Federal Aviation Administration March 25, 2008 – Federal Register Recent Federal Regulation Documents

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Bombardier Model DHC-8-400 series airplanes. The existing AD currently requires inspecting all barrel nuts to determine if the barrel nuts have a certain marking, inspecting affected bolts to determine if the bolts are pre-loaded correctly, and replacing all hardware if the pre-load is incorrect. For airplanes on which the pre-load is correct, the existing AD requires doing repetitive visual inspections for cracking of the barrel nuts and cradles and replacing all hardware for all cracked barrel nuts. The existing AD also requires replacement of all hardware for certain affected barrel nuts that do not have cracking, which would end the repetitive inspections for those airplanes. The existing AD also provides an optional replacement for all affected barrel nuts. This proposed AD would require replacement of all affected barrel nuts. This proposed AD results from reports of cracking in the barrel nuts at the four primary front spar wing-to-fuselage attachment joints. We are proposing this AD to detect and correct cracking of the barrel nuts at the wing front spar wing-to-fuselage joints, which could result in reduced structural integrity of the wing-to-fuselage attachments and consequent detachment of the wing.

We propose to adopt a new airworthiness directive (AD) for certain Hawker Beechcraft Corporation Model 390 airplanes. This proposed AD would require you to repetitively do a post-flight check (owner/operator holding at least a private pilot certificate checking for residual heat in the angle-of-attack (AOA) probes or an appropriately-rated mechanic doing a maintenance manual operational test of the heat of the AOA probes) after every flight and replace or modify (upload software) the stall warning AOA transmitters. This proposed AD results from reports of the potential for unannunciated loss of the heating function in the left-hand (LH) and right-hand (RH) stall warning AOA transmitters of Model 390 airplanes. We are proposing this AD to correct potentially inadequate stall warning with loss of stick pusher function.