99-17-03 BELL HELICOPTER TEXTRON, INC.: Amendment 39-11252; Docket No. 98- SW-73-AD; Issued August 4, 1999. Supersedes 97-18-11, Amendment 39-10520, Docket No. 97-SW-32-AD which superseded Priority Letter 97-18-01 issued August 19, 1997.
Applicability: Model 204B helicopters with vertical fin spar (fin spar), part number (P/N) 205-030-899-001, -089, P/N 205-030-846-001, -003, -047-, 049, or P/N 204-030-825-063, -065, installed, and Model 205A and 205A-1 helicopters, with fin spar, P/N 205-030-899-101, P/N 205-030-846-087, -089, or P/N 205-032-851-003, -007, -009, installed, certificated in any category.
NOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise 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/operatormust request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To prevent failure of the fin spar, loss of the tail rotor, and subsequent loss of control of the helicopter, accomplish the following:
(a) For Model 204B helicopters:
(1) Within 8 hours time-in-service (TIS), modify the vertical fin and visually inspect the fin spar for cracks in accordance with Part I (A1), paragraphs 1 through 5 of Bell Helicopter Textron (BHTI) Alert Service Bulletin (ASB) 204B-98-50, dated October 22, 1998.
(i) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(ii) After inspection, apply MIL-PRF-81352 TYI clear lacquer or equivalent to the inside of the two lower rivet holes and on the surface where paint and primer were removed. Spray, brush, or wipe on a protective coat of MIL-C-16173, Grade 2, or equivalent, over the clear lacquer. To facilitate subsequent inspections, do not replace the two lower rivets. See Figure 2 of BHTI ASB 204B-98-50, dated October 22, 1998.
NOTE 2: BHTI-MED-SRM-1, pages 3-36 through 3-38, pertain to the installation of Hi- Loks.
(iii) Before drilling or reaming, inspect all holes in the spar cap where rivets were removed for short edge distance. An existing edge distance less than 1.5 times the diameter of the drill or reamed hole must have FAA approval of the reworked area before proceeding.
(iv) Fasten the forward left-hand fin skin to the spar assembly using Hi-Loks and blind rivets as specified in Figure 2 of BHTI ASB 204B-98-50, dated October 22, 1998.
(v) Refinish the reworked area.
(2) After initial modification and inspection of the fin, thereafter inspect the fin spar for cracks at intervals not to exceed 8 hours TIS as follows:
(i) Accomplish Part I (A2), paragraphs 1 through 3 of BHTI ASB 204B-98-50, dated October 22, 1998.
(ii) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(iii) After inspection, accomplish Part I (A2), paragraphs 5 and 6 of BHTI ASB 204B-98-50, dated October 22, 1998.
(3) Within 25 hours TIS, modify and inspect the vertical fin as follows:
(i) Accomplish Part I (C1), paragraph 1 of BHTI ASB 204B-98-50, dated October 22, 1998.
(ii) Remove sufficient rivets from the bottom row of the forward left-hand fin skin to allow trimming of the forward left-hand fin skin along the "skin cutline", approximately fin station 64.31 (see Figure 2 of BHTI ASB 204B-98-50, dated October 22, 1998).
(iii) Before drilling or reaming, inspect all holes in the spar cap where rivets were removed for short edge distance. An existing edge distance less than 1.5 times the diameter of the drill or reamed hole must have FAA approval of the reworked area before proceeding.
(iv) Accomplish Part I (C1), paragraphs 3, 4, and 6 of BHTI ASB 204B-98-50, dated October 22, 1998.
(v) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(vi) Accomplish Part I (C1), paragraphs 10 through 14 of BHTI ASB 204B-98-50, dated October 22, 1998.
(4) After the initial modification and dye-penetrant inspection of the fin spar, thereafter at intervals not to exceed 300 hours TIS, inspect the fin spar as follows:
(i) Accomplish Part I (C2), paragraphs 1, 2, 3, 4, 5, and 7 of BHTI ASB 204B-98-50, dated October 22, 1998.
(ii) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(iii) Accomplish Part I (C2), paragraphs 11 through 14 of BHTI ASB 204B-98-50, dated October 22, 1998.
(5) Within 25 hours TIS, and thereafter at intervals not to exceed 300 hours TIS, inspect the fin spar as follows:
(i) Accomplish Part I (B), paragraphs 1 through 13 of BHTI ASB 204B-98-50, dated October 22, 1998.
(ii) Repair any disbonding discovered during the inspection before further flight.
(6) Within 12 calendar months, remove fin spar P/N 205-030-899-001, or - 089, or P/N 205-030-846-001, -003, -047, or -049, or P/N 204-030-825-063, or -065. Replace it with an airworthy fin spar configuration that has been demonstrated to the FAA to satisfy the structural fatigue requirements of repeated high torque events and is approved by the Manager, Rotorcraft Standards Staff.
(7) Installation of a replacement fin spar approved by the Manger, Rotorcraft Standards Staff, constitutes a terminating action for the requirements of this AD.
(b) For Model 205A and 205A-1 helicopters:
(1) Within 8 hours TIS, modify the vertical fin and visually inspect the fin spar for cracks in accordance with Part I (A1), paragraphs 1 through 5 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(i) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(ii) After inspection, apply MIL-PRF-81352 TYI clear lacquer or equivalent to the inside of the two lower rivet holes and on the surface where paint and primer were removed. Spray, brush, or wipe on a protective coat of MIL-C-16173, Grade 2, or equivalent, over the clear lacquer. To facilitate subsequent inspections do not replace the two lower rivets. See figure 2 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(iii) Before drilling or reaming, inspect all holes in the spar cap where rivets were removed for short edge distance. An existing edge distance less than 1.5 times the diameter of the drill or reamed hole must have FAA approval of the reworked area before proceeding.
(iv) Fasten the forward left-hand fin skin and the retainer, P/N 205- 032-851-045, to the fin spar assembly using Hi-Loks and blind rivets as specified in Figure 2 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998. Reinstall clip and radius block (if existing) removed in paragraph 2 of Part 1 (A1) of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(v) Refinish the reworked area.
(2) After initial modification and inspection of the vertical fin, thereafter, inspect the fin spar for cracks at intervals not to exceed 8 hours TIS as follows:
(i) Accomplish Part I (A2), paragraphs 1 through 3 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(ii) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(iii) After inspection, accomplish Part I (A2), paragraphs 5 and 6, of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(3) Within 25 hours TIS, modify and inspect the vertical fin as follows:
(i) Accomplish Part I (C1), paragraph 1 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(ii) Remove the clip, P/N 212-030-099-091, and radius block, P/N 212-030-099-095, if present. Remove theretainer, P/N 205-032-851-045, and sufficient rivets from the bottom row of the forward left-hand fin skin to allow trimming of the forward left-hand fin skin along the "skin cutline", at approximately Fin Station 66.31 (see Figure 2 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998).
(iii) Before drilling or reaming, inspect all holes in the spar cap where rivets were removed for short edge distance. An existing edge distance less than 1.5 times the diameter of the drill or reamed hole must have FAA approval of the reworked area before proceeding.
(iv) Accomplish Part I (C1), paragraphs 3, 4, and 6 in BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(v) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(vi) Accomplish Part I (C1) paragraphs 10 through 14 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(4) After the initial modification and dye-penetrant inspection of the fin spar, thereafter, at intervals not to exceed 300 hours TIS, inspect the fin spar as follows:
(i) Accomplish Part I (C2), paragraphs 1, 2, 3, 4, 5, and 7 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(ii) If a crack is discovered on the spar, replace the fin spar assembly with an airworthy fin spar assembly before further flight. Repair any corrosion or disbonding discovered during the inspection before further flight.
(iii) Accomplish Part I (C2), paragraphs 11 through 14 of ASB 205- 98-71, Revision A, dated September 21, 1998.
(5) Within 25 hours TIS, and thereafter at intervals not to exceed 300 hours TIS inspect the fin spar as follows:
(i) Accomplish Part I (B), paragraphs 1 through 13 of BHTI ASB 205-98-71, Revision A, dated September 21, 1998.
(ii) Repair any disbonding discovered during the inspection before further flight.
(6) Within 12 calendar months, remove fin spar, P/N 205-030-899-001, or - 089, or P/N 205-030-846-087, or -089, or P/N 205-032-851-003, -007, or -009. Replace it with an airworthy fin spar configuration that has been demonstrated to the FAA to satisfy the structural fatigue requirements of repeated high torque events and is approved by the Manager, Rotorcraft Standards Staff, or replace it with fin spar assembly, P/N 205-530-514-103, as specified in BHTI ASB 205-98-73, dated September 25, 1998.
(7) Installing fin spar, P/N 205-530-514-103, or a fin spar that has been approved by the Manager, Rotorcraft Standards Staff, constitutes terminating action for the requirements of this AD.
(c) 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 Certification Office. Operators shall submit their requests through a FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Certification Office.
NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Certification Office.
(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished.
(e) The inspections and modifications shall be done in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin 204B-98-50, dated October 22, 1998; 205-98-71, Revision A, dated September 21, 1998; or 205-98-73, dated September 25, 1998, as applicable. These incorporations by reference were 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 Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101, telephone (817) 280-3391, fax (817) 280-6466. 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.
(f) This amendment becomes effective on September 16, 1999.