Lycoming Piston Engines
AD/LYC/102
Amdt 2
Crankshaft Internal Inspection 11/98
Applicability: Textron Lycoming O-320 and O-360 series engines as detailed in Textron Lycoming Mandatory Service Bulletin (MSB) No. 505B, and not incorporating a front bore protective coating as detailed in Textron Lycoming Service Bulletin No. 530 or as approved by this authority.
Note 1: Engines applicable are engines fitted with hollow front bore crankshafts and installed in aircraft propelled by fixed pitch propellers.
Requirement: 1. Installed crankshafts: Carry out an internal inspection of the front bore of the crankshaft for evidence of corrosion in accordance with the inspection procedure detailed in Textron Lycoming MSB No. 505B. If there is no evidence of pitting corrosion in the front bore, no further action is required until the next inspection as detailed in the compliance requirements of this directive.
2. If in carrying out the internal inspection in accordance with Requirement 1 of this Directive there is evidence of pitting corrosion in the front bore:
(A) Carry out a Fluorescent Penetrant Inspection (FPI) in accordance with the FPI procedures detailed in Textron Lycoming MSB No. 505B, and
(B) Remove any evidence of pitting corrosion in accordance with a procedure approved by this authority, or CAR 35 authorised person, or remove the crankshaft from service.
(C) If in carrying out the FPI inspection a crankshaft is found to be cracked, the crankshaft is to be removed from service.
3. Spare crankshafts: Carry out an internal inspection of the front bore of the crankshaft for evidence of corrosion in accordance with the procedure detailed in Textron Lycoming MSB No. 505B, and
(A) Remove any evidence of pitting corrosion in accordance with a procedure approved by this Authority, or CAR 35 authorised person, and
(B) Carry out a Fluorescent Magnetic Particle Inspection (FMPI) of the crankshaft front bore in accordance with the engine manufacturer’s procedures or, the procedures detailed in CAO 108.8 Appendix 1.
(C) Apply a protective coating in accordance with the procedure detailed in Textron Lycoming MSB No. 530, or a procedure approved by this Authority or CAR 35 authorised person.
Note 2: FAA Airworthiness Directive 98-02-08 refers.
Compliance: Requirement 1: Unless previously accomplished;
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
(A) Applicable engines with a time in service since new, remanufacture or overhaul, of greater than 1,000 hours or 10 years:
(i) within 100 hours time in service or 12 months or at next removal of the crankshaft from the engine, whichever occurs first, and
(ii) thereafter at intervals not to exceed 5 calendar years.
(B) Applicable engines with a time in service since new, remanufacture or overhaul of less than 1,000 hours and 10 years:
(i) prior to exceeding 1,100 hours time in service or 11 years time in service or at next removal of the crankshaft from the engine, whichever occurs first, and
(ii) thereafter at intervals not to exceed 5 calendar years. Requirement 2, unless previously accomplished:
(A) before further flight.
(B) within 100 hours time in service.
(C) before further flight.
Requirement 3, in toto, unless previously accomplished: Prior to installation of a crankshaft in an engine.
This amendment becomes effective on 8 October 1998.
Background: The original issue of this directive was issued to require the inspection of hollow front bore crankshafts fitted with fixed pitch propellers. The requirement addresses CAA (UK) advice of two crankshaft failure events in flight. Amendment 1 to this Directive addresses:
- advice of industry concern with interpreting the compliance requirements of the original issue of this directive. In response, Requirement 1 has been amended to reflect; for engines with less than 1,000 hours operating time in service and less than 10 years calendar time in service, an inspection is required prior to exceeding 1,100 hours or 11 years time in service, whichever occurs first, or at next removal of the crankshaft from the engine, and
- industry reports of; in complying with the requirements of the original issue of this directive, evidence of pitting corrosion in a significant number of engines is resulting in aircraft being grounded. This amendment requires crankshafts with evidence of pitting corrosion to be inspected by FPI before further flight and the pitting corrosion removed, or the crankshaft replaced, within 100 hours time in service.
Amendment 2 to this Directive has been issued to include CAR 35 authorised persons in designing and approving inspection and repair schemes.
Amendment 1 of this Airworthiness Directive became effective on 18 June 1998. The original issue of this Airworthiness Directive became effective on 14 May 1998.