continued home. Turned other ignition back on once overhead airport, engine ran fine, but power was pulled back for descent and landing.
Talked with Brad at Emag and he doesn't think it's an ignition issue.
Haven't had time to look for induction leaks, etc. but figured I'd reach out to the brain trust to see if anyone has had anything similar.
Titan IO-360, Hartzell constant speed, dual Pmags, about 85 hours on the engine. It has been flawless until now. 6500 feet, about 50 degrees LOP, MP 23.6, 2400 RPM.
Started seeing erratic RPM indications, dropping as much as 150 RPM and you could feel the surging. I enrichened the mixture, brought RPMs up to 2500, still surging. Turned off one ignition - engine smooth as glass, EGT increased as expected. Assumed I had isolated a bad ignition system. Just to confirm, I turned that ignition back on, problem returned, also as expected. Turned off other ignition - expected really rough running, but engine ran smooth as glass.
Ignition systems have their own dedicated CB and lever lock switch - so it's not a keyswitch issue.
Wasn't far from home and there were no other suitable airports any closer, so continued home. Turned other ignition back on once overhead airport, engine ran fine, but power was pulled back for descent and landing.
Talked with Brad at Emag and he doesn't think it's an ignition issue.
Haven't had time to look for induction leaks, etc. but figured I'd reach out to the brain trust to see if anyone has had anything similar.