[Federal Register Volume 61, Number 221 (Thursday, November 14, 1996)]
[Proposed Rules]
[Pages 58356-58358]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-29104]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-SW-25-AD]


Airworthiness Directives; Bell Helicopter Textron, Inc. Model 
214ST 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

[[Page 58357]]

directive (AD), applicable to Bell Helicopter Textron, Inc. (BHTI) 
Model 214ST helicopters, that currently establishes a mandatory 
retirement life of 50,000 high-power events for the main rotor mast 
(mast). This action would require changing the retirement life for the 
mast from high-power events to a maximum accumulated Retirement Index 
Number (RIN) of 140,000 and apply this RIN to an additional part 
numbered mast. This proposal is prompted by fatigue analyses and tests 
that show certain masts fail sooner than originally anticipated because 
of an unanticipated high number of takeoffs and external load lifts in 
addition to the deterioration in strength that occurs under other 
operating conditions. The actions specified by the proposed AD are 
intended to prevent fatigue failure of the mast, which could result in 
failure of the main rotor system and subsequent loss of control of the 
helicopter.

DATES: Comments must be received by January 13, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 94-SW-25-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 Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, 
Texas 76101.

FOR FURTHER INFORMATION CONTACT: Mr. Uday Garadi, Aerospace Engineer, 
FAA, Rotorcraft Certification Office, Rotorcraft Directorate, Fort 
Worth, Texas 76193-0170, telephone (817) 222-5157, fax (817) 222-5959.

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. 94-SW-25-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. 94-SW-25-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 
76137.

Discussion

    On July 13, 1994, the FAA issued AD 94-15-04, Amendment 39-8975, 
(59 FR 37155, July 21, 1994), to require changing the method of 
calculating the retirement life for the mast, part number (P/N) 214-
040-090-109, from flight hours to high-power events calculated using 
the number of takeoffs and external load lifts (torque events). That 
action was prompted by fatigue analysis and retesting that showed 
certain masts fail sooner than originally anticipated because of an 
unanticipated high number of takeoffs and external load lifts performed 
with those masts in addition to the anticipated deterioration in 
strength that occurs under other operating conditions. The requirements 
of that AD are intended to prevent fatigue failure of the mast, which 
could result in failure of the main rotor system and subsequent loss of 
control of the helicopter.
    Since the issuance of that AD, BHTI has issued BHTI Information 
Letter GEN-94-54, dated April 15, 1994, Subject: Retirement Index 
Number (RIN) For Cycle Lifed Components, which introduces a different 
method of accounting for fatigue damage on components that have 
shortened service lives as a result of frequent torque events. 
Additionally, BHTI has issued BHTI Alert Service Bulletin (ASB) 214ST-
94-67, dated November 7, 1994, which is applicable to Model 214ST 
helicopters, which describes procedures for creation of a component 
history card within the next 25 hours time-in-service (TIS) for the 
Model 214ST helicopters. The ASB also describes an alternate retirement 
life of a maximum RIN count of 140,000 for the Model 214ST mast. 
Finally, the ASB includes an additional P/N for the main rotor mast 
which was not included in the existing AD.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other BHTI Model 214ST helicopters of the same type 
design, the proposed AD would supersede AD 94-15-04 to require creation 
of a component history card using RIN counts, and establish a 
retirement life of a maximum accumulated RIN for the masts of 140,000.
    The FAA estimates that nine helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately (1) 48 
work hours per helicopter to replace the mast; (2) 2 work hours per 
helicopter to create the component history card or equivalent record 
(record); and (3) 10 work hours per helicopter to maintain the record 
each year, and that the average labor rate is $60 per work hour. 
Required parts would cost approximately $17,267 per mast. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $36,700 for the first year and $35,800 for 
each subsequent year. These costs assume replacement of the mast in 
one-sixth of the fleet each year, creation and maintenance of the 
records for all the fleet the first year, and creation of one-sixth of 
the fleet's records and maintenance of the records for all the fleet 
each subsequent year.
    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.

[[Page 58358]]

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 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-8975 (59 FR 
37155, July 21, 1994), and by adding a new airworthiness directive 
(AD), to read as follows:

Bell Helicopter Textron, Inc. (BHTI): Docket No. 94-SW-25AD. 
Supersedes AD 94-15-04, Amendment 39-8975.

    Applicability: Model 214ST helicopter with main rotor mast 
(mast), part number (P/N) 214-040-090-109 or P/N 214-040-090-121, 
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 (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 within 25 hours time-in-service (TIS) after 
the effective date of this AD, unless accomplished previously.
    To prevent fatigue failure of the mast, which could result in 
failure of the main rotor system and subsequent loss of control of 
the helicopter, accomplish the following:
    (a) Create a component history card or an equivalent record for 
the affected mast.
    (b) Determine and record the accumulated Retirement Index Number 
(RIN) to date on the mast as follows:
    (1) For operators with mast, P/N 214-040-090-109, multiply the 
takeoffs and external load lifts (high-power events) total to date 
by 2.8 (round up the result to the next whole number).
    (2) For operators with mast, P/N 214-040-090-121, multiply the 
factored flight hour total to date by 14 (round up the result to the 
next whole number).
    (3) Record on the component history card the accumulated RIN.

    Note 2: BHTI Alert Service Bulletin (ASB) No. 214ST-94-67, dated 
November 7, 1994, pertains to this subject.

    (c) After complying with paragraphs (a) and (b) of this AD, 
during each operation thereafter, maintain a count of the number and 
type of external load lifts and the number of takeoffs performed, 
and at the end of each day's operations, increase the accumulated 
RIN on the component history card as follows:
    (1) Increase the RIN by 2 for each takeoff.
    (2) Increase the RIN by 2 for each external load lift operation; 
or, increase the RIN by 4 for each external load lift operation in 
which the load is picked up at a higher elevation and released at a 
lower elevation, and the difference in elevation between the pickup 
point and the release point is 200 feet or greater.
    (d) Remove the mast, P/N 214-040-090-109 or -121, from service 
on or before attaining an accumulated RIN of 140,000. The mast is no 
longer retired based upon flight hours. This AD revises the 
Airworthiness Limitations Section of the maintenance manual by 
establishing a new retirement life for the mast of 140,000 RIN.
    (e) 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, 
FAA, 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.

    (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 November 5, 1996.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-29104 Filed 11-13-96; 8:45 am]
BILLING CODE 4910-13-U