COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Radio Communication and Navigation Equipment AD/RAD/65 VN 411B VHF Navigation Receiver 8/99 Applicability: AlliedSignal (formerly Bendix and Bendix/King) VN 411B Very High frequency (VHF) Navigation Receivers as follows: BPN 3614004-4101 - all serial numbers, at Modification Status 18, 19 or 20; BPN/KPN 3614004-4101/066-1101-00 - all serial numbers, at Modification Status 18, 19 or 20; P/N 066-1101-00 - serial numbers up to and including 4229, at Modification Status 18, 19 or 20; and P/N 066-1101-31, -40 or -50 - serial numbers up to and including 10799, at Modification Status 19 or 20. Note: These VHF Navigation Receivers are known to be fitted to, but not limited to, the following aircraft models: Learjet 31A Fokker F27-50 BAe ATP Requirement: 1. Incorporate Modification 21 in accordance with either AlliedSignal Aerospace, Commercial Avionics Systems, Bendix/King Service Bulletin (SB) VN 411B-21 dated November 1996 or SB VN 411-21 Revision 1 dated April 1997. 2. VN 411 VHF Navigation Receivers listed in the Applicability Statement of this Directive that do not have Modification 21 incorporated must not be installed on any aeroplane. Note: FAA AD 99-12-06 Amdt 39-11190 refers. Compliance: 1. Either, within 90 calendar days after the effective date of this Directive or upon replacement or repair of the VHF Navigation Receiver, whichever occurs first. 2. As of the effective date of this Directive. This Airworthiness Directive becomes effective on 12 August 1999. Background: The United States Federal Aviation Administration has received reports of interference to the navigation receiver during landing operations. This Directive is intended to prevent interference from frequency modulated radio stations, which could cause both distortion of the navigation audio and deflection from the desired flight path.