COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 47 (All Variants) Series Helicopters AD/BELL 47/88 Auxiliary Fuel System - Modification 5/83 Applicability: All Model 47G Series helicopters equipped with Soloy turbine conversion utilizing Chadwick C-27 auxiliary fuel systems installed per supplemental type certificate SH 139WE. Requirement: Part 1: Install a placard readily visible to the pilot in the cabin with the following annotation. WARNING "USABLE AUX. FUEL LIMITED TO HALF AVAILABLE QTY. AT T/O" Part 2: Install Chadwick C-27 FM flow monitor kit as applicable to Bell 47 Series. Note: Soloy Conversion SL-20-660 and Rev. 1. FAA AD 82-16-12. Chadwick SB 20- 81-01 Refer. Compliance: Part 1: Within 10 hours time in service after 10th April, 1983. Part 2: Within 300 hours time in service or 6 months after 31st May, 1983 whichever occurs first. Background: Tests conducted by the auxiliary fuel system manufacturer have shown that the loss of one auxiliary tank fuel pump will result in only half the usable auxiliary fuel being available in flight. When such a failure occurs no warning is provided.