COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 3100 (Jetstream) Series Aeroplanes AD/JETSTREAM/38 Amdt 2 Electrical Power Inverter Transfer Function 3/91 Applicability: Jetstream 3100 and 3200 aircraft as detailed in the Requirement document. Requirement: 1. Action in accordance with BAe Alert SB 24-A-JA 900443 Revision 2. Note 1. CAA (UK) Mandatory AD 31-04-90 also refers. Note 2. Flight Manual amendment A/3100-3107/20 also refers. 2. Action in accordance with BAe Alert SB 24-A-JM 7708 dated 2 March 1990. Compliance: Requirement 1: Prior to 16 May 1990. Requirement 2: Prior to 16 August 1990. Background: British Aerospace has advised of recent unacceptable AC power fluctuations which cause nuisance warnings and malfunctioning of essential flight instruments. BAe SB 24-A-JM 7708 introduces a modification to ensure that the operational inverter is isolated from the faulty inverter, and that stable AC power is available. BAe ASB 24-A-900443 Revision 2 introduces a modification which ensures that the captain and co pilot's essential flight instruments cannot be simultaneously connected to a faulty or unacceptable AC power source. Amendment 1 to this AD has been issued to: 1. Amend the effectivity; 2. To include advice that compliance with BAe SB 24-JM 7740 (refer AD/JETSTREAM/39) and BAe SB 24-JA900941 (optional) will reinstate the inverter transfer function and render compliance with SB 24-A-JA 900443 no longer necessary. Amendment 2 to this AD has been issued to advise of the promulgation of AD/JETSTREAM/39, which mandates compliance with BAe SB 24-JM 7740 requiring introduction of inverter Part No 1B350-1B1-3; and to clarify item 2 of Background paragraph 3 above.