[Federal Register Volume 61, Number 94 (Tuesday, May 14, 1996)]
[Rules and Regulations]
[Pages 24218-24220]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-11958]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-SW-01-AD; Amendment 39-9616; AD 96-06-12]
RIN 2120-AA64


Airworthiness Directives; Bell Helicopter Textron, Inc. Model 
47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 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 47-K Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 96-06-12 which was sent 
previously to all known U.S. owners and operators of Bell Helicopter 
Textron, Inc. (Bell) Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 
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 47-K helicopters by 
individual letters. This AD requires a visual inspection of each tail 
rotor blade (blade) tip, abrasion strip, blade skin, and blade butt for 
corrosion or delamination. This amendment is prompted by reports that a 
number of Model 47 helicopter blades were manufactured using a clad 
aluminum alloy material instead of a bare aluminum alloy material. The 
actions specified by this AD are intended to prevent premature 
delamination or separation of the blade tip block or the abrasion 
strip, which could lead to failure of the blade and subsequent loss of 
control of the helicopter.


[[Page 24219]]


DATES: Effective May 29, 1996, to all persons except those persons to 
whom it was made immediately effective by priority letter AD 96-06-12, 
issued on March 13, 1996, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before July 15, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 96-SW-01-AD, 2601 Meacham Blvd., Room 663, Fort Worth, 
Texas 76137.

FOR FURTHER INFORMATION CONTACT: Mr. Tony Nguyen, Aerospace Engineer, 
Rotorcraft Certification Office, Rotorcraft Directorate, FAA, 2601 
Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5177; fax 
(817) 222-5960.

SUPPLEMENTARY INFORMATION: On March 13, 1996, the FAA issued priority 
letter AD 96-06-12, applicable to Bell Model 47B, 47B-3, 47D, 47D-1, 
47G, 47G-2, 47G-2A, 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 47-
K helicopters, which requires, prior to the first flight of each day, 
and at intervals not to exceed 10 hours time-in-service (TIS) if the 
helicopter is operated for more than 10 hours in any one day, a visual 
inspection of each blade tip, abrasion strip, blade skin, and blade 
butt for corrosion or delamination. That action was prompted by reports 
that a number of Model 47 helicopter blades were manufactured using a 
clad aluminum alloy material instead of a bare aluminum alloy material. 
The shear and peel strength of bonded clad aluminum alloy is less than 
the shear and peel strength of bonded bare aluminum alloy. This 
condition, if not corrected, could result in premature delamination or 
separation of the blade tip block or the abrasion strip, which could 
lead to failure of the blade and subsequent loss of control of the 
helicopter.
    Since the unsafe condition described is likely to exist or develop 
on other Bell Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 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 47-K helicopters of the same 
type design, the FAA issued priority letter AD 96-06-12 to prevent 
premature delamination or separation of the blade tip block or the 
abrasion strip, which could lead to failure of the blade and subsequent 
loss of control of the helicopter. The AD requires, prior to the first 
flight of each day, and at intervals not to exceed 10 hours TIS, if the 
helicopter is operated for more than 10 hours in any one day, a visual 
inspection of each blade tip, abrasion strip, blade skin, and blade 
butt for corrosion or delamination. If any of the inspections reveal 
corrosion or delamination, removal of the blades and replacement with 
airworthy blades is required.
    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 March 13, 1996 to all known U.S. owners and operators of Bell 
Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 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 47-K 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-01-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 U.S.C. 106(g), 40113, 44701.

[[Page 24220]]

Sec. 39.13  [Amended]

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

AD 96-06-12  Bell Helicopter Textron, Inc.: Amendment 39-9616. 
Docket No. 96-SW-01-AD.

    Applicability: Model 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, 47G-2A, 
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 47-K helicopters, 
with tail rotor blade assembly, part number (P/N) 047-642-117-105, 
serial numbers (S/N) A-1943 through A-2068, 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 (f) 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 premature delamination or separation of the tail 
rotor blade (blade) tip block or the abrasion strip, which could 
lead to failure of the blade and subsequent loss of control of the 
helicopter, accomplish the following:
    (a) Prior to the first flight of each day, visually inspect each 
blade tip, abrasion strip, blade skin and blade butt as follows:
    (1) Inspect each blade tip for corrosion or delamination 
adjacent to the abrasion strip and tip block.
    (2) Inspect each abrasion strip for corrosion or delamination, 
paying particular attention to the abrasion strip leading edge.
    (3) Inspect each blade skin for corrosion, paying particular 
attention to any areas of paint cracking or damage. Inspect all 
bonded joints for corrosion or delamination.
    (4) Inspect each blade butt around the bearings for corrosion or 
delamination.
    (b) Thereafter, conduct the visual inspections specified in 
paragraph (a) of this AD at intervals not to exceed 10 hours time-
in-service.
    (c) If the inspections required by paragraphs (a) and (b) of 
this AD reveal any corrosion or delamination, replace the blade with 
an airworthy blade before further flight.
    (d) Installation of any airworthy tail rotor blade assembly 
which has been FAA-approved for the particular Model 47 helicopter, 
except for P/N 047-642-117-105 with S/N A-1943 through A-2068, 
constitutes a terminating action for the requirements of this AD.
    (e) Installation of tail rotor blade assembly, P/N 047-642-117-
105M, including those with S/N A-1943 through A-2068, constitutes a 
terminating action for the requirements of this AD.

    Note 2: Bell Helicopter Textron Alert Service Bulletin No. 47-
96-21, dated January 29, 1996, pertains to this AD.

    (f) 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. 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.

    (g) 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.
    (h) This amendment becomes effective on May 29, 1996, to all 
persons except those persons to whom it was made immediately 
effective by Priority Letter AD 96-06-12, issued March 13, 1996, 
which contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on May 3, 1996.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-11958 Filed 5-13-96; 8:45 am]
BILLING CODE 4910-13-U