The Five Dumbest Things on Wall Street This Week: April 4

4. AAR Maintains Innocence, Not Much Else

If you, like us and most major airlines, prefer your planes well maintained, you may not like this week's actions by AAR AIR.

On Tuesday, the Federal Aviation Administration expressed disappointment in the aircraft maintenance firm. According to an agency survey spanning most of the past decade, AAR has failed to use instruction manuals when repairing about 350 Boeing BA landing gear components.

Among the results of the oversight was the collapse of the gear on a US Airways LCC 757, as it refueled last October.

The FAA's note indicates that "AAR landing gear services approved truck beams for return to service that were not maintained in accordance with the manufacturer's maintenance manuals."

In an effort to clear up confusion, AAR issued a press release stating that even though its maintenance techniques were a little outside the box, it had presented the repair technique to Boeing, which, according to AAR, gave the botched job a thumbs-up.

But as the past several weeks have shown us, it's not the best time for a maintenance company to pass the buck. Airlines ranging from United UAUA to Southwest LUV are facing scrutiny from the FAA as they ground planes to keep them from falling apart midair.

Dumb-o-meter score: 82. "The FAA notice does not require taking any corrective action" on such landing-gear mishaps, AAR said in a press release. That's comforting.