Commercial, Safety

FAA Bill May Reduce Time Lags for Issuance of Helo Airworthiness Directives

By Frank Wolfe | October 11, 2018
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CHC Helicopter-operated Airbus Helicopters AS332 L2. Photo courtesy of CHC

The FAA Reauthorization Act, P.L. 115-254, may reduce time lags between Europe and the United States in the issuance of similar airworthiness directives.

EASA at times will issue an airworthiness directive a year or more before the FAA issues its own AD after receiving public comments on the airworthiness issue in question.


Section 242 of the new FAA reauthorization law allows, but does not require, the FAA to accept airworthiness directives issued by foreign aviation safety agencies, such as EASA, if the U.S. has a bilateral aviation safety agreement (BASA) with a given entity or country.

The U.S. has such safety agreements with Europe, Brazil and Canada.

"Section 242 is important because it recognizes the countries the U.S. has a BASA with and where FAA has built its confidence in those countries’ aircraft design and certification," Walter Derosier, VP of engineering and maintenance at the General Aviation Manufacturers Association (GAMA), wrote in an email. "This improves the FAA’s ability to address airworthiness safety issues, including more quickly and efficiently adopting airworthiness directives for aircraft registered in the U.S. with a BASA-issued state of design."

In some cases, Europe and the U.S. procedures are in line, as when the FAA and EASA simultaneously issue emergency ADs on pressing safety matters with rotary- and fixed-wing fleets.

"Under current law and regulations, airworthiness directives are regulations, and as such they are subject to the due process requirements spelled out in the Administrative Procedures Act," Jason Dickstein, president of the Modification and Replacement Parts Association, wrote in an email. "This means that under normal circumstances, an airworthiness directive cannot be issued by the FAA unless the FAA publishes it in the Federal Register, seeks comments from the public, considers those comments and then publishes a final rule version of the airworthiness directive."

"I believe that the intent of Section 242 is to permit the FAA, as the U.S. aviation safety authority, to circumvent normal process in order to more rapidly implement a foreign airworthiness directive through acceptance of that foreign airworthiness directive," Dickstein wrote. "This is quite a departure from the traditional scope of the bilateral agreements because now the U.S. would be accepting foreign rulemaking as the basis for our own rulemaking. This could be a positive thing for safety, as it could make the process of publishing important safety information more efficient, but it could also open a door to mischief by circumventing norms of due process."

EASA provides for the direct adoption of FAA ADs. The FAA declined to comment on the reasons behind time lags in the issuance of EASA and FAA ADs.

"The delayed adoption by the FAA of Foreign State of Design ADs is caused by specific U.S. legal prerequisites, which the FAA must take into account before AD action is possible," EASA said in a statement. "These require the FAA to do a risk assessment, determine the cost per aircraft (parts, kit, man hours, etc.), as well as for the total fleet affected on the U.S. Register, and public consultation (Notice of Proposed Rulemaking or NPRM, equal to an EASA Proposed Airworthiness directive), prior to final rule issuance, unless there is a high risk and more urgent action is deemed necessary."

EASA said that "all these actions take considerable effort and time" and that the FAA "at this time is not legally allowed to accept 'as is' the EASA risk assessment, and therefore cannot adopt an EASA AD applicable to European designed products ... in the same way that EASA does with FAA ADs applicable to U.S. designed products."

"Any kind of ‘direct adoption’ (like EASA has in place) would require a change in U.S. regulation and therefore not be implemented in the near future," EASA said. "Unfortunately, the latest FAA reauthorization bill, which had this provision for the FAA to directly adopt foreign state of design ADs, has been amended by the U.S. Congress, and this provision has been withdrawn from the final text."

But FAA experts do, at times, come to different conclusions than EASA, and those agencies cede to the jurisdiction of national civil aviation authorities.

In April 2016, the fatal crash of an Airbus Helicopters EC225LP Super Puma in Norway led to the worldwide grounding of EC225LPs and AS332L2s in the Super Puma family in June of that year. But EASA ended the flight ban that October, contingent upon the replacement of transmission gears with more robust ones and the monitoring of the new components, and the FAA soon followed suit. But the civil aviation authorities in the U.K. and Norway left the grounding in place.

In 2017, Norway's aviation safety board issued 12 recommendations addressing weaknesses in EASA's certification specifications and Airbus Helicopters' type design of the EC225 LP, which is part of the H225 family.

One recommendation suggested that Airbus revise the type design "to improve the robustness, reliability and safety of the main gearbox in AS332 L2s and EC225 LPs." Ten of the board recommendations suggested updates to EASA's current regulations regarding certification and airworthiness standards on helicopters.

In 2014, EASA advised owners of some Airbus Helicopter models to inspect Shur-Lock nuts on the tail rotor drive flange to the main gearbox and take action, if loss of tightening torque was found. The FAA, however, did not issue an AD, as the agency determined that the loss of tightening torque may not create an unsafe condition.

Dickstein said the FAA public comment period has a purpose and may avoid unnecessary burdens on industry.

"Many years ago, I was involved in an airworthiness directive project that claimed that there were safety problems with a particular crankshaft and that it must be replaced with a different crankshaft," Dickstein wrote.

"Repair stations complained that the engine manufacturer was using the airworthiness directive to ‘capture’ the maintenance market in a way that was unfair. This 'unfair capture' argument was less relevant to the FAA than safety concerns, but it did motivate some repair stations to invest in studying the issue. So we started to look at the safety allegations and the data surrounding the populations of crankshafts. When we investigated the data, it turned out that the data showed that the new crankshafts had a higher incidence of failure than the older one it replaced, not a lower one. The proposed airworthiness directive would have reduced safety. In response to this data, the FAA withdrew the proposed airworthiness directive. This is part of the reason that the FAA invites the public to participate in rulemaking activities, in order to supplement the FAA’s resources and help the government reach the right decision for safety."

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