COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 150, F150, 152 & F152 Series Aeroplanes AD/CESSNA 150/44 Instrument Panel Light Dimming Rheostat 3/94 Applicability: Cessna aircraft as follows; Model Serial Numbers 150F, 150G, 150H and 150J 15061533 through 15071128 F150F, F150G, F150H and F150J F150-0001 through F150-0529 Requirement: Unless previously accomplished, replace the existing instrument panel light dimming rheostat (some installations will also require the fitting of a doubler) in accordance with the Accomplishment Instructions of Cessna Single Engine Service Bulletin SEB92-33 Revision 2 dated 10 September 1993. Note: FAA AD 93-24-15 Amdt 39-8764 refers. Compliance: Prior to 3 October 1994. Background: The FAA has advised of a report of an inflight fire in a Cessna Model 172. The fire was caused by a short in the electrical wiring controlled by the instrument panel light dimming rheostat. This Directive requires the rheostat to be replaced with an improved version, which is both current-limiting and heat-protected, thus decreasing the probability of an inflight fire being caused by a defective rheostat.