COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Gates Learjet 35 and 36 Series Aeroplanes AD/LEARJET 35/27 Amdt 1 Fluorescent Lighting Inverters 6/91 Applicability: All models as listed in the requirement document. Requirement: 1. Action in accordance with the technical requirements of FAA AD 91-03-08. Note 1: Learjet Alert Service Bulletins 31-33-2A; 35/36-33-5A; and 55-33-3A also refer. Note 2: If any fluorescent lighting system components referred to in the requirement documents above are found to be installed in any emergency lighting system, the correct operation of which is a mandatory certification requirement for the aircraft, then the disabling of such a system in accordance with an FAA AD is not permitted. 2. Any emergency lighting system the correct operation of which may have been disabled during compliance with FAA AD 91-03-08 (Requirement 1 above) are to be reactivated. Compliance: 1. For original issue of this directive, as specified in the Requirement document with an effective date of 12 February 1991. 2. For requirement 2 of this issue, prior to 13 September 1991. Background: There have been numerous reports of smoke in the aircraft cabin. The cause has been attributed to failure of certain fluorescent lighting system inverters to protect the wiring against open or short circuit conditions which may lead to arcing. This condition, if not corrected, could result in smoke and/or fire in the cabin, and electromagnetic interference. Amendment 1 to this AD is issued to include NOTE 2 to the requirement statement in order to prevent disabling of any emergency lighting system in accordance with an FAA AD, and to require re-activation of any emergency lighting systems, the correct operation of which is a mandatory certification requirement for the aircraft, which may have been disconnected during compliance with requirement 1.