AD/ROTAX/6 - Camshaft Hardness Check (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

Rotax Piston Engines

AD/ROTAX/6 Camshaft Hardness Check 7/97 DM

Applicability: 1. Rotax 912 A-Series piston engines, S/N 4,380.661 up to S/N 4,380.701.

2. Rotax 912UL-Series piston engines, S/N 4,153.383 up to 4,153.500 and S/N 4,400.001 up to S/N 4,400.031.

Requirement: Inspection as prescribed in Bombardier Rotax Technical Bulletin 912-18 to be carried out. There are three steps to the Rotax directive, viz:

Step 1. Inspection of engine oil filter and magnetic drain plug before next flight. Abnormal results of this inspection will require an engine removal and return to Rotax for repair. If inspection satisfactory, proceed to Step 2.

Step 2. Within 100 operating hours after Step 1, measure camshaft hardness. If satisfactory, engine is clear of further action and normal operations may resume. If not satisfactory, repeat Step 1 every 100 operating hours until 600 operating hours reached and then take Step 3.

Step 3. Return engine to Rotax agent for replacement of the defective camshaft.

Compliance: Step 1: Before next flight and every 100 hrs after Step 2.

Step 2: 100 operating hours after Step 1.

Step 3: 600 hrs after Step 2.

This Airworthiness Directive becomes effective on 30 April 1997.

Background: Following an investigation into a report of unusual wear on a Rotax 912 camshaft, it was discovered that a batch of camshafts had been subject to deviations in material hardness during manufacture. This directive identifies the suspect engines by serial number and mandates inspection to identify defective camshafts, action to monitor in- service wear, and action to remove defective camshafts from service.