AD/DH 104/1 - Fire Protection Modifications - Engine Nacelles (Cth)

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

DH 104 (Dove) Series Aeroplanes

AD/DH 104/1 Fire Protection Modifications - Engine Nacelles 8/71

Applicability: All models in transport category.

Requirement: 1. Modify the existing nacelle fire detection system as follows:

1.1 Replace the existing pyrotechnic cord type detector with a minimum of eight (8) unit detectors in approved locations in each engine bay or, alternatively, with an approved continuous type detector. All fire detectors shall be of an approved type.

1.2 Detector Circuits:

(a) Provide separate independent detector circuits for each nacelle.

(b) Install a test switch adjacent to the warning lights for each nacelle and arrange the detector circuit so that the test switch checks the circuit protection, the indicator lamps and the continuity of the detector wiring.

1.3 Indicators:

In addition to the existing warning lights for each nacelle install in the cockpit an audible fire-warning device common to both detector circuits.

2. Oil System:

Rework the following flexible oil lines to ensure that they are rendered fully fireproof:

(a) Hoses from oil tank to engine-driven oil pump.

(b) Hose from oil tank to propeller feathering pump.

3. Electric Cables:

3.1 Ensure that wiring forward of the firewall is PVC insulated glass braided cable to Specification AN-J-C-48a or other cable approved as fire-resistant class 11 for the following circuits:

(a) Fire detectors.

(b) Propeller feathering.

(c) Those sections of the starter motor circuit in which a fault could adversely affect propeller feathering.