Whether your engine is new, factory rebuilt or field overhauled, whoever built it should stand behind their work. But owners need to have reasonable expectations about what will and won't be covered under warranty. Unless a problem is due to an obvious manufacturing defect, don't expect it to be covered.

Over the past few months, I have been corresponding with an experienced aircraft owner from Western Maryland who is a partner in two airplanes: a 1979 Cessna 182 and a 2002 Cirrus SR-22. Unfortunately, both of these airplanes developed premature engine problems.

The Cessna 182 had all six cylinders on its TCM O-470-U engine replaced with Engine Components Inc. (ECi) steel cylinders. About 18 months and 150 hours later, after a particularly cold winter flying season in Western Maryland, oil analysis started showing increasingly high values for aluminum, chromium, iron and nickel. The cylinders were removed and sent back to ECi, who repaired them under warranty but declined to pay for the labor involved in removal and reinstallation. The owner was unhappy with this, and wrote to ask me whether I thought that ECi should be covering the labor under warranty.

Before responding, I took a look at ECi's written warranty policy for these cylinders. Here's what it says:

ECi hereby warrants each cylinder assembly which it ships with an accompanying FAA for 8130-3 or Return to Service tag to be free from defects in material and workmanship (parts and labor) under normal use and service for a period of one (1) year from its date of first operation. The date of first operation must not exceed one (1) year from the date of shipment from ECi and the first date of engine operation in an airframe must not exceed six (6) months from date of engine assembly. After one (1) year from the date of first operation, the warranty is pro-rated to the manufacturer's recommended time between overhaul (TBO) for the engine with a minimum accrual of forth (40) hours per months.

Adjustments for labor will be made in accordance with the manufacturers published allowances for cylinder replacement at the rate of $50 per hour. Adjustment for parts will be computed by dividing actual hours or forty (40) hours per month, whichever is greater, by TBO times ECi's original invoice amount. Total engine hours for pro-rata consideration will be made by ECi from complete operational records or log books which must be made available upon request.

The obligations of ECi under this warranty are limited, at the election of ECi to the repair or replacement of any part or parts which have been returned to Engine Components' factory with transportation charges prepaid and which, in the opinion of ECi, are defective.

Since the cylinders were 18 months old at the time of the warranty claim, ECi's warranty obligation was only to pay a pro-rated portion of replacement parts and labor, based on minimum usage of 40 hours per month (NOT the actual usage of just 8 hours per month). Given the engine's 1,500-hour TBO, ECi's obligation was to cover (1500-720)/1500 or 52% of the cost of removing, repairing, and reinstalling the cylinders. Furthermore, ECi's warranty obligation extends only to "normal use and service." ECi could easily have logically argued that the 182's cylinder problems were due to abnormal use (e.g., cold starts without proper preheating) and denied warranty coverage altogether.

Instead, ECi offered to cover 100% of the cost of repairing the six cylinders, asking the owners only to pick up their own mechanic's R&R labor (typically around $1,000). So I told the owner that I thought the company's warranty offer sounded fair to me, and suggested that he and his partners should be satisfied with it.

About four months later, I heard from the same aircraft owner once again. This time, he was asking about a different warranty issue involving his 2002 Cirrus SR-22. He said he and his partners had recently purchased the Cirrus from its original owner. The airplane was 14 months old and had just 67 hours total time since new when they acquired it. The new owners put 112 hours on the airplane in the next four months, whereupon the aircraft's TCM IO-550 engine developed a serious problem. Their mechanic found that an exhaust valve had stuck hard in its valve guide. The pushrod was bent, the valve rotator cap was galled, and the tappet was now stuck in its crankcase bore and refused to come out.

The mechanic called TCM to explain the situation, and requested that the problem be covered under warranty. TCM authorized the mechanic to remove the engine and ship it to the TCM factory in Mobile for inspection and repair. They indicated that they would repair the problem under warranty, and estimated that this would take 4 to 6 weeks plus shipping time. They deferred any decision about whether or not they would cover removal and reinstallation labor until they received the engine and had an opportunity to inspect it. (TCM's written new engine warranty covers parts for three years and labor for one year; the engine was 18 months old.)

The owner wrote me to say that he and his partners were sorely disappointed with TCM's warranty decision:

"We purchased the plane four months ago with 67 hours on it and find it hard to believe a 179-hour engine can be in this condition. Of course, the warranty says during the second year of ownership, only parts are covered, not labor. But based on the low-time and age on the engine, we believe we should get a new engine--and soon, not in two months--and that we should not incur any cost. I would like to request this from TCM, but we feel we don't have enough technical expertise to adequately make our case and understand whatever technical curve balls they may throw at us. Can you help?"

I responded that I felt TCM's offer to repair the engine under warranty sounded eminently reasonable to me, given that the company's only legal obligation for this 18-month-old engine was simply to furnish replacement parts. I understood the owner's disappointment about having the Cirrus down for two months or more, but the warranty doesn't cover downtime. I explained that it was rare for TCM to provide a replacement engine under warranty, and the only time I'd seen that happen was where an obvious manufacturing defect was involved. I indicated that stuck valves were usually caused by operational problems (such as excessively rich mixtures or cold starts without adequate pre-heating), and therefore I felt the chances of TCM being persuaded to replace the engine (rather than repair it) were close to zero.

Once again, I advised the owner that it sounded to me like the company was going well beyond its legal obligations under the written warranty, and that the owner and his partners should be satisfied.

Aircraft engine warranties are intended to protect the buyer against defects in materials or workmanship caused by the manufacturer or its suppliers. Given the extensive quality assurance procedures involved in the manufacture of aircraft engines, such defects are relatively rare. When they do occur, the manufacturers invariably bend over backwards to correct them and to pay for all associated costs including labor (and sometimes even downtime). Recent examples include crankshaft recalls by both TCM and Lycoming during the past several years, and with the recent recall of ECi Titan cylinders.

However, the vast majority of engine problems are owner-caused, not manufacturer-caused. TCM and Lycoming engines rarely fail to make TBO when flown frequently and regularly and operated carefully in accordance with manufacturer's recommendations and limitations. On the other hand, these engines often develop premature problems when flown sporadically and subjected to significant periods of disuse, or when abused by cold starting, overheating, dirt ingestion and so forth. Warranties are not intended to protect the buyer against such self-inflicted problems. That's why the written warranties incorporate strict time limits and accelerated pro-ration schedules. An engine that is flown only 67 hours in 14 months (like the IO-550 on the Cirrus at the time it was sold to its second owner) is an engine manufacturer's worst nightmare.

So let's get real about our expectations of what should be covered under warranty. When the manufacturer or overhauler screws up, the company should pay to make things right. When we screw up, we shouldn't expect the manufacturer to bail us out. If there's doubt about who's at fault, chances are it's us, not them.

Do you have a maintenance-related "war story" that you'd like to share with fellow aircraft owners? If you do, I'd love to hear from you. The most interesting stories I receive each month will be rewarded with highly prized Savvy Aviator coffee mugs, so please include your shipping address. Also be sure to let me know if you'd like me to "change the names to protect the innocent" when sharing your story.