A Notice of Proposed Rule Making (NPRM) issued by the FAA in the USA threatens the use of ECi cylinders on some Continental engines.
The NPRM follows an airworthiness directive (AD) requiring replacement of Titan brand ECi cylinders fitted to IO-520, TSIO-520 and IO-550 engines that may be subject to cracking at the base and the head dome. So far, the FAA has found 30 failures.
This action would force owners to carry out new overhauls on their aircraft regardless of the engine hours remaining, and has not pleased ECi's Mike Busch.
"The total cost to affected aircraft owners would be $83 million [US]," he points out in an update, "making this one of the most costly general aviation ADs in history. The FAA's rationale for this Draconian AD is that they've received reports of 30 head-to-barrel separations in ECi cylinders (out of a population of 30,000, a failure rate of 0.1%).
"This proposed AD is one of the most unwarranted, inappropriate, punitive and generally ill-conceived rulemaking actions I've ever seen come from the FAA."
According to Busch, there have been no accidents or injuries resulting from separation of the targeted cylinders, and the effects of separation in flight are minimal.
"Head separations are very rare, and when they happen the result is generally pretty harmless. The head separates from the barrel by less than an inch, the cylinder goes to zero compression, and the engine continues to run on five cylinders and make roughly 80% power."
Only aircraft such as Cessna 206s and Beech Bonanzas that have been fitted with ECi Titan cylinders bearing certain serial numbers will be affected.
The FAA AD can be read on the regulations.gov website.