AD 96-12-25

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) AD 96-12-25 which was sent previously to all known U.S. owners and operators of Bell Helicopter Textron, Inc. (BHTI) Model 204B helicopters by individual letters. This AD requires a visual inspection of each tail rotor (T/R) blade (blade) for peeling, flaking, or bubbling paint that may indicate corrosion; an inspection for corrosion, if necessary; and replacement of the T/R blade with an airworthy blade if corrosion is discovered. This amendment is prompted by an FAA determination, based on the manufacturer's data, that certain serial-numbered T/R blades were manufactured with internal leading edge doublers fabricated from clad aluminum instead of bare aluminum material. The actions specified by this AD are intended to prevent debonding of the main spar internal leading edge doubler, which could lead to failure of a T/R blade and subsequent loss of control of the helicopter.

Final rule; request for comments

96-12-25 BELL HELICOPTER TEXTRON, INC.: Amendment 39-9739. Docket No. 96- SW-07-AD.

Applicability: Model 204B helicopters, serial numbers (S/N) 2001 through 2070 and S/N 2196 through 2199, with tail rotor (T/R) blade (blade), part number (P/N) 204-011-702-015 or -121, S/N A-20262 through A-20268, A-20270 through A-20282, A-20284 through A-20287, A- 20289 through A-20422, A-20424 through A-20428, A-20430 through A-20433, A-20435 through A-20464, A-20466 through A-20497, A-20499 through A-21019, A-21027 through A- 21031, A-21041, A-21047, A-21049 and A-21059, 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 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 (d) 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent debonding of the main spar internal leading edge doubler, which could lead to failure of a T/R blade and subsequent loss of control of the helicopter, accomplish the following:

(a) Within 10 hours time-in-service (TIS) after the effective date of this AD, and thereafter at intervals of not more than 7 calendar days, clean each T/R blade using a mild detergent and water to removesoot and grime.

(b) Visually inspect each T/R blade for peeling, flaking, or bubbling paint, or corrosion along the bond lines viewed from the root and tip ends of the blade, and at the abrasion strip bond line on both sides of the blade from the root to the tip.

(c) If the visual inspection indicates peeling, flaking, or bubbling paint, remove the paint from the affected area and perform a visual inspection for corrosion.

(1) If no corrosion is noted, refinish the blade.
(2) If corrosion is noted in the bond lines of the affected areas, remove the blade and replace it with an airworthy blade. Replacement with an airworthy blade that has a serial number not listed in the Applicability section of this AD constitutes a terminating action for this AD.

NOTE 2: Bell Helicopter Textron, Inc. ASB No. 204-96-48, Revision A, dated February 12, 1996, pertains to this AD.

(d) An alternative method of compliance or adjustment of the compliance time that provides anacceptable 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.

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.

(e) 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.

(f) This amendment becomes effective on September 23, 1996, to all persons except those persons to whom it was made immediately effective by priority letter AD 96-12-25, issued June 5, 1996, which contained the requirements of this amendment.

On June 5, 1996, the FAA issued priority letter AD 96-12-25, applicable to BHTI Model 204B helicopters, serial numbers (S/N) 2001 through 2070 and S/N 2196 through 2199, which requires a visual inspection of each T/R blade for peeling, flaking, or bubbling paint that may indicate corrosion; an inspection for corrosion, if necessary; and, replacement of the T/R blade with an airworthy blade if corrosion is discovered. That action was prompted by an FAA determination, based on the manufacturer's data, that certain serial-numbered T/R blades were manufactured with internal leading edge doublers fabricated from clad aluminum instead of bare aluminum material. This condition, if not corrected, could result in debonding of the main spar internal leading edge doubler, which could lead to failure of a T/R blade and subsequent loss of control of the helicopter.

Since the unsafe condition described is likely to exist or develop on other BHTI Model 204B helicopters of the same type design, the FAA issued priority letter AD 96-12-25, to prevent debonding of the main spar internal leading edge doubler, which could lead to failure of a T/R blade and subsequent loss of control of the helicopter. The AD requires, within 10 hours time-in-service (TIS) after the effective date of this AD, and thereafter at intervals of not more than 7 calendar days, a visual inspection of each T/R blade for peeling, flaking, or bubbling paint, or corrosion along the bond lines viewed from the root and tip ends of the blade, and at the abrasion strip bond line on both sides of the blade from the root to the tip. If peeling, flaking, or bubbling paint is discovered, the paint in the affected area must be removed and the blade must be inspected for corrosion. If corrosion is discovered in the affected areas, the blade must be removed and replaced with an airworthy blade.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on June 5, 1996 to all known U.S. owners and operators of BHTI Model 204B helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.

Comments Invited
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 received on 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.

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.

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-07-AD." The postcard will be date stamped and returned to the commenter.

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.

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."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment
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:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 USC 106(g), 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: