[Federal Register Volume 62, Number 4 (Tuesday, January 7, 1997)]
[Proposed Rules]
[Pages 951-953]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-251]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-SW-32-AD]


Airworthiness Directives; Hiller Aircraft Corporation Model UH-
12A, UH-12B, UH-12C, UH-12D, and UH-12E Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to Hiller Aircraft Corporation 
(Hiller) Model UH-12A, UH-12B, UH-12C, UH-12D, and UH-12E helicopters, 
that currently requires a dye penetrant inspection of the head of the 
main rotor outboard tension-torsion (T-T) bar pin for cracks; a visual 
inspection of the outboard T-T bar pin for proper alignment and an 
adjustment, if necessary; and, installation of shims at the inboard end 
of the drag strut. This action would require the same actions required 
by the existing AD, but would allow a magnetic particle inspection of 
the T-T bar pin as an alternative to the currently required dye 
penetrant inspection, and would require reporting the results of the 
inspections only if cracks are found, rather than reporting all results 
of inspections as required by the existing AD. This proposal is 
prompted by an FAA analysis of a comment to the existing AD, and the 
fact that no cracks have been reported since the issuance of the 
existing AD. The actions specified by the proposed AD are intended to 
prevent cracks in the head area of the outboard T-T bar pin, which 
could result in loss of in-plane stability of the main rotor blade and 
subsequent loss of control of the helicopter.

DATES: Comments must be received by March 10, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 96-SW-32-AD, 2601 Meacham Blvd., Room 663, Fort Worth, 
Texas 76137. Comments may be inspected at this location between 9:00 
a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Hiller Aircraft Corporation, 3200 Imjin Road, Marina, 
California 93933-5101. This information may be examined at the FAA, 
Office of the Assistant Chief Counsel, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas.

FOR FURTHER INFORMATION CONTACT: Mr. Charles Matheis, Aerospace 
Engineer, FAA, Los Angeles Aircraft Certification Office, 3960 
Paramount Blvd., Lakewood, California 90712-4137, telephone (310) 627-
5235, fax (310) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 96-SW32-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Office of the Assistant Chief Counsel, Attention: Rules 
Docket No. 96-SW-32-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 
76137.

Discussion

    On May 25, 1995, the FAA issued AD 95-12-02, Amendment 39-9252 (60 
FR 30184) to require for Hiller Model UH-12A, UH-12B, UH-12C, UH-12D, 
and UH-12E helicopters, within 25 hours time-in-service (TIS) or at the 
next 100 hour inspection, whichever occurs first, and thereafter at 
intervals not to exceed 100 hours TIS: (1) an inspection of the 
alignment of the outboard T-T bar pin and an adjustment, if necessary; 
and (2) an inspection for cracks in the head of the outboard T-T bar 
pin using a dye

[[Page 952]]

penetrant method. Additionally, that AD requires, within 25 hours TIS 
or at the next 100 hour inspection, whichever occurs first, the 
installation of shims between the inboard end of the drag strut and the 
outboard T-T bar pin. That action was prompted by two accidents 
involving failure of the outboard T-T bar pin on Hiller UH-12E 
helicopters. The requirements of that AD are intended to prevent cracks 
in the head area of the outboard T-T bar pin, which could result in 
loss of in-plane stability of the main rotor blade and subsequent loss 
of control of the helicopter.
    Since the issuance of that AD, the FAA has received a comment 
suggesting that paragraph (b) of the existing AD should specifically 
identify the compliance time for the inspection, even though the 
compliance time is stated in paragraph (a). The FAA agrees with the 
commenter, and the wording of paragraph (b) has been changed to clarify 
the inspection compliance time. Additionally, the same commenter 
requested that an alternate method of compliance for the inspection be 
included in paragraph (b) of the existing AD. The FAA agrees, and 
paragraph (b) has been changed to allow the use of a magnetic particle 
inspection as well as a dye penetrant inspection required by the 
existing AD. One additional commenter states that misalignment of the 
drag strut fork and the main rotor blade may be causing cracks. While 
the cause of the cracks is uncertain, the FAA has determined that the 
recurring inspections required by this AD should detect misalignments 
and cracks that could lead to failure of the T-T bar pin.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Hiller Model UH-12A, UH12B, UH-12C, UH-12D, 
and UH-12E helicopters of the same type design, the proposed AD would 
supersede AD 95-12-02 to require, within 25 hours TIS or at the next 
100 hour inspection, whichever occurs first, and thereafter at 
intervals not to exceed 100 hours TIS: (1) an inspection of the 
alignment of the outboard T-T bar pin and an adjustment, if necessary; 
and (2) an inspection for cracks in the head of the outboard T-T bar 
pin using a dye penetrant method or a magnetic particle method. 
Additionally, the proposed AD requires, within 25 hours TIS or at the 
next 100 hour inspection, whichever occurs first, the installation of 
shims between the inboard end of the drag strut and the outboard T-T 
bar pin.
    The FAA estimates that 700 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 2 work 
hours per helicopter to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $700 per pin. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be 
$574,000, assuming one pin must be replaced on every helicopter in the 
fleet.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-9252 (60 FR 
30184, June 8, 1995), and by adding a new airworthiness directive (AD), 
to read as follows:

Hiller Aircraft Corporation: Docket No. 96-SW-32-AD. Supersedes AD 
95-12-02, Amendment 39-9252.

    Applicability: Model UH-12A, UH-12B, UH-12C, UH-12D, and UH-12E 
helicopters, 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 (e) 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 cracks in the head area of the outboard tension-
torsion (T-T) bar pin, which could result in loss of in-plane 
stability of the main rotor blade and subsequent loss of control of 
the helicopter, accomplish the following:
    (a) Within 25 hours time-in-service (TIS) after the effective 
date of this AD, or at the next 100 hour inspection, whichever 
occurs first, and thereafter at intervals not to exceed 100 hours 
TIS, inspect the alignment of the outboard T-T bar pin, part number 
(P/N) 51452, and adjust the alignment, if necessary, in accordance 
with Hiller Aviation Service Letter (SL) 51-2, dated March 31, 1978.
    (b) Within 25 hours TIS after the effective date of this AD, or 
at the next 100 hour inspection, whichever occurs first, and 
thereafter at intervals not to exceed 100 hours TIS, inspect the 
head of the outboard T-T bar pin for cracks using a dye penetrant or 
magnetic particle inspection method.
    (c) If a crack is found as a result of the inspection required 
by paragraph (b) of this AD, report the results within 7 working 
days following the inspection to the Manager, Los Angeles Aircraft 
Certification Office, Attention Charles Matheis, ANM-120L, 3960 
Paramount Blvd., Lakewood, California 90712-4137. Include the 
helicopter model number, serial number, and total TIS of the 
outboard T-T bar pin in the report. Reporting requirements have been 
approved by the Office of Management and Budget and assigned OMB 
control number 2120-0056.
    (d) Within 25 hours TIS after the effective date of this AD, or 
at the next 100 hours TIS inspection, whichever occurs first, 
install shims between the inboard end of the drag strut and the 
outboard T-T bar pin in accordance with the Accomplishment 
Instructions of Hiller Aviation Service Bulletin No. 51-9, dated 
April 8, 1983.
    (e) An alternative method of compliance or adjustment of the 
compliance time that

[[Page 953]]

provides an acceptable level of safety may be used if approved by 
the Manager, Los Angeles Aircraft 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, Los Angeles Aircraft Certification Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles Aircraft Certification Office.

    (f) 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. Issued in Fort 
Worth, Texas, on December 30, 1996.
Larry M. Kelly,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 97-251 Filed 1-6-97; 8:45 am]
BILLING CODE 4910-13-U