COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes AD/DHC-8/61 Rudder Feel Assembly Springs 1/99 Applicability: DHC-8 aircraft, models 102, 103, 106, 201, 202, 301, 311, 314, and 315, serial numbers 3 through 520, excluding serial numbers 413, 450, 462, 463, 464, 465, 467, 468, 469, 473, 478, 479, 482, 487, 489, 491, 493, 495, 499, and 500. Requirement: 1. For all aircraft operating under Flight Manual Supplement 54 - Operation from narrow runways: 1. Inspect both rudder feel springs in accordance with Part III, Accomplishment Instructions, of Bombardier Inc. Alert Service Bulletin (ASB) A8-27-82. If either or both rudder feel springs are found to be of a non-conforming single rate configuration, operation from narrow runways in accordance with Flight Manual Supplement 54 is not permitted before accomplishment of Requirement 1.b. below and the following must be added to the LIMITATIONS section of the Flight Manual Supplement 54: "OPERATION FROM NARROW RUNWAYS IN ACCORDANCE WITH FLIGHT MANUAL SUPPLEMENT 54 IS NOT PERMITTED BEFORE BOTH RUDDER FEEL SPRINGS HAVE BEEN REPLACED IN ACCORDANCE WITH PART III, ACCOMPLISHMENT INSTRUCTIONS, OF ASB A8-27-82". This Flight Manual amendment task may be accomplished by inserting a copy of this Directive into the Limitations section of the Flight Manual. b. Replace both rudder feel springs in accordance with Part III, Accomplishment Instructions, of ASB A8-27-82. 2. For aircraft not operating under Flight Manual Supplement 54: Inspect both rudder feel springs in accordance with Part III, Accomplishment Instructions, of Bombardier Inc. ASB A8-27-82. If either or both springs are of a single rate configuration, both springs must be replaced. Note: Transport Canada AD CF-98-39 refers. Compliance: 1. a. Unless already accomplished, within 100 hours time in service after 28 January 1999. 1. b. At the next "C" check, or within 36 months, or prior to operating from narrow runways in accordance with Flight Manual Supplement 54, whichever occurs first after the Requirement 1.a. inspection. 2. Unless already accomplished, at the next "C" check or within 36 months after 28 January 1999, whichever occurs first. This Airworthiness Directive becomes effective on 28 January 1999. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Background: The rudder feel assembly incorporates two dual rate springs. However, a number of single rate springs were inadvertently introduced into some aircraft in production. Both single and dual rate springs have the same part number but differ in the breakout forces, where single rate springs require heavier than normal rudder pedal forces. A mix of single and dual rate springs produces an asymmetric rudder force condition which is particularly noticeable to the pilot when small rudder control inputs are required in gusty crosswind or single engine failure conditions. It is therefore necessary to restrict aircraft equipped with single rate springs from operating on narrow runways less than 18 metres wide.