2006-08-07: Upper tail rotor vertical gearbox (gearbox)

2006-08-07 Brantly Helicopter, Inc.: Amendment 39-14562. Docket No. FAA-2006-24447; Directorate Identifier 2005-SW-35-AD. Applicability: Model B-2, B-2A, and B-2B helicopters, serial number 2001 and larger, with a vertical shaft (shaft), part number (P/N) 249-10, or any serial-numbered helicopter with a shaft, P/N 249-10, that was purchased after 1994, certificated in any category. Compliance: Required as indicated, unless accomplished previously. To detect fatigue cracking of the shaft and prevent failure of the shaft and subsequent loss of control of the helicopter, accomplish the following: (a) Within the next 10 hours time-in-service (TIS) and before further flight after any hard landing or any main or tail rotor sudden stoppage: (1) Remove the tail rotor vertical gearbox (gearbox), P/N 278- 200; shaft, P/N 249-10; vertical shaft housing (housing), P/N 249-3; and the intermediate gearbox bushing (bushing), P/N 252-4, from the helicopter. (2) Inspectthe flange retainer, part number (P/N) 15-17, located at the top of the shaft housing for deformation and measure the inside diameter. Before further flight, replace the flange retainer with an airworthy flange retainer if the part is deformed or if the inside diameter is not 1.5050 to 1.5060 inches. (3) Inspect the housing, P/N 249-3, for deformation and measure the outer diameter at each end and at the center of its span. Replace the housing with an airworthy housing if: (i) The housing is deformed; (ii) Any outer diameter not on the flared end is not 1.497 to 1.500 inches; or (iii) The outer diameter of the flared end is not 1.844 to 1.875 inches. (4) Inspect the bushing, P/N 252-4, for nicks or scoring, and measure the bushing's length. If the length of the bushing is not .292 to .302 inch or if nicks or scoring is found, replace the bushing with an airworthy bushing before further flight. (5) Inspect the bevel pinion gear (gear), P/N 15-8, payingparticular attention to the bore, for nicks, scoring, burrs, or misalignment. Measure the diameter of the bolt hole and the bore. Before further flight, replace the gear with an airworthy gear if: (i) You find misalignment, (ii) You cannot remove all nicks, scoring, or burrs with light hand polishing using Scotch Brite (maroon or white) and maintain all tolerances and a 32 root mean square (rms) finish, (iii) The diameter of the bolt hole is not .1894 to .1899 inch, or (iv) The bore diameter is not .6248 to .6250 inch. (6) Inspect the shaft attachment bolt, P/N 15-201, that inserts into the pinion, and the attachment bolt, P/N 249-11, that inserts into the male coupling, for fretting or nicks in the area where the bolts contact the shaft and measure the grip diameter. If a bolt has fretting or nicks or if the grip diameter is not .1889 to .1894 inch, replace the bolt with an airworthy bolt before further flight. (7) Inspect the male coupling, P/N 249-9, paying particular attention to the bore for nicks, scoring, keyway elongation, burrs, or misalignment and measure the bolt hole diameter and the bore diameter. Before further flight, replace the male coupling with an airworthy male coupling if: (i) You find misalignment; (ii) The keyway has elongation; (iii) You cannot remove all nicks, scoring, or burrs with light hand polishing using Scotch Brite (maroon or white) and maintain all tolerances and a 32 rms finish; (iv) The diameter of the bolt hole is not .1894 to .1899 inch; or (v) The bore diameter is not .6250 to .6260 inch. (8) Inspect the shaft, P/N 249-10, for misalignment. Measure the diameter of the bolt holes. Inspect for straightness of the shaft by placing the shaft on a flat surface plate calibrated to work surface accuracy tolerance of .001 inch, rolling the shaft, and measuring the greatest gap between the shaft and the flat surface table. Magnetic particle inspect the shaft for a crack, payingparticular attention to the bolt holes. Visually inspect the shaft, paying particular attention to a circular area of .500 inch radius from the center of the bolt holes for the following damage: nicks, scoring, fretting, burrs, or misalignment. Before further flight, replace the shaft if: (i) You find misalignment, (ii) You cannot remove all nicks, scoring, fretting, or burrs with light hand polishing using Scotch Brite (maroon or white) and maintaining all tolerances and a 32 rms finish, (iii) The diameter of the bolt hole is not .1894 to .1899 inch, (iv) The outer diameter of the shaft is not .6240 to .6250 inch at all points, (v) The shaft is not straight and the maximum gap between the shaft and the flat surface table exceeds .007 inch, or (vi) You find a crack, a surface or subsurface discontinuity, or pitting. (9) Assemble and inspect the gearbox, P/N 278-200, the shaft, P/ N 249-10, and the housing, P/N 249-3, by following Part 2, paragraph 2.6 of Brantly International Inc. Service Bulletin No. 105, Revision A, dated August 3, 2005 (SB). Before assembling the pinion gear and the male coupling to the shaft, thoroughly inspect the bore for foreign objects or burrs. Clean and deburr the bore. If the assembly fails any inspection required by this paragraph, replace the gearbox, shaft, and housing with airworthy parts before further flight and before complying with the remainder of this AD. When the SB uses the term "check", for purposes of this AD, it means "inspect." Also, you are not required to contact the factory as stated in the SB. (b) Before installing the gearbox (upper): (i) Align and bolt down the intermediate gearbox, P/N 278-100, its cover, P/N 252-3, and the bushing, P/N 252-4, the long horizontal shaft housing, P/N 14-13, and its retainer flange, P/N 15-17, without making any adjustment for the gearbox (upper), shaft (vertical), or housing. Note 1: See the applicable maintenance manual for installation instructions. (c) Before further flight, install and inspect the gearbox, P/N 278-200, by following paragraphs 2.7 1) through 4) and Figure SB- 105-2 of the SB. If the gearbox fails any portion of the installation procedures or any inspection tolerance required by this paragraph, the installation is not airworthy and the helicopter is grounded until the installation complies with the requirements of this paragraph. (d) After an airworthy installation of the gearbox is complete, inspect the tail rotor rigging control and correct it, if necessary, before further flight. Note 2: See the applicable maintenance manual for tail rotor control rigging instructions. (e) Within 7 work days of conducting the inspections and measuring the affected parts, report any discrepancies for the item listed in Appendix A of this AD to the Rotorcraft Certification Office at the address specified in Appendix A. Information collection requirements contained in this AD have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. (f) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Rotorcraft Certification Office, FAA, for information about previously approved alternative methods of compliance. (g) Assemble, inspect, and install the gearbox and associated parts by following the specified portions of the instructions in Brantly International, Inc. Service Bulletin No. 105, Revision A, dated August 3, 2005. The Director of the Federal Register approved this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Brantly International, Inc., Wilbarger County Airport, 12399 Airport Drive, Vernon, TX 76384, telephone 940-552-5451. Copies may be inspected at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202- 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html . Appendix A--Results of Gearbox Assembly Inspection and Wear Measurements for the Brantly Model B-2, B-2A, and B-2B, Helicopters Point of Contact Information: Name:----------------------------------------------------------------- Company Name:--------------------------------------------------------- Address:-------------------------------------------------------------- City/State/Zip:------------------------------------------------------- Telephone:------------------------------------------------------------ Gearbox Part Inspection and Measurement Information (Report any discrepancies found per the AD):--------------------------------------- Flange Retainer part number (P/N) 15-17------------------------------- Shaft Housing, P/N 249-3---------------------------------------------- Bushing, P/N 252-4---------------------------------------------------- Bevel Pinion, P/N 15-8------------------------------------------------ Bolt, P/N 15-201------------------------------------------------------ Bolt 249-11----------------------------------------------------------- Male Coupling, P/N 249-9---------------------------------------------- Shaft, P/N 249-10----------------------------------------------------- Tail Rotor Gearbox Assembly, P/N 278-200------------------------------ Installation of Tail Rotor Gearbox Assembly--------------------------- Mail or Fax Results to: Federal Aviation Administration, ATTN: Marc Belhumeur, Rotorcraft Certification Office, Fort Worth, TX 76193-0170, FAX: (516) 222-5783. (h) This amendment becomes effective on May 2, 2006.