AD/CESSNA 170/56 - Instrument Panel Light Dimming Rheostat (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

Cessna 170, 172, F172, FR172 and 175 Series Aeroplanes

AD/CESSNA 170/56 Instrument Panel Light Dimming Rheostat

3/94

Applicability: Cessna aircraft as follows;

Model Serial Numbers

172E, 172F, 172G, 172H, 172I and 172K (T-41A)

17250573 through 17259223

F172E, F172F, F172G and F172H F172-0019 through F17200754 FR172E, FR172F and FR172G FR17200001 through FR17200225 R172E, R172G and R172H (T-41B, T-41C and T-41D)

R172-0001 through R172-0452

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. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES