COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Ryan ST Series Aeroplanes
AD/RYAN/3 Front Fin Spar Attachment 13/99
Applicability: Model ST-3KR aircraft, serial numbers 1001 through 2249.
Requirement: Perform a detailed visual inspection of the front fin spar for cracks at its attachment to the fuselage.
If no cracks are found, and if the spar has been reinforced at the critical section by means of a wood plug pressed into the end of the spar, no further action is required.
If cracks are found, the spar should be repaired by cutting the spar member approximately 3.25 inches above the lower bend and splicing on, by means of 3/16- inch bolts, a 1.125 by 0.058-inch 4130 steel spar replacement section.
Note 1: Ryan Service Bulletin 1044 covers the installation of the wood plug and Ryan Drawing SK-1879 covers the splice repair.
Note 2: FAA AD 46-06-01 refers.
Compliance: At the next periodic inspection after 30 December 1999, and thereafter at each periodic inspection.
This Airworthiness Directive becomes effective on 30 December 1999.
Background: The FAA requires on-going repetitive inspections of the front fin spar to fuselage attachment for cracking.