The FAA is simply determined to get rid of thousands of ECI cylinders used on big-bore Continental engines.
Last August the FAA issued a proposed AD that would have required approximately 36,000 aftermarket cylinders built by ECI to be junked, most of them after only 500 hours of operation. The proposed rule also called for repetitive inspections and grouped cylinders by serial number.
The NPRM drew many, many comments, most of them against the proposed AD. But earlier in January the FAA came right back at airplane owners with a revised proposal that essentially requires the cylinders to be removed from the engine after 1,000 hours of operation.
It’s true that 1,000 hours is better than 500, but to me it still isn’t necessary to accomplish the FAA’s objective. Even the NTSB, not exactly a devil may care outfit when it comes to safety, commented that the cylinders should be allowed to fly on until recommended TBO. But the FAA has again ignored the NTSB’s advice, and the advice of everyone else who commented.
The FAA says it has determined that the affected ECI cylinders suffer head separation at a much higher rate than other cylinders. There have been a few instances where the aluminum head did crack and break free from the steel cylinder barrel. Obviously that cylinder no longer functions, and there is at least some risk of fire because fuel and probably spark is still being fed to the failed cylinder head. By there have been no fatal accidents caused by these failures.
It’s impossible for the FAA to know with certainty anything about the failure rates of any cylinder or piston engine component because the data just doesn’t exist. The FAA does get service difficulty reports if shops take the time to file them, but there is absolutely no way to know how much of the universe the reports represent. It’s just hit and miss.
But, I fear the evidence fight is over. For whatever reasons the FAA is absolutely determined that the affected ECI cylinders are “unsafe”–the FAA word. So the FAA objective should be to remove the cylinders from engines in the least disruptive and costly way.
Here is how that can be accomplished. Issue an AD that forbids any ECI cylinder in the affected group from ever being reinstalled in any engine after it has been removed for any reason.
The fundamental problem is that piston engine parts are certified without life limits and without any requirement to document time in service. A cylinder, for example, remains airworthy as long as a licensed mechanic or repair station says it is. And that cylinder can be repaired in all kinds of ways and be returned to an airworthy condition.
But absolutely nothing is known about cylinders once they are removed from an engine because there is no requirement to record anything. For example, at the last annual two cylinders on my high-time engine were simply worn out. The shop bought two overhauled cylinders to replace them. The overhauled cylinders came with the required yellow tag saying they had been repaired and inspected and are airworthy.
But nobody has any clue how many hours are on those cylinders, or even what type of engine they came from. Those cylinders could have been on a turbocharged engine with the higher heat and stress involved but are now on my naturally aspirated engine. They could have come from a 520 and are now on my 550 engine. And the cylinders that came off my engine went to that overhaul shop as a “core” and were most likely repaired and are on yet another engine.
It is this “certified forever” concept of piston engine parts that is, or should be, the issue with ECI cylinders. Without an AD the ECI cylinders the FAA is worried about could fly on being repaired and overhauled repeatedly with no records kept about time in service.
My idea of an AD that simply doesn’t allow reinstallation of one of the covered cylinders would cost owners only the “core” credit we get when a cylinder is replaced or the engine is overhauled. The core credit is typically a few hundred dollars because the overhaul shop that sells you the repaired cylinder needs your old cylinder–the core–to repair and resell. So in this case you wouldn’t have a cylinder to exchange so you would be charged the core credit.
The reality is that many, even most, cylinders will develop some sort of problem during their run between major overhauls. Leaking valves are common, but rings and cylinder barrels wear, valve guides wear and so on. That means the affected ECI cylinder replacement would be spread out. When a cylinder needed to come off for any work that would be it. The cylinder would be retired. And the cost of complying with the AD would be the cost of the core credit as each cylinder is retired.
At major overhaul time all six cylinders would be trashed. The extra cost to the airplane owner would be six core credits. That’s a lot, but still so much better than junking all of your cylinders at the arbitrary 1,000 hours the FAA is proposing.
You can read and comment on the proposed ECI cylinder AD here: http://www.regulations.gov/#!documentDetail;D=FAA-2012-0002-0600
Comments are open until February 23. It may make you feel better to comment that the AD is simply not necessary, but the way the FAA blew off all of those thoughtful and supported comments in the first round I just don’t expect the AD to go away. I think the best we can hope for is to fly the affected cylinders until they need work, and then throw them away when they come off the engine. That’s bad, but not as bad as what the FAA is proposing.