AD/Cessna 525/8 Firewall Sealant (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Cessna 525 Series Aeroplanes

AD/CESSNA 525/8 Firewall Sealant 8/2008

Applicability:

Model 525 aircraft, serial numbers 525-0600 through 525-0662.

Requirement:

Inspect between the 6352225 aft firewall assembly and 6352226 seal assembly for missing firewall sealant, in accordance with Cessna Aircraft Company Citation Service Letter SL525-71-05 Revision 1, dated 6 February 2008, or later FAA approved revision.

If firewall sealant is found to be missing between the aft firewall and seal assembly, before further flight, seal the gap between the aft firewall and seal assembly with U000117S firewall sealant in accordance with the Requirement document.

Note:  FAA AD 2008-12-01 Amdt 39-15544 refers.

Compliance:

Within 60 hours time in service or 60 days after 31 July 2008, whichever occurs first.

This Airworthiness Directive becomes effective on 31 July 2008.

Background:

The FAA received a report that firewall sealant may not have been applied between the aft firewall assembly and seal assembly during manufacture of certain Model 525 aircraft.  Such a condition could result in failure of the fire extinguishing system to prevent the spread of fire through the firewall gap, and could lead to an uncontrolled fire.

David Villiers
Delegate of the Civil Aviation Safety Authority

18 June 2008