Due to a perceived mistake in some of their work...

http://news.moneycentral.msn.com/ticker/article.aspx?Feed=AP&Date=20080401&ID=8420104&Symbol=AIR

"NEW YORK (AP) - Shares of AAR Corp. fell sharply Tuesday after details emerged that the aircraft service provider improperly maintained landing gear components on a number of Boeing jetliners"

But note that the mistake may not have been that bad...

http://news.moneycentral.msn.com/ticker/article.aspx?Feed=PR&Date=20080414&ID=8479121&Symbol=AIR


"The MOM reconfirms the enamel applied by AAR as a top coat to the inner diameter of landing gear truck beams "...to be equivalent to drawing finish requirements and can be considered acceptable subject to all other standard overhaul processes and applicable CMM [Component Maintenance Manual] instructions being followed at the time of the overhaul."