Mar. 25 — American Eagle grounded 25 jets last week, causing 15 flight cancellations, after regulators questioned whether its planes underwent federally required inspections.
The airline later showed that a manufacturer's modifications addressed one of the potential problems. Eagle had correctly performed a separate check of the rudders, airline officials said.
Federal Aviation Administration officials in Fort Worth raised the questions during an audit to ensure compliance with airworthiness directives, which address potential safety problems.
The audit, which applies to all US carriers, wraps up this week. The FAA could announce results as soon as Monday.
The FAA announced the audit last week, after it fined Southwest Airlines $10.2 million for continuing to fly more than three dozen Boeing 737 jets that were out of compliance with airworthiness directives.
Southwest's jets missed inspections to detect fuselage cracks.
In Eagle's case, one inspection was meant to detect breaks or leaks in hydraulic lines and to make sure that cracks didn't develop where they pass through the airplane. Eagle's jets, made by Bombardier, underwent a modification during production that exempted them from the directive.
"There was confusion about whether an airworthiness directive applied, and it turned out that there was some equipment installed that satisfied ... the AD," FAA spokeswoman Laura Brown said.
The jets were grounded for about four hours on Friday evening, airline officials said. The airline decided to stop flying the planes until it could resolve the questions, even though "we knew we had completed these directives as specified," Eagle spokeswoman Andrea Huguely said.
Thirteen of the canceled flights were at Dallas/Fort Worth International Airport. The other two were at Chicago O'Hare International Airport, according to Eagle.
In the face of unprecedented federal scrutiny of airline maintenance, airlines are taking dramatic steps to prove compliance, including canceling flights to redo work they may have already performed.
The comprehensive audit could last three months
The FAA said it will seek the fine from Southwest for flying 46 jets during nine months in 2006 and 2007 without performing required inspections for cracks in the fuselage.
The recommendations come at a time when airlines are working to cut their maintenance costs.