AD/DHE/18 Amdt 5 - Tapered Crankshaft Inspection
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
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De Havilland Piston Engines
AD/DHE/18
Amdt 5
Tapered Crankshaft Inspection 7/98
Applicability: Gipsy Major series engines fitted with a tapered crankshaft Requirement: 1. Insitu ultrasonic inspection:
In accordance with a procedure approved by the Authority, carry out an ultrasonic inspection of the crankshaft in the area forward of the thrust bearing flange.
2. Crankshaft inspection \- Pre Mod G2495 crankshafts:
(a) In accordance with a procedure approved by the Authority, carry out an ultrasonic inspection of the crankshaft in the area forward of the thrust bearing flange , and
(b) carry out a magnetic particle inspection of the entire crankshaft utilising the wet continuous technique applied in a manner that both longitudinal and circumferential cracking will be detected, CAO 108.8 Appendix 1 refers.
3. Crankshaft inspection \- Post Mod G2495 crankshafts:
(a) Remove the Mod G2495 thrust bearing location nut sleeve, and
(b) carry out a magnetic particle inspection of the entire crankshaft utilising the wet continuous technique applied in a manner that both longitudinal and circumferential cracking will be detected, CAO 108.8 Appendix 1 refers.
Compliance: Effective 18 June 1998:
Insitu ultrasonic inspection: Unless previously carried out;
(a) within 25 hours time in service or at the next maintenance release inspection, whichever occurs first, and then
(b) at 45 to 50 hours time in service following an inspection in accordance with Compliance requirement 1 (a).
Note 1: In service experience since the issue of AD/DHE/18 Amdt. 4 indicates the airworthiness of Gipsy Major tapered crankshafts in service can be reasonably established with two ultrasonic inspections. Therefore, engines in service which have already had two ultrasonic inspections of the tapered crankshaft, adequately satisfy Requirement 1 of this directive. No further insitu ultrasonic inspections are required.
2. Crankshaft inspection - Pre Mod G2495 crankshafts: Prior to installation of the crankshaft in an engine.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
3 Crankshaft inspection - Post Mod G2495 crankshafts. Prior to installation of the crankshaft in an engine.
This amendment becomes effective on 18 June 1998.
Background: This directive was originally issued to require a visual and a magnetic particle inspection (MPI) of the tapered crankshaft in the area forward of the thrust bearing flange. Amendment 4 replaced the visual inspection with repetitive insitu ultrasonic inspections. In service experience since the issue of Amdt. 4 has indicated the airworthiness of tapered crankshafts in service can be satisfactorily determined by two consecutive, insitu, ultrasonic inspections. In response, this amendment limits the insitu ultrasonic inspection requirement to two consecutive inspections.
In addition to the amended ultrasonic inspection compliance requirement, this amendment also includes a requirement to carry out an ultrasonic inspection of pre Mod G2495 crankshafts before installing that crankshaft in an engine. A Pre Mod G2495 crankshaft, recently inspected insitu by the ultrasonic inspection technique, was reported to be cracked in the area of the thrust bearing location nut threads. On removal of the crankshaft from the engine, and despite knowledge of the crack location, the crack could not be confirmed by MPI. An independent ultrasonic inspection confirmed the presence of a 6mm long by 3mm deep crack.
Amendment 4 of this Airworthiness Directive became effective on 22 July 1993. Amendment 3 of this Airworthiness Directive became effective on 30 May 1993. The original issue of this Airworthiness Directive became effective in August 1963.