AD/AIRCON/9 Amdt 8 - Combustion Type Cabin Heaters (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below repeals Airworthiness Directive (AD) AD/AIRCON/9 Amdt 7 and issues the following AD under subregulation 39.001 (1) of CASR 1998 and subsection 33 (3) of the Acts Interpretation Act 1901. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct an 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.

Airconditioning Equipment

AD/AIRCON/9 Amdt 8 Combustion Type Cabin Heaters 5/2016

Applicability:

All combustion type heaters fitted to aircraft to which Part 42 of CASR 1998 applies, other than the heaters for which AD/AIRCON/12 (as amended) is applicable.

Requirement:

1.    INSPECTION:

(a)   Inspect the combustion heater installation including any airframe mounted components necessary for heater operation for general condition and security; and

(b)   Inspect the hot air outlet ducting adjacent to the heater for freedom from exhaust contamination and corrosion; and

(c)   Clean the heater fuel filter and check the heater fuel system for loose connections and leaks using system pressure; and

(d)   Inspect heater drain lines for freedom from obstructions; and

(e)   Inspect and adjust spark plugs and contact breaker points where necessary.

2.    FUNCTIONAL TEST:

Carry out a functional check during which carbon monoxide (CO) level is to be measured in the heated air entering the cabin. Quantitative CO measurement must be used to confirm CO level entering cabin is less than 1 part per 20,000 parts of air.

If the heater fails this test, disable the heater per Requirement 4 or replace/repair the heater.

3.    OVERHAUL:

Overhaul the heater and the associated airframe mounted components necessary for the heater operation.

4.    DISABLE:

Disable the heater as follows, subject to Minimum Equipment List (MEL) requirements or regulation 37 of the Civil Aviation Regulations 1988:

(a)   Cap the fuel supply line; and

(b)   Disconnect the electrical power and ensure that the connections are properly secured to reduce the possibility of electrical spark or structural damage: and

(c)   Inspect and test to ensure that the cabin heater system is disabled and the cabin fans are operative; and

(d)   Ensure that no other aircraft system is affected by this action; and

(e)   Ensure there are no fuel leaks; and

(f)   Fabricate a placard with the words: “System Inoperative ”and install the placard at the heater control valve within the pilot’s clear view.

Note 1:Permanent deactivation of the heater will require approved modification data including internal inspection and functional tests before return to service.

Compliance:

1.    Unless previously accomplished, within 100 heater hours or 12 calendar months time in service (TIS) whichever occurs first after the effective date of this AD; and thereafter at intervals not exceeding 100 heater hours or 24 months time in service whichever occurs first.

2.    Unless previously accomplished, within 100 heater hours or 12 calendar months time in service (TIS) whichever occurs first after the effective date of this AD; and thereafter at intervals not exceeding 100 heater hours or 24 months time in service whichever occurs first.

3.    Per heater manufacturer’s recommendations. Where heater manufacturers’ recommendations are not available, at intervals not to exceed 500 heater hours since overhaul or 8 years since overhaul whichever occurs first.

4.    As required per Requirement 2.

Note 2:  If a heater hour meter is not installed, the aircraft hours may be divided in half to provide the heater TIS hours.

The effective date of this AD is 26 February 2016.

Background:

Amendment 7 deleted the calendar time overhaul requirements for heaters where the manufacturer has recommended overhaul periods. In addition, conditions were added to the disabling of heaters.

Amendment 8 is issued to limit the AD’s applicability to Part 42 aircraft only. This AD will be repealed after the requirements are incorporated into a future amendment of the Part 42 Manual of Standards.

Pieter van Dijk
Delegate of the Civil Aviation Safety Authority

22 February 2016