AD 98-24-13 Airworthiness Directives; Eurocopter Deutschland GmbH (ECD) (Eurocopter) Model MBB-BK117 A-1, A-3, A-4, B-1, B-2, and C-1 Helicopters

Models named: MBB-BK117 A-1, A-3, A-4, B-1, B-2, C-1. Read the applicability below — it usually turns on serial or part numbers too.

Model MBB-BK117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters, certificated in any category. Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (f) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD.

Required as indicated, unless accomplished previously. To prevent failure of the tail boom vertical fin (vertical fin) and subsequent loss of control of the helicopter, accomplish the following: (a) Before further flight, remove the tail rotor drive shaft between the intermediate and tail rotor gearboxes and the yaw servo (if installed). Thoroughly clean the vertical fin spar and adjacent areas and visually inspect the following for cracks or loose rivets: (1) Both surfaces of the vertical fin spar, part number (P/N) 105-304061.03, P/N 1120-30406.03, or P/N 117-30423-03, paying particular attention to the area extending from the top edge of the third lightening hole from the top of the vertical fin spar to halfway between the fourth and fifth lightening hole (see Figure 1). (2) The skin and left-hand and right-hand frame sheets. BILLING CODE 4910-13-U [[Page 64178]] [GRAPHIC] [TIFF OMITTED] TR19NO98.002 BILLING CODE 4910-13-C (b) If a crack or loose rivet is found in the area described in paragraph (a) of this AD (see Figure 1), before further flight, repair in accordance with the Appendix, ``Repair of BK117 Vertical Fin'', to Eurocopter Alert Service Bulletin (ASB) MBB-BK 117 No. ASB-MBB-BK 117-30-106, Revision 4, dated December 19, 1997, or in accordance with Eurocopter ASB No. MBB-BK 117-30-106, Revision 3, dated May 5, 1997, except use of blind rivets is not permitted. Thereafter, perform the inspection described in paragraph (a) of this AD at intervals not to exceed 300 hours TIS. (c) If a crack or loose rivet is found in the area other than that described in paragraph (a) of this AD, including any crack that is found to extend into the skin, P/N 105-304011.18 or P/N 1120- 30402.08, before further flight, contact the Rotorcraft Standards Staff. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056. (d) If no crack or loose rivet is found as a result of the inspection required by paragraph (a) of this AD, until the repair is made in accordance with the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter ASB MBB-BK 117 No. ASB-MBB-BK 117-30-106, Revision 4, dated December 19, 1997, or in accordance with the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter ASB No. MBB-BK 117-30-106, Revision 3, dated May 5, 1997, except use of blind rivets is not permitted, perform the visual inspection required by paragraph (a) of [[Page 64179]] this AD at intervals not to exceed 100 hours TIS. (e) Within 600 hours TIS after October 24, 1997, accomplish the repair to the vertical fin in accordance with the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter ASB MBB-BK-117 No. ASB-MBB-BK 117-30-106, Revision 4, dated December 19, 1997, or in accordance with the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter ASB No. MBB-BK 117-30-106, Revision 3, dated May 5, 1997, except use of blind rivets is not permitted. If blind rivets were previously used to accomplish the vertical fin repair, they must be removed and replaced with solid rivets to comply with the requirements of this AD. Thereafter, perform the visual inspection required by paragraph (a) of this AD at intervals not to exceed 300 hours TIS. (f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff. (g) Special flight permits will not be issued. (h) The inspections and repairs shall be done in accordance with the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter Alert Service Bulletin MBB-BK 117-30-106, Revision 4, dated December 19, 1997, or in accordance with the Appendix, ``Repair of BK117 Vertical Fin,'' to Eurocopter Alert Service Bulletin No. MBB-BK 117-30-106, Revision 3, dated May 5, 1997, except use of blind rivets is not permitted. The incorporation by reference of Eurocopter Alert Service Bulletin No. MBB-BK 117-30-106, Revision 3, dated May 5, 1997, was approved previously by the Director of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as of October 24, 1997 (62 FR 52655, October 9, 1997). The incorporation by reference of Eurocopter Alert Service Bulletin MBB- BK 117-30-106, Revision 4, dated December 19, 1997, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. Note 3: Accomplishment of the requirements of Revision 3 of the referenced service bulletin, except for using solid rivets instead of blind rivets, or Revision 4 of the referenced service bulletin constitutes compliance with the requirements of this AD. (i) This amendment becomes effective on December 4, 1998. Note 4: The subject of this AD is addressed in Luftahrt- Bundesamt (Germany) AD 1997-144/3, effective May 11, 1998. Issued in Fort Worth, Texas, on November 12, 1998. Henry A. Armstrong, Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 98-30788 Filed 11-18-98; 8:45 am] BILLING CODE 4910-13-U