COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Teledyne Continental Motors Piston Engines
AD/CON/45
Amdt 3
Camshaft Oil Transfer Holes 11/96
Applicability: All IO-520-B, -BB, -BA, -C, -CB, -M, -MB; TSIO-520-B, -BB, -BE, -D, -DB, -E, - EB, -J, -JB, -K, -KB, -L, -LB, -N, -NB, -UB, -VB and -WB model engines
incorporating camshaft part number (P/N) 629726 or SA629726 with suffix lettering A through Z or AA or AB to the part number (eg. 629726 A or SA629726 AB).
Requirement: To prevent fatigue cracking in the oil transfer recess of the rear cam bearing resulting in fracture of the camshaft and subsequent engine failure:
- Remove from service all camshafts P/N 629726 or SA629726 with suffix lettering A through Z and AA.
2. a. Inspect P/N 629726 AB or SA629726 AB camshafts in the vicinity of the oil transfer recess of the rear cam bearing (see Figure 1) for evidence of defects, and
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
2. b. Reject camshafts exhibiting any of the following defects:
(i) The radii at either end of the oil transfer recess is less than 0.762 mm (0.030 inches). Fig. 2, item 1 refers.
(ii) The radii at either end of the oil transfer recess is not continuous through 360 degrees of shaft rotation. Fig. 2, item 1 refers.
(iii) The oil transfer holes (2 off) are not approximately 90 degrees apart. Fig. 2, item 2 refers.
(iv) The oil transfer holes (2 off) cut into the radii at either end of the recess. Fig. 2, items 1 and 2 refer.
(v) Evidence of a rough surface finish and/or machine tool grooving in the oil transfer recess and around the oil transfer holes which could be considered as stress raising.
2. c. Following compliance with Requirement 2a and 2b; rework serviceable camshafts P/N 629726 AB or SA629726 AB in accordance with the procedures detailed in Teledyne Continental Motors Service Bulletin M86-14.
Compliance: 1. Unless previously accomplished in accordance with amendment 2 of this directive; at the next disassembly of the crankcase halves, effective on 10 October 1996.
2. Unless previously accomplished in accordance with amendment 2 of this directive:
* Installed camshafts: At the next disassembly of the crankcase halves, effective on 10 October 1996.
* Uninstalled camshafts (new or part life): Prior to installation in an engine, effective on 10 October 1996.
Background: This Directive was originally issued on 31 December 1984 to require the removal from service or inspection of certain part number camshafts. The requirement was in response to reports of engine failure events determined to have resulted from fatigue fracture of the subject part number camshaft. Amendment 1 was issued on 31 July 1985 to include camshafts manufactured by other than the engine manufacturer (PMA camshafts). Amendment 2 was issued on 31 July 1987 to reflect the manufacturer's issue of SB M86-14 on this subject. This amendment clarifies the inspection requirement and amends the compliance requirement from a "sunset" calendar date to an "at next access" requirement consistent with the manufacturer's published requirements.