[Federal Register Volume 63, Number 128 (Monday, July 6, 1998)]
[Proposed Rules]
[Pages 36377-36379]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-17765]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 94-SW-23-AD]
Airworthiness Directives; Bell Helicopter Textron, Inc. Model
214B and 214B-1 Helicopters
ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening
of comment period.
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SUMMARY: This document revises an earlier proposed airworthiness
directive (AD), applicable to Bell Helicopter Textron, Inc. (BHTI)
Model 214B and 214B-1 helicopters, that would have established a
mandatory retirement life of 15,000 high-power events for the pillow
block bearing bolts (bearing bolts). That proposal was prompted by
fatigue analyses and tests that show certain bearing bolts fail sooner
than originally anticipated because of the unanticipated high number of
lifts and takeoffs (torque events) performed with those bearing bolts
in addition to the time-in-service (TIS) accrued under normal operating
conditions. This action revises the proposed rule by proposing the
creation of a component history card using a Retirement Index Number
(RIN) system, establishment of a system for tracking increases to the
accumulated RIN, and establishment of a maximum accumulated RIN for the
bearing bolts. The actions specified by this proposed AD are intended
to prevent fatigue failure of the bearing bolts, which could result in
failure of the main rotor system and subsequent loss of control of the
helicopter.
DATES: Comments must be received on or before September 4, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 94-SW-23-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137. Comments may be inspected at this location
[[Page 36378]]
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal
holidays.
FOR FURTHER INFORMATION CONTACT: Mr. Harry Edmiston, Aerospace
Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office,
Fort Worth, Texas 76193-0170, telephone (817) 222-5158, fax (817) 222-
5961.
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-23-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 Regional Counsel, Southwest Region,
Attention: Rules Docket No. 94-SW-23-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39), applicable to BHTI Model 214B and 214B-1 helicopters, was
published in the Federal Register on May 3, 1993 (58 FR 35902; July 2,
1993). That NPRM would have required changing the method of calculating
the retirement life for the bearing bolts, part number (P/N) 20-057-12-
48D and P/N 20-057-12-50D, from flight hours to equivalent operating
hours based on high-power events calculated using the number of
takeoffs and external load lifts, or a maximum of 15,000 high power
events, whichever occurred first. That NPRM was prompted by fatigue
analyses and tests that show certain bearing bolts fail sooner than
originally anticipated because of the unanticipated high number of
lifts and takeoffs (torque events) performed with those bearing bolts
in addition to the TIS accrued under normal operating conditions. That
condition, if not corrected, could result in fatigue failure of the
bearing bolts, which could result in failure of the main rotor system
and subsequent loss of control of the helicopter.
Since the issuance of that NPRM, 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) 214-94-
54, dated November 7, 1994, which describes procedures for converting
flight hours and total number of torque events into a RIN for the
bearing bolts, P/N 20-057-12-48D.
The FAA desires to implement a standardized system to account for
the high power torque events and the retirement lives of these bearing
bolts. Therefore, the FAA now proposes to require the RIN method of
accounting for high power torque events. The proposed AD would require
creation of a component history card using the RIN system;
establishment of a system for tracking increases to the accumulated
RIN; and establishment of a maximum accumulated RIN for the bearing
bolts of 17,000 before they must be removed from service.
Since this change expands the scope of the originally proposed
rule, the FAA has determined that it is necessary to reopen the comment
period to provide additional opportunity for public comment.
The FAA estimates that 54 helicopters of U.S. registry would be
affected by this proposed AD, and that it would take (1) 24 work hours
per helicopter to replace the affected bearing bolts due to the new
method of determining the retirement life; (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 $2,000 per helicopter. Based on
these figures, the total cost impact of the proposed AD on U.S.
operators is estimated to be $224,640 for the first year and $128,520
for each subsequent year. These costs assume replacement of the bearing
bolts in the fleet the first year, creation and maintenance of the
records for all the fleet; and replacement of one-half of the fleet's
bolts, creation of the records for one-half of the fleet, 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.
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.
[[Page 36379]]
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD), to read as follows:
Bell Helicopter Company, Inc. (BHTI): Docket No. 94-SW-23-AD.
Applicability: Model 214B and 214B-1 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 within 25 hours time-in-service (TIS),
unless accomplished previously.
To prevent fatigue failure of the pillow block bearing bolts
(bearing bolts), part number (P/N) 20-057-12-48D or -50D, which
could result in failure of the main rotor system and subsequent loss
of control of the helicopter, accomplish the following:
(a) Create a Retirement Index Number (RIN) component history
card or an equivalent record for the bearing bolts, P/N 20-057-12-
48D or -50D.
(b) Calculate and record on the component history card the
historical accumulated RIN for the bearing bolts as follows:
(1) When the type of operation (internal or external load lift),
actual flight hours, and number of external load lifts or takeoffs
per hour are known, multiply the actual flight hours by the
appropriate factor in the following table for external load lift
operation:
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Average No. of external load lift events per flight hour Factor
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0-2.00....................................................... 6.8
2.01-5.00.................................................... 13.6
5.01-16.00................................................... 27.2
16.01-27.00.................................................. 40.8
Above 27.00.................................................. 54.4
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When the type of operation is internal load and no external
lifting is involved, each hour of actual operating time is equal to
6.8 RIN.
(2) When the actual flight hours on the bolts are known, but the
type of operation (internal or external load lift) is unknown,
multiply the actual flight hours by a factor of 40.8.
(3) When the actual flight hours on the bolts are unknown,
assume 75 flight hours per month.
(4) When the flight hours on the bolts are assumed, but the type
of operation (internal or external load lift) is known,
(i) Multiply the number of flight hours assumed for internal
load operations by a factor of 6.8.
(ii) Multiply the number of flight hours assumed for external
load operations by a factor of 40.8.
(5) When the flight hours on the bolts are assumed and the type
of operation (internal or external load lift) is unknown, multiply
the assumed flight hours by a factor of 40.8.
(c) After compliance with paragraphs (a) and (b) of this AD,
during each operation thereafter, maintain a count of each lift or
takeoff performed and at the end of each day's operations, increase
the accumulated RIN on the bearing bolts component history card as
follows:
(1) Increase the RIN by 1 for each takeoff.
(2) Increase the RIN by 1 for each external load lift, or
increase the RIN by 2 for each external load 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.
Note 2: Bell Helicopter Textron, Inc. Alert Service Bulletin
214-94-54, dated November 7, 1994, pertains to the subject of this
AD.
(d) Remove the bearing bolts from service on or before attaining
an accumulated RIN of 17,000. The bearing bolts are no longer
retired based upon flight hours. If any of the four bolts require
replacement for any reason, then all four bolts must be replaced at
that time. This AD revises the Airworthiness Limitations section of
the maintenance manual by establishing a new retirement life for the
bearing bolts of 17,000 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,
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.
(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 June 23, 1998.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-17765 Filed 7-2-98; 8:45 am]
BILLING CODE 4910-13-P
