Lockheed Martin delivered the first 30 F-22As with an inadequate adhesive -- dubbed C493 -- for low observable (LO) coatings.
The manufacturer has since fixed the problem, but the first 30 airframes are stuck with the bad glue.
There's a reason we now know this bit of F-22A arcana. On November 1, a small patch of LO material sheared off the inlet for the right engine on takeoff. The material was sucked into the engine, causing more than $1.2 million in damage.
I reported about the mishap on this blog on Monday, a few days before the Air Combat Command released the accident investigation report. The report attirbutes the Class A mishap mainly to the poor adhesive used to attach the LO to the engine inlet.
That's one mystery solved.