The FAA has issued an airworthiness directive (AD) affecting some 100 Lycoming 360- and 540-series engines with ECi connecting rods installed. The AD, which becomes effective June 22, requires replacing certain ECi connecting rods at engine overhaul or by 2,000 hours time in service, whichever comes first.
AOPA had opposed the AD, primarily because there was no hard evidence that there was anything wrong with the ECi rods. There had been one failure recorded, which may have been due to oil starvation or improper installation.
Nevertheless, the FAA still insisted an unsafe condition existed in which there was a possibility that an engine with an ECi connecting rod (Part Number AEL11750, serial numbers 54/6 or lower) installed might stop running suddenly.
If there is any good news to this AD, it's that it actually affects a relatively small number of engines.
The FAA originally estimated that some 2,800 Lycomings had the connecting rods installed. The agency apparently missed the mark so widely because it asked the wrong question of the manufacturer.
While the company told the FAA it had sold some 2,800 connecting rods (an engine uses four or six rods, depending upon the number of cylinders), only about 400 rods were manufactured under ECi's parts manufacturing approval (PMA), an FAA-administered process for replacement parts in certificated aircraft. That meant that about 100 certificated engines might have received the replacement connecting rods. The other 2,400 rods were destined for experimental aircraft.
"We regret that the FAA never utilized the airworthiness concern process to ask the general aviation community if there truly is a problem with these connecting rods," said Luis Gutierrez, AOPA director of regulatory and certification policy. "An industry-supported study would have at least enabled the agency to get the numbers right."
May 22, 2006