1AD/IAI-W/19 - Hydraulic Low Pressure Warning System

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Israel Aircraft Industries 1123 and 1124 (Westwind) Series Aeroplanes

AD/IAI-W/19 Hydraulic Low Pressure Warning System 13/98

Applicability: Model 1124 and 1124A aeroplanes all serial numbers.

Requirement: Modify the electrical wiring and install an independent circuit breaker for the hydraulic low pressure warning system, together with an associated label, on the overhead panel in accordance with Israel Aircraft Industries 1124-Westwind Alert Service Bulletin No 1124-29A-140 dated 15 August 1998.

Note: Israel CAA AD 29-98-09-01 refers.

Compliance: Within 400 hours time in service, but no later than 31 October 1999. This Airworthiness Directive becomes effective on 3 December 1998.

Background: The nose wheel steering and the hydraulic low pressure warning electrical circuits were connected to the same circuit breaker. A failure in the steering circuit causing the circuit breaker to trip results in a loss of warning of low hydraulic pressure, creating an unsafe condition.

This directive corrects the unsafe condition by precluding the possibility of a loss of warning of low hydraulic pressure during malfunction of the nose wheel steering electrical circuit.