Pilot checking fuel during a cold winter.

Update to engine failure accident advisory circular

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The FAA recently published an update to Advisory Circular (AC) 20-105, Reciprocating Engine Power-Loss Accident Prevention and Trend Monitoring.

This AC discusses the circumstances surrounding engine power-loss accidents and provides recommendations on how those accidents can be prevented. The AC also provides generic data collection charts to assist with setting up a reciprocating engine trend monitoring program to improve and track both engine and related system reliability over the recommended operating life of the engine.

Despite improvements in engine design and performance over the years, engine system malfunctions remain the defining event for personal flying accidents. Many of these accidents are the result of the pilot’s mismanagement of engine controls and improper preflight planning. The FAA believes many of these engine power-loss accidents can be avoided if the owner/operator institutes a comprehensive training program for pilots and mechanics and incorporates a trend monitoring program.

Checking for fuel contaminates is among the AC preflight recommendations.

Among the recommendations is for pilots to depart with each fuel tank filled to capacity when possible as an accurate measure of total fuel as fuel gauge accuracy varies widely, especially in smaller aircraft. When it is not practical to depart with full fuel tanks, pilots should employ a method of measuring the amount of usable fuel on board the aircraft that does not rely entirely on the fuel gauge, such as a pre-calibrated fuel dipstick.


The AC recommends departing with full fuel whenever possible.

Another cause of engine failure is allowing the engine to run past the manufacturer’s recommended TBO. TBO time is a reliable estimate of the number of hours the engine should perform reliably within the established engine parameters and still not exceed the service wear limits for overhaul for major component parts, such as the crankshaft, cam shaft, cylinders, connecting rods, and pistons. The FAA recommends TBO be observed by owners or operators becuase n overhaul at TBO will help ensure safety and reliability, and an engine overhaul at TBO is usually less expensive than an engine that has been run an additional 200 or 300 hours.

To access the complete AC 120-105(c), click here.

Flight Training Central Staff