85-26-06 BELL HELICOPTER TEXTRON, INC.: Amendment 39-5193. Applies to Model 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, and 206L-3 helicopters certificated in any category. (Airworthiness Docket No. 83-ASW-53.) \n\n\tCompliance is required as indicated (unless already accomplished). \n\n\tTo prevent possible loss of the tail rotor tip block and resulting tail rotor imbalance which could lead to tail rotor gearbox and stud failure and subsequent separation of the tail rotor gearbox from the helicopter tailboom, accomplish the following: \n\n\t(a)\tWithin the next 7 days after the effective date of this AD, and thereafter at intervals not to exceed 7 days, check tail rotor blades, Part Numbers (P/N) 206-016-201-001, - 103, and -107, for serviceability with special emphasis on the tip block area as follows (see Figure 1): \n\n\t\t(1)\tVisually check for corroded or missing rivet heads. \n\n\t\t(2)\tVisually check for rivet heads that have pulled through the skin shell in the tip block area.(3)\tVisually check for voids or separations between the skin shell and tip block. \n\n\t\t(4)\tCheck for any movement or displacement of the tip block outboard of the tip of the skin shell. \n\n\t(b)\tThe check required by paragraph (a) of this AD is not considered to be maintenance or preventive maintenance. However, the person performing this check shall make an entry in the aircraft's maintenance records containing the following information: \n\n\t\t(1)\tIf no discrepancies are noted, make an entry referencing the check required by paragraph (a) of this AD, the name of the person who performed the check, the date the check was accomplished, the signature, certificate number, and kind of certificate held by the person performing the check. \n\n\t\t(2)\tIf any discrepancies are noted, make an entry referencing the check as required in paragraph (a) of this AD, the name of the person who performed the check, the date the check was accomplished, and the nature of the discrepancy. In addition tothis entry, the inspection required by paragraph (d) of this AD must be performed before further flight. \n\n\t(c)\tThe checks required by paragraph (a) of this AD may be performed by the pilot provided his logbook is endorsed by an appropriately rated mechanic stating that the pilot has been properly trained to conduct the check. \n\n\t(d)\tWithin the next 100 hours time in service after the effective date of this AD, and thereafter at intervals not to exceed 100 hours time in service, inspect tail rotor blades, P/N's 206-016-201-001, -103, and -107 for serviceability with special emphasis on the tip block area as follows (see Figure 1): \n\n\t\t(1)\tVisually inspect for corroded rivets and/or missing rivet heads. \n\n\t\t(2)\tReplace corroded or missing rivets per instructions in paragraph (e) of this AD before further flight. \n\n\t\t(3)\tVisually inspect for rivet heads that have pulled through the skin shell in the tip block area. \n\n\tNOTE: A rivet head that has pulled through the skin will require replacement of the blade before further flight. \n\n\t\t(4)\tVisually inspect for voids or gaps between the shell and the tip block. Limits for voids or gaps between the shell and the tip block are as follows: \n\n\t\t\t(i)\tA void (or gap) no wider than 0.25 inch (chordwise) at the leading edge is acceptable but must be sealed (see Figure 1). Seal with EC-2216 or EA934 in accordance with the appropriate Model 206 maintenance manual or FAA-approved equivalent. \n\n\t\t\t(ii)\tA void (or gap) no wider than 0.12 inch (chordwise) between the shell and the aft end of the tip block is acceptable but must be sealed (see Figure 1). Seal with EC-2216 or EA934 in accordance with the appropriate Model 206 maintenance manual or FAA- approved equivalent. \n\n\t\t\t(iii)\tWith the exception of paragraphs (d)(4)(i) and (d)(4)(ii) of this AD, voids between the shell and the tip block that are visible at the top are unacceptable. \n\n\t\t\t(iv)\tReplace any blade with voids in excess of these limitations before further flight. \n\n\t\t\t(v)\tAny movement or displacement of the tip block outboard of the tip of the skin shell shall require replacement of the blade before further flight. \n\n\t(e)\tWithin the next 30 days after the effective date of this AD, replace the five aluminum rivets in the tail rotor tip block area with five titanium brazier head rivets, P/N CSR903B4-14, and special washers, P/N 206-016-213-101, in accordance with Part II of Bell Alert Service Bulletin 206-85-28, Rev. "B," dated June 21, 1985, or 206L-85-34, Rev. "B," dated June 21, 1985, whichever applies. \n\n\tNOTE: Tail rotor blades modified in accordance with Part II of the Bell Alert Service Bulletin 206L-85-34, Rev. "A," dated April 2, 1985, or Bell Alert Service Bulletin 206-85-28, Rev. "A," dated April 2, 1985, have been determined to be in compliance with the requirements of this AD and the weekly check required in paragraph (a) of this AD is no longer in effect for modified blades. However, the 100-hour repetitive inspection described in paragraph (d) of this AD remains in effect. \n\n\t(f)\tUpon compliance with paragraph (e) of this AD, the weekly check as described in paragraph (a) of this AD is no longer in effect. However, the 100-hour repetitive inspection described in paragraph (d) of this AD remains in effect. \n\n\t(g)\tIn accordance with FAR Sections 21.197 and 21.199, the helicopter may be flown to a base where the requirements of this AD can be accomplished. \n\n\t(h)\tAny alternative method of compliance which provides an equivalent level of safety with this AD may be used when approved by the Manager, Helicopter Certification Branch, Southwest Region, Federal Aviation Administration. \n\n\tThe manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copiesupon request to Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101. The documents also may be examined in Room 158, Building 3B, Office of the Regional Counsel, FAA, Southwest Region, 4400 Blue Mound Road, Fort Worth, Texas 76106, between 8 a.m. and 4 p.m., weekdays, except Federal holidays. \n\n\tThis AD supersedes AD 82-17-04, Amendment 39-4819 as amended by Amendment 39- 4890. \n\n\tThis amendment becomes effective January 31, 1986. \n\n\n\n\n\t\t\t\t\tFIGURE 1\tAD 85-26-06