Cessna's three best-selling models are the 150/152, 172 Skyhawk and 182 Skylane. Together, they account for sales of nearly 100,000 aircraft. Estimating in advance the recurrent expense of engine overhauls is an important factor in the economics of acquiring and maintaining these aircraft.
The chief factor predicting the extent of overhaul work and its resultant cost is operating time on the engine since its last overhaul. This is expressed in hours (TBO) or time between overhauls. However, TBO should never take precedence over indications that engine work is necessary prior to the recommended scheduled overhaul. Other considerations include the overall condition of the engine, the date of its manufacture and any modifications performed on the engine since manufacture.
Elements of Overhaul
The defining requirement of an aircraft engine overhaul is that every engine must be totally disassembled and the wear and tear of each part evaluated separately. Consequently, a certain minimum cost is built in to the procedure, regardless of how well an engine has been maintained. Repair and replacement cost of individual parts vary according to their condition and tolerances.
Overhaul Schedule and Average Cost
Cessna 150/152s have a recommended TBO of 1,800 hours, with an average overhaul cost in 2011 of $20,000. The popular 172 Skylanes have a 2,000-hour TBO and overhauls running in the $20,000 range. The venerable 182, introduced in 1956, draws an average overhaul tab of $25,000 in 2011 after a TBO of just 1,500 hours.