Airworthiness Directives; Bell Helicopter Textron, Inc. Manufactured Model AH-1, HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH- 1F, UH-1H, UH-1L, and UH-1P Helicopters

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 96-SW-11-AD; Amendment 39-9741; AD 96-12-26 ]

RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron, Inc.

Manufactured Model AH-1, HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-

1F, UH-1H, UH-1L, and UH-1P Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: This document publishes in the Federal Register an amendment

adopting Airworthiness Directive (AD) AD 96-12-26 which was sent

previously to all known U.S. owners and operators of Bell Helicopter

Textron, Inc. (BHTI) manufactured Model AH-1, HH-1K, TH-1F, TH-1L, UH-

1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P 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.

[[Page 47048]]

DATES: Effective September 23, 1996, to all persons except those

persons to whom it was made immediately effective by priority letter AD

96-12-26 issued on June 5, 1996, which contained the requirements of

this amendment.

Comments for inclusion in the Rules Docket must be received on or

before November 5, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Office of the Assistant Chief Counsel, Attention:

Rules Docket No. 96-SW-11-AD, 2601 Meacham Blvd., Room 663, Fort Worth,

Texas 76137.

The applicable service information may be obtained from Bell

Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101.

FOR FURTHER INFORMATION CONTACT: Mr. Charles Harrison, Aerospace

Engineer, Rotorcraft Certification Office, 2601 Meacham Blvd., Fort

Worth, Texas 76137, telephone (817) 222-5447, fax (817) 222-5960.

SUPPLEMENTARY INFORMATION: On June 5, 1996, the FAA issued priority

letter AD 96-12-26, applicable to BHTI-manufactured Model AH-1, HH-1K,

TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P

helicopters, 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 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-manufactured Model AH-1, HH-1K, TH-1F, TH-1L, UH-1A, UH-

1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters of the same type

design, the FAA issued priority letter AD 96-12-26, to inspect for

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 the each T/R blade

for peeling, flaking, or bubbling paint that may indicate corrosion, 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-

manufactured Model AH-1, HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-

1F, UH-1H, UH-1L, and UH-1P 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. 96SW-11-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.

[[Page 47049]]

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding a new airworthiness directive

to read as follows:

AD 96-12-26 California Department of Forestry; Erickson Air Crane

Co.; Garlick Helicopters; Hawkins and Powers Aviation, Inc.;

International Helicopters, inc.; Smith Helicopters; Southwest

Florida Aviation; West Coast Fabrications; Western International

Aviation, Inc.; Williams Helicopter Technology, Inc.; and UNC

Helicopters: Amendment 39-9741. Docket No. 96-SW-11-AD.

Applicability: Bell Helicopter Textron, Inc.manufactured Model

AH-1, HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L,

and UH-1P helicopters, with tail rotor (T/R) blade (blade), part

number (P/N) 204-011-702-015 or -121, serial numbers (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 remove soot 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. 204-9648, Revision

A, dated February 12, 1996, which pertains to Model 204B

helicopters, also pertains to this AD.

(d) 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,

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 96-12-26, issued June 5, 1996, which

contained the requirements of this amendment.

Issued in Fort Worth, Texas, on August 26, 1996.

Daniel P. Salvano,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 96-22573 Filed 9-5-96; 8:45 am]

BILLING CODE 4910-13-U