AD 96-18-15

Active

Tail Rotor Blade

Key Information
96-18-15
Active
September 23, 1996
Not specified
96-SW-08-AD
39-9740
Applicability
["Aircraft"]
["Rotorcraft"]
Bell Helicopter Textron, A Division of Textron Canada
222 222B 222U 230
Summary

This amendment supersedes an existing airworthiness directive (AD) 96-01-08, which superseded Priority Letter AD 95-23-02, both of which were applicable to certain serial-numbered Bell Helicopter Textron, A Division of Textron Canada Ltd. (BHT) Model 222, 222B, 222U, and 230 helicopters, that currently requires an initial check of both surfaces of each tail rotor blade (blade) for cracks; an inspection of the blade skin if a crack of a specified size or location is found in the paint; and replacement of the blade if a crack is found in the blade skin. This AD requires the same actions as required by the existing AD, but expands the applicability to include additional blade part numbers (P/N). This amendment is prompted by three incidents in which a crack developed in the stainless steel blade skins due to sanding marks on the blades that occurred during the manufacturing process on BHT Model 230 helicopters, which are similar in design to the Model 222, 222B and 222U helicopters. The actions specified by this AD are intended to prevent failure of a blade due to a fatigue crack, loss of the tail rotor and tail rotor gear box, and subsequent loss of control of the helicopter.

Action Required

Final rule; request for comments

Regulatory Text

96-18-15 BELL HELICOPTER TEXTRON, A DIVISION OF TEXTRON CANADA LTD.: Amendment 39-9740. Docket No. 96-SW-08-AD. Supersedes AD 96-01-08, issued December 21, 1995, Docket No. 95-SW-33-AD, which supersedes Priority Letter 95-23-02. \n\n\tApplicability: Model 222 helicopters, serial numbers (S/N) 47006 through 47089, and Model 222B helicopters, S/N 47131 through 47156, with tail rotor blades, part numbers (P/N) 222-016-001-101, -107, -111, -113, -115, and -119; Model 222U helicopters, S/N 47501 through 47574, with tail rotor blades, P/N 222-016-001-107, -111, and -115; and Model 230 helicopters, S/N 23001 through 23038, with tail rotor blades, P/N 222-016-001-111 and -115, 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 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 (g) 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. \n\n\tCompliance: Required before further flight, unless accomplished previously. \n\n\tTo prevent failure of a tail rotor blade (blade) due to a fatigue crack (see Figure 1), loss of the tail rotor and tail rotor gear box, and subsequent loss of control of the helicopter, accomplish the following: \n\n\t(a)\tClean the painted surfaces of the blades in an area approximately 6 inches spanwise on either side of the doubler tip. Visually check both surfaces of each blade for cracks by pushing the blade tip away from the surface being checked until it contacts the flapping stop and then holding the blade firmly against the stop. Pay particular attention to the area reaching from the doubler tip to 1 inch outboard, centering on an area 2 inches aft of the blade leading edge (see Figure 2). \n\n\t(b)\tThe visual check required by paragraph (a) may be performed by an owner/operator (pilot) holding at least a private pilot certificate, and must be entered into the aircraft records showing compliance with paragraph (a) of this AD in accordance with sections 43.11 and 91.417(a)(2)(v) of the Federal Aviation Regulations (14 CFR sections 43.11 and 91.417(a)(2)(v)). \n\n\t(c)\tIf the visual check described in paragraph (a) reveals any crack outboard of the doubler tip (Station 14.250), or any chordwise crack inboard of the doubler tip that is longer than 1 inch (see Figure 3), accomplish the following: \n\n\t\t(1)\tRemove the paint from the skin in the cracked area using the following procedures (see Figure 4): \n\n\tNOTE 2: Paint cracking that follows the contour of the doubler is common and requires no action. \n\n\t\t(2)\tUsing a 180 or 220 grit abrasion paper, sand by hand with spanwise strokes until greenish- or yellow-colored primer or bare metal begins to be exposed. \n\n\t\t(3)\tUsing spanwise or circular sanding motions, continue hand-sanding the remaining greenish- or yellow-colored primer in the cracked area using a 320 or 400 grit paper until sufficient metal has been exposed to allow inspection (see area indicated in Figure 4). \n\n\t(d)\tInspect the blade skin for cracks in the area that was exposed in accordance with paragraph (c) using a 10-power or higher magnifying glass. \n\n\t\t(1)\tIf no crack is found in the blade skin, coat the bare metal area with a light-weight oil or an equivalent corrosion preventive compound. \n\n\t\t(2)\tIf any crack is discovered, remove the blade and replace it with an airworthy blade. \n\n\t(e)\tPerform the requirements of this AD upon installation of a replacement blade. \n\n\t(f)\tPerform the visual checks of paragraph (a) of this AD and the subsequent inspections, if appropriate, at intervals not to exceed 3 hours TIS. \n\n\tNOTE 3: A light-weight oil or equivalent corrosion preventive compound may be applied after accomplishing the repetitive requirements of paragraph (f) of this AD. \n\n\t(g)\tAn 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, Rotorcraft Directorate, 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 4: 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)\tSpecial flight permits to accomplish the requirements of this AD will not be issued. \n\n\t(i)\tThis amendment becomes effective on September 23, 1996.

Supplementary Information

On November 3, 1995, the FAA issued priority letter AD 95-23-02, applicable to certain serial-numbered BHT Model 222, 222B, 222U, and 230 helicopters, to require an initial check of both surfaces of each blade for cracks; an inspection of the blade skin if a crack of a specified size or location was found in the paint; and replacement of the blade if a crack was found in the blade skin. That action was prompted by two incidents in which a crack developed in the stainless steel blade skins on BHT Model 230 helicopters. In one of these incidents, the blade failed during flight. Subsequent investigation revealed fatigue cracks originating from sanding marks on the blade skin. The cracks were located just outboard of the stainless steel blade doubler. That condition, if not corrected, could result in failure of a blade due to a fatigue crack, loss of the tail rotor and tail rotor gear box, and subsequent loss of control of the helicopter. Subsequent to the issuance of the priority letter AD, the FAA issued AD 96-01-08 to publish the priority letter in the Federal Register and to correct an error in the applicability paragraph of the priority letter AD, which incorrectly stated the serial number (S/N) of one of the affected models. The Model 230 helicopters affected by the AD include S/N 23001 through 23038. The priority letter AD incorrectly stated S/N 23001 through 23034. \n\n Since the issuance of AD 96-01-08, a crack has been discovered in the tail rotor blade of another serial-numbered Model 230 helicopter, that originated from a small indentation that occurred during the manufacturing process. As a result of this discovery, additional part-numbered blades have been determined to be affected.\n\n Since the unsafe condition described is likely to exist or develop on other BHT Model 222, 222B, 222U, and 230 helicopters of the same type design, this AD supersedes AD 96-01-08 to require, before further flight, an initial visual check of both painted surfaces of each blade for cracks. If a crack of a specified size and location is found in the paint, removal of the paint and a visual inspection using a 10-power or higher magnifying glass is required before further flight. If this closer inspection reveals a crack in the blade skin, replacement of the blade with an airworthy blade is required. If no crack is found in the blade skin, the area from which the paint was removed is coated with a light-weight oil or an equivalent corrosion preventive compound, and then repetitive visual checks are required at intervals not to exceed 3 hours time-in-service (TIS). The initial visual check that is required before further flight and the repetitive checks may be performed by a pilot, but must be entered into the aircraft records showing compliance with paragraph (a) of this AD in accordance with sections 43.11 and 91.417 (a)(2)(v) of the Federal Aviation Regulations (14 CFR sections 43.11 and 91.417 (a)(2)(v)). This AD allows a pilot to perform this check because it involves only a visual check for cracking in the painted surface of the blade skin, and can be performed equally well by a pilot or a mechanic.\n\n Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.\n\nComments Invited\n Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications receivedon or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.\n\n Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.\n \n Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 96-SW-08-AD." The postcard will be date stamped and returned to the commenter.\n\n The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \n\n The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."\n\nList of Subjects in 14 CFR Part 39 \n Air transportation, Aircraft, Aviation safety, Safety.\n\nAdoption of the Amendment\n Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:\n\nPART 39 - AIRWORTHINESS DIRECTIVES \n 1. The authority citation for part 39 continues to read as follows: \n Authority: 49 USC 106(g), 40113, 44701.\n\n§ 39.13 - (Amended)\n 2. Section 39.13 is amended by adding the following new airworthiness directive (AD), Amendment 39-9740, to read as follows:

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Contact Information

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Assistant Chief Counsel, Attention: Rules Docket No. 96-SW-08-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. \nFOR FURTHER INFORMATION CONTACT: Mr. Charles Harrison, Aerospace Engineer, Rotorcraft Certification Office, Rotorcraft Directorate, FAA, Fort Worth, Texas 76193-0170, telephone (817) 222-5447, fax (817) 222-5960.

References
This information is not available.
--- - Part 39 )61 FR 47041 NO. 174 09/06/96)
FAA Documents