COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Pratt and Whitney Turbine Engines - JT9D Series AD/JT9D/19 Amdt 2 Surge Margin Improvements 3/93 Applicability: JT9D-7R4D, E series engines installed in Boeing B767 aircraft. Requirement: Action in accordance with FAA Airworthiness Directive 90-14-08, paragraphs (a), (b), (c), (d), (e), (f), (g), (h) and (i). For the purpose of this Directive, compliance with the requirements of PWA SB JT9D-7R4-75-101 is deemed to be an alternative method of compliance with the requirements of FAA AD 90-14-08, paragraph (d), (2). Compliance: As detailed in the requirement document, with an effective date of 4 March 1993. Background: This Directive has been amended to reflect the release of an additional procedure which, if incorporated, will improve the JT9D-7R4 surge margin.