FAA took another look at options to buffer the $82.6 million cost of a proposed airworthiness directive (AD) covering Engine Components Inc. (ECi) and Airmotive Engineering “Titan” cylinders found on 6,000 Continental 520 and 550 model reciprocating engines, but in a recent analysis says that it still finds the actions required in the proposed AD necessary to address its safety concerns.

FAA released the proposal last summer calling for repetitive inspections, replacement of cracked cylinders, and replacement of cylinder assemblies at reduced times-in-service. The NPRM also proposed banning installation of affected cylinder assemblies into any engine.

FAA cited concerns about numerous reports of cylinder head-to-barrel separations and cracked and leaking aluminum cylinder heads on the affected assemblies. The agency acknowledged the potential impact when it released the proposed AD, but said after a risk assessment, “we concluded that proceeding with this proposed AD to correct the unsafe condition was appropriate.”

The proposal has drawn strong objections from industry leaders and hundreds of commenters who believe the requirements lack safety justification given the costs involved and go beyond the scope of recommendations of the National Transportation Safety Board. Industry estimates were that the costs could be at least $12,000 for a single-engine operator and twice that for the twin-pistons.

The agency recently conducted an analysis under the Regulatory Flexibility Act (RFA) to determine how many small businesses would be affected by the AD and at what cost. Such an analysis is usually required when a proposed rule is anticipated to cover a large number of small businesses at high costs. The RFA also requires an agency to consider alternatives to a proposal that would alleviate the burden on small businesses.

Under the RFA, the agency considers three alternatives to the proposed requirements: do nothing; call for periodic inspections only with no forced removals; or call for removals with no period inspection requirement.

Do nothing was not an acceptable option, the agency says, “due to the number of failures of ECi cylinder head assemblies and the consequences of the failures.”

The second option, involving period inspections only, was recommended by the National Transportation Safety Board. But FAA says, “The rate of crack growth to failure is unknown, but has shown that it can be more rapid than the intervals of Part 43-mandated inspections.” The agency is also concerned that failures have grouped in both low and high-time engines.

As for the third alternative, removal and no periodic inspection, FAA says it has concerns that failures could still occur and “periodic inspections may find impending failures.”

While the proposed AD would cover thousands of operators, the RFA calls for a study of affected small businesses. FAA determined that the AD would affect 609 Part 135 operators classified as small businesses. The costs to these operators, depending on the work required and whether it would involve loss of the “asset,” could range between $22,000-$21 million, FAA estimates.

In addition, FAA estimates that “more than 5,000 smaller air services businesses” would be covered by the AD, estimating the costs of the basic requirements at $14,000. FAA said it could not determine the value of the affected assets of these businesses to estimate a total cost.

While comments aren’t due until May 12, the RFA already is drawing skepticism. Michael Busch, CEO of Savvy Aircraft Maintenance Management, calls FAA’s reasoning for not considering the alternatives “sheer pigheadedness. The crack growth rate is irrelevant, because it has been clearly demonstrated that the consequences of these failures are not only acceptable but quite benign.”

Busch notes that there have been no documented head-to-barrel separation failures in the past three years, and the failures that previously occurred did not cause a crash, fire or other safety hazard. “The whole notion of issuing this unprecedentedly expensive and oppressive AD to address a problem that represents no real threat to safety is a travesty,” he says.

Busch does not challenge the specifics of the RFA estimates, but says the overall cost of nearly $83 million is based on estimates that are “impossibly low.” He suggests FAA go back to the drawing board and come up with completely new estimates.