COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES SAAB SF340 Series Aeroplanes AD/SF340/23 Nacelle Cowling Door 3/91 Applicability: Model 340A and 340B with serial numbers; SAAB 340A-004 through -159. SAAB 340B-160 through -200. Requirement: Action in accordance with the technical requirements of Swedish LFV AD 1-042. Note: SAAB-SCANIA AB SB SAAB 340-71-35 refers. Compliance: As specified in the Requirement Document with revised effective date 21 March 1991. Background: The latch triggers on the nacelle fwd cowling doors have on some aircraft been trimmed to make the latch fit the form of the cowling surface. This could cause abnormal abrasion on the triggers, and might cause the latches to come unlocked, and result in cowling door opening during flight.