Commonwealth legislation

AD/CESSNA 170/56 - Instrument Panel Light Dimming Rheostat

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legislative instrument

Plain English Summary

3/10 complexity

Requires replacement of the instrument-panel light dimming rheostat (and, where necessary, fitting a doubler) on specified Cessna 170/172/175-series aircraft, to be done per Cessna Single Engine Service Bulletin SEB92-33 Revision 2. The stated purpose is to reduce the risk of an inflight fire by installing a current‑limiting, heat‑protected rheostat; owners/operators must arrange and pay for the replacement and any associated maintenance before the directive’s compliance date.

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AD/CESSNA 170/56 - Instrument Panel Light Dimming Rheostat

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source
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

View image in the official source

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/CESSNA 170/56 - Instrument Panel Light Dimming Rheostat

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

Note: FAA AD 93-24-15 Amdt 39-8764 refers.

Compliance: Prior to 3 October 1994.

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES