[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
