Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BELL 206/143 Amdt 2 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section. AD/BELL 206/143 Tail Boom Skin 5/2000 Amdt 3 DM Applicability: Applies to the following BHTC Model 206L series helicopters: Models Serial Numbers 206L 45004 through 45049, 45051 through 45153, and 46601 through 46617 206L-1 45154 through 45790 206L-3 51001 through 51612 206L-4 52001 through 52163, 52165 through 52212, and 52214 through 52216 Requirement: 1. Perform a visual inspection of the tail boom in accordance with BHTC Alert Service Bulletin (ASB) 206L-98-114 or ASB 206L-98-114 Revision A. 2. Accomplish the following: 1. Remove the upper and lower supports of the horizontal stabiliser in accordance with the applicable Maintenance Manual. b. In accordance with section 6.2 of Standard Practices Manual BHT-ALL-SPM, perform a one-time fluorescent penetrant inspection of the tail boom skin in the area at least 20 mm around the edges of the horizontal stabiliser openings. 3. Remove the support plates and visually inspect the entire edge of the horizontal stabiliser opening on both sides of the tail boom for cracks, using a 10x magnifying glass. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES If any crack is found on the tail boom skin as a result of the above required inspections, replace the tail boom before further flight. 4. Modify the tail boom in accordance with Parts I, II, and III of Alert Service Bulletin 206L-99-115 Revision D, dated 26 January 2000. Note: Transport Canada AD CF-98-42R3 refers. Compliance: 1. Unless the initial inspection is already accomplished, before further flight after 29 March 2000; thereafter, inspect before the first flight of each day in accordance with ASB 206L-98-114 Revision A. 2. Unless already accomplished, before further flight after 29 March 2000. 3. Within 100 hours time in service after 31 March 1999, and thereafter at intervals not to exceed 110 hours time in service. 4. Before 31 December 2000, unless already accomplished. Compliance with Requirement 4 of this Directive constitutes terminating action for Requirements 1, 2, and 3. The visual inspection required by this Directive may be performed by the pilot in command, in which case certification is to be made by entering AD/BELL 206/143 Amdt 3 against the daily inspection certification of the maintenance release. A copy of this Airworthiness Directive is to be kept in the aircraft. The compliance of the previous issue of this Directive remains unchanged for Requirement 3. This Amendment becomes effective on 29 March 2000. Background: There have been seven reports of cracks to the tail boom skin in the area of the horizontal stabiliser. The cracks were found by normal visual inspection. The average time accumulated on the tail booms was more than 2,000 hours; however, cracks could develop at any time. Pending further terminating action, on-going repetitive inspections are necessary. Amendment 1 was issued after a review of crack growth rates indicated a need to detect cracks earlier. This necessitates the use of non-destructive inspections of the tail boom skin under the support plates. Additionally, applicability was expanded for the Model 206L helicopters. The required inspections were an interim measure pending forthcoming mandatory installation of doublers on the tail boom skin around the horizontal stabiliser cutout. Amendment 2 mandated the reinforcement of the tail boom skin around the left horizontal stabiliser cutout. Amendment 3 is issued in response to a new TC AD which clarifies the applicability of Model 206 L serial numbers and extends the Requirement 4 compliance time. Amendment 2 of this Airworthiness Directive became effective on 7 October 1999. Amendment 1 of this Airworthiness Directive became effective on 31 March 1999. The original issue of this Airworthiness Directive became effective on 20 January 1999. Bernard Malcolm Hole Delegate of the Civil Aviation Safety Authority 23 March 2000 The above AD is notified in the Commonwealth of Australia Gazette on 29 March 2000.