Top FAA officials today stressed that there will be no leniency for carriers that have blatantly violated safety rules in the agency's ongoing investigation of airworthiness directive (AD) compliance.

"Forget about it, the aircraft is grounded," said FAA director of aircraft certification services John Hickey, when asked whether carriers who have discovered certain AD compliance issues might be able to work with the FAA to keep aircraft flying while closing out issues not related to safety of flight.

Hickey and FAA director of flight standards, James Ballough, discussed the issue today at the MRO North America conference in Ft. Lauderdale, Florida.

FAA is currently in the second phase of its review of AD compliance at US airlines, launched in the wake of revelations in March that Southwest Airlines continued flying 46 Boeing 737s with local FAA approval, long after certain metal fatigue safety checks were due.

Phase one of the review, which looked at 10 ADs per aircraft make and model at each US airline, revealed that only 1% of the more than 2,400 ADs reviewed were not complied with. In phase two, to be completed by the end of June, the FAA is reviewing 10% of all ADs across fleet types for all carriers.

Hickey says non-compliance is generally falling into three categories: cases of "very blunt noncompliance; workmanship issues, especially in the area of wiring systems; and slight deviations, akin to dotting the I's and crossing the T's".

Workmanship issues will likely result in groundings too, says Hickey, while slight deviations may be resolved with the help of an FAA "rapid response team".

In addition to the five-part plan FAA has already announced to strengthen the AD process -- including creating a safety issues reporting system and trying to eliminate ambiguities in how ADs are worded -- Hickey says the agency may also investigate the level of wiring system training that takes place at airlines and maintenance organizations and study whether its "lead airline" program is satisfactory.

Hickey's organization, which generates ADs for US-certificated aircraft, works with original equipment manufacturers and a "lead airline" as a test case before mandating an AD across the fleet.

He adds that some of the wiring ADs that have grounded large portions of the American Airlines fleet were issued before the "lead airline" program was implemented.

A focus on the clarity of ADs will also expand to foreign made aircraft.

Currently the FAA does not have to provide the same level of implementation review for the ADs issued by foreign countries and applied here through bilateral agreements.

"An AD by Airbus or EASA may not have the same level of user friendliness," Hickey explains.