2001-17-17: Main Rotor Blade Grip Threads

2001-17-17 Bell Helicopter Textron, Inc.: Amendment 39-12408. Docket No. 2001-SW-13-AD. Supersedes AD 2000-18-51, Amendment 39-11983, Docket No. 2000-SW-35-AD. \n\n\tApplicability: Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G2A, 47G-2A-1, 47G-3, 47G-3B, 47G-3B-1, 47G-3B-2, 47G-3B-2A, 47G-4, 47G-4A, 47G-5, 47G-5A, 47H-1, 47J, 47J-2, 47J-2A, and 47K helicopters, with main rotor blade grips, part number (P/N) 47-120-135-2, 47-120-135-3, 47-120-135-5, 47-120-252-1, 47-120-252-7, 47-120-252-11, 74-120-252-11, 74-120-135-5, R47-120-252-11, and R47-120-135-5, installed, certificated in any category. \n\n\tNote 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/operator must request approvalfor an alternative method of compliance in accordance with paragraph (g) 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. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent failure of a main rotor blade grip (grip), separation of a main rotor blade, and subsequent loss of control of the helicopter, accomplish the following: \n\n\t(a) Conduct an eddy current inspection of the threads of both grips for a crack in accordance with Appendix 1 of this AD or an equivalent FAA-approved procedure containing the requirements of the procedure in Appendix 1: \n\n\t\t(1) Within 300 hours time-in-service (TIS) since initial installation on any helicopter for a grip with less than 300 total hours TIS; \n\n\t\t(2) Within 10 hours TIS for a grip with 300 or more total hours TIS that has not had any previous dye penetrant or eddy current inspection; \n\n\t\t(3) Within 200 hours TIS since the last dye penetrant inspection; OR \n\n\t\t(4) Within 300 hours TIS since the last eddy current inspection, whichever occurs first. \n\n\t(b) Thereafter, conduct the eddy current inspection in accordance with Appendix 1 of this AD or an equivalent FAA-approved procedure containing the requirements of the procedure in Appendix 1 at intervals not to exceed 300 hours TIS. \n\n\t(c) Report the results of each inspection to the FAA Rotorcraft Certification Office within 7 calendar days. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056. \n\n\tNote 2: See Appendix 2 of this AD for a list of known eddy current inspection facilities. \n\n\t(d) If a crack is detected, before further flight, replace any cracked grip with an airworthy grip. \n\n\t(e) On or before 1200 hours TIS, replace each grip with an airworthy grip. \n\n\t(f) This AD establishes a retirement life of 1200 hours TIS for the grips, P/N 47-120-135-2, 47-120-135-3, 47-120-135-5, 47-120-252-1, 47-120-252-7, 47-120-252-11, 74-120-252-11, 74-120-135-5, R47-120-252-11, and R47-120-135-5. \n\n\t(g) 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, Rotorcraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Certification Office. \n\n\tNote 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Certification Office. \n\n\t(h) Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished. \n\n\t(i) This amendment becomes effective on October 3, 2001. \n\nAppendix 1 \n\nNondestructive Inspection Procedure \n\nTask: Eddy Current (ET) Inspection of Mast Threads for Cracks \n\n1.0 Area of Inspection \n\n\t1.1 The inboard inside diameter machined threads (reference figure 1). \n\n2.0 Equipment \n\n\t2.1 Zetec Miz-20/22, Phasec 2200 or equivalent piece of equipment. \n\n\t2.2 Match molded ET probe SPC-193 (100kHz) or equivalent. (See Figure 3.) \n\n\t2.3 Reference standard EC-010-021, or equivalent. (See Figures 4 and 5.) \n\n\t2.4 Light oil. \n\n3.0 Personnel Requirements \n\n\t3.1 Personnel performing the ET inspection must be minimally qualified to a Level II in ET inspection, certified in accordance with an industry accepted standard (such as ATA-105, NAS-410, or MIL-STD-410) or an FAA accepted company procedure. \n\n4.0 Standardization \n\n\t4.1 Connect probe to flaw detector and turn power on. \n\n\t4.2 Adjust the Phasec 2000 as shown in table 1. Adjust all other equipment as necessary. \n\n\t4.3 Adjust the V:H gain ratio to 1.5:1-2:1. \n\n\t4.4 Monitor the crack response when moving the probe in one direction only across each EDM notch of the standard. Adjust the coarse gain for a crack response of 2-3 units from the smallest (0.04") notch. Record the number units of displacement and noise level for each of the EDM notches. \n\n5.0 Pre Inspection \n\n\t5.1 The part shall be clean and free of loose debris. \n\n\t5.2 A thin coating of clean oil may be applied to the teeth to help the ET probe slide easily. \n\n6.0 Inspection \n\n\t6.1 Place the probe into the threaded area and slide it in the same direction as was done on the standard while monitoring the screen for root cracks. Moving the probe in the same direction produces a repeatable display that allows for more accurate flaw size determination. Scan the probe along each individual thread until all the threads are inspected. (See Figures 2 and 3.) \n\n7.0 Evaluation \n\n\t7.1 Repeatstandardization and rescan any areas where there is a vertical crack-like deflection. \n\n\t7.2 If indication persists, mark the location on the part. Record the number units of displacement, phase orientation, and noise level. \n\n8.0 Accept/Reject Criteria \n\n\t8.1 All repeatable crack-like indications above the noise level detected shall be cause for rejection. \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nAppendix 2 \n\nPartial List of Nondestructive Inspection Testing Facilities Identified by Operators and FAA \n\nMet Chem Testing Laboratories Inc. \n369 W. Gregson Ave. (3085 S.) \nSalt Lake City, Utah 84115-3440 \nPhone: (801) 487-0801 \nFAX: (801) 466-8790 http://frwebgate.access.gpo.gov/cgi-bin/leaving.cgi?from=leavingFR.html&log=linklog&to=http://www.metchemtesting.com \n\nGalactic NDT Services 10728 D. South Pipeline RD \nHurst, Texas 76053 \nPhone: (800) 458-6387 \n\nGlobal Testing Technologies \n1173 North Service Rd. Unit D3 \nOakville TorontoCanada \nPhone: (905) 847-9300 \nFAX: (905) 847-9330 \n\nParagon Services, Inc. \n1015 S. West St. \nWichita, KS 67213 \nPhone: (316) 945-5285 \nFAX: (316) 945-0629 \n\nNOE Services \n8775 E. Orchard Rd. #809 \nEnglewood, CO \nPhone: (303) 741-0518\nFAX: (303) 741-0519 \n\nApplied Technical Services, Inc. \n1190 Atlanta Industrial Drive \nMarietta, GA 30066 \nPhone: (770) 423-1400 \nFAX: (770) 514-3299 \n\nRotorcraft Support \nVan Nuys CA 91406 \nPhone: (818) 997-7667 \nFAX: (818) 997-1513 \n\nPalm Beach Aircraft Propeller, Inc \nPalm Beach County Park Airport \n2633 Lantana Road \nSuite 23, Bldg 1501 \nLantana, FL 33462 \nPhone: (800) 965-7767 \nFAX: (561) 965-7933 \nEmail: info@pbapi.com \nWebsite: http://frwebgate.access.gpo.gov/cgi- bin/leaving.cgi?from=leavingFR.html&log=linklog&to=http://www.\npbapi.com \nContact: Will Burbage \n\n\tOther FAA approved repair facilities may be used. \n\nAppendix 3 \n\nAD Compliance Inspection Report (Sample Format) \n\nBell Model 47 Main Rotor Blade Grip \n\n\tProvide the following information and mail or fax it to: \n\n\tManager, Rotorcraft Certification Office, \n\tFederal Aviation Administration, \n\tFort Worth, Texas, 76193-0170, USA, \n\tFax: 817-222-5783. \n\nAircraft Registration No: \nHelicopter Model: \nHelicopter Serial Number: \nOwner and Operator of the Helicopter: \n\n------------------------------------------------------------------------ \n\t\t\t\tGrip #1 Grip #2 \n------------------------------------------------------------------------ \nPart Number: \nSerial Number: \n------------------------------------------------------------------------ \n\nHours TIS on the Part at Inspection: \n\nCrack Found (Y/N) \nIf yes, describe below. \n\nDescription of Findings \n\nWho performed the inspections? \n\nIf a crack was found, describe the crack size, location, and orientation (provide a sketch or pictures with the grip part and serial number). \n\nProvide any other comments.