EAA Sport Aviation - September 2010

If your airplane isn’t equipped with a digital engine monitor with CHT alarm capability, do yourself a favor and install one.

because that’s the most likely time for foreign material to get into the fuel system. I’ve had two serious clogged-nozzle episodes in my airplane over the past 23 years, and both occurred shortly after an annual inspection.

SOLUTIONS

Regardless of the cause, the solution is not rocket science. There are two simple rules that will almost always prevent these sorts of destructive events from occurring.

First, check your fuel flow gauge early on every takeoff roll. If the fuel flow is not at redline or very close to it, abort the takeoff and sort things out on the ground. The exception is takeoffs at high-density altitudes in normally aspirated airplanes, and detonation is quite unlikely under those conditions.

Second, set your engine monitor CHT alarm to 400°F or less (I have mine set to 390°F). When the alarm goes off, immediately do whatever it takes to bring the CHT back down below 400°F. Verify that the mixture is full rich, and turn on the boost pump if it isn’t already on. Open the cowl flaps if you have them. If CHT climbs above 420°F, throttle back aggressively. Don’t be shy about doing these things immediately, because you may have only a minute or two to act before your engine craters.

If your airplane isn’t equipped with a digital engine monitor with CHT alarm capability, do yourself a favor and install one. Trust me, it’ll pay for itself quickly.

When you get on the ground, put the airplane in the shop and have the spark plugs removed and inspected for damage, the cylinders borescoped, and the magneto timing checked. If takeoff fuel flow was short of redline, have it adjusted before further flight.

Mike Busch, 2008 National Aviation Maintenance Technician of the Year, has been a pilot for 44 years, logging more than 7,000 hours. He’s a certificated flight instructor and an airframe and powerplant mechanic with inspection authorization. E-mail questions to Mike at mike.busch@ savvyaviator.com. Mike also hosts free maintenance webinars on the first Wednesday of each month at 8 p.m. (central). To sign up or access the archives visit www.Savvymx.com/webinar.