[Federal Register Volume 61, Number 225 (Wednesday, November 20, 1996)]
[Proposed Rules]
[Pages 59034-59036]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-29609]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-SW-20-AD]


Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412 
and 412EP Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Bell Helicopter Textron, Inc. 
(BHTI) Model 412 and 412EP helicopters. This proposal would require 
creation of a component history card using a Retirement Index Number 
(RIN) system; would establish a system for tracking increases to the 
accumulated RIN; and would establish a maximum accumulated RIN for 
certain main rotor masts (masts) and main rotor spline plates (spline 
plates). This proposal is prompted by fatigue analyses and tests that 
show certain masts and spline plates fail earlier than originally 
anticipated because of an unanticipated high number of takeoffs and 
external load lifts utilizing high power settings, in addition to the 
time-in-service (TIS) accrued under normal operating conditions. The 
actions specified by the proposed AD are intended to prevent fatigue 
failure of the mast or spline plate, 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 21, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 94-SW-20-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., Product Support 
Department, 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-20-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.

[[Page 59035]]

94-SW-20-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

    This notice proposes the adoption of a new AD that is applicable to 
BHTI Model 412 and 412EP helicopters. This proposal would require, 
within the next 100 hours TIS, creation of a component history card 
using a RIN system for certain masts and spline plates used on the 
Model 412 and 412EP helicopters; would establish a system for tracking 
increases to the accumulated RIN; and would establish a retirement life 
of 80,000 RIN for certain helicopter masts and spline plates, and a 
retirement life of 60,000 RIN for certain other helicopter masts and 
spline. Fatigue analyses and tests by the manufacturer show that 
certain masts and spline plates fail earlier than originally 
anticipated because of an unanticipated high number of takeoffs and 
external load lifts utilizing high power settings in addition to the 
TIS accrued under normal operating conditions. This condition, if not 
corrected, could result in fatigue failure of the mast or spline plate, 
which could result in failure of the main rotor system and subsequent 
loss of control of the helicopter.
    The FAA has reviewed BHTI Alert Service Bulletin (ASB) No. 412-94-
81, Revision B, dated March 4, 1996, which describes procedures for 
creation of a component history card within the next 100 hours TIS for 
Model 412 and 412EP helicopters. The ASB also describes utilizing 
either a retirement life of 10,000 hours TIS or a maximum accumulated 
RIN of 80,000, whichever occurs first, for the BHTI Model 412 
helicopter mast and spline plate; and a retirement life of 10,000 hours 
TIS or a maximum accumulated RIN of 60,000, whichever occurs first, for 
the BHTI Model 412EP helicopter mast and spline plate.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other BHTI Model 412 and 412EP helicopters of the 
same type design, the proposed AD would require creation of a component 
history card using a RIN system for certain masts and spline plates, 
establishing a system for tracking increases to the accumulated RIN, 
and establishing a retirement life of 80,000 RIN for certain helicopter 
masts and spline plates, and a retirement life of 60,000 RIN for 
certain other helicopter masts and spline plates. Spline plates and 
masts used on Model 412EP helicopters will be vibro-etched with 
``412HP''. This identifier does not indicate FAA approval or 
certification of a Model 412HP helicopter.
    The FAA estimates that 294 helicopters of U.S. registry would be 
affected by this proposed AD, and that it would take (1) 8 work hours 
per helicopter to replace the mast and 10 work hours per helicopter to 
replace the spline plate; (2) 2 work hours per helicopter to create the 
component history card or equivalent record (record); (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 $21,635 per mast and $5,675 per spline plate. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators for the first year is estimated to be $1,602,790, and each 
subsequent year to be $1,573,390. These costs assume replacement of the 
mast and spline plate 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.

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 adding a new airworthiness directive 
to read as follows:

    Bell Helicopter Textron Inc.: Docket No. 94-SW-20-AD.

    Applicability: Model 412 and Model 412EP helicopters with main 
rotor mast (mast), part number (P/N) 412-040-101-105, -109, -117, -
121, -125, -127, or -129, and main rotor spline plate (spline plate) 
P/N 412-010-167-105 or P/N 412-010-177-101, -105, -109, -113, or -
117, 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 100 hours time-in-service (TIS) 
after the effective date of this AD, unless accomplished previously.
    To prevent fatigue failure of the mast and spline plate, 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 
each affected mast and spline plate. Record the accumulated 
Retirement Index Number (RIN) on the mast and spline plate component 
history card(s) as follows:
    (1) If the numbers of takeoffs (at any gross weight) and 
external load lift events are known, and those numbers do not 
include any external load operation in which the load was 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 was 200 feet or greater (high power lift event), increase the 
accumulated RIN by one for each takeoff and external load lift.
    (2) If the numbers of takeoffs (at any gross weight) and 
external load lifts are known, and the number of external load lifts 
includes a high power lift event, increase the accumulated RIN by 
two for each takeoff and two for each external load lift.
    (3) For each hour time-in-service (TIS) for which the numbers of 
takeoffs and external

[[Page 59036]]

load lifts are unknown, and the number of external load lifts does 
not include a high power lift event, increase the accumulated RIN by 
10 for each hour TIS.
    (4) For each hour TIS for which the numbers of takeoffs and 
external load lifts are unknown, but the number of external load 
lifts does include a high power lift event, increase the accumulated 
RIN by 20 for each hour TIS.
    (5) For each hour TIS for which the numbers of takeoffs and 
external load lifts are unknown, and it is unknown whether the 
external load lifts include any high-power lift event, increase the 
accumulated RIN by 20 for each hour TIS.
    (b) After compliance with paragraph (a) 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 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.
    (c) Retire the mast and spline plate in accordance with the 
following:
    (1) For the mast, part number (P/N) 412-040-101-105, 109, -117, 
or -127, used on the Model 412 helicopter upon reaching 10,000 hours 
TIS or 80,000 maximum RIN, whichever occurs first.
    (2) For the mast, P/N 412-040-101-121, -125, or -129, used on 
the Model 412EP helicopter, upon reaching 10,000 hours TIS or 60,000 
maximum RIN, whichever occurs first.
    (3) For the spline plate, P/N 412-010-167-105 or P/N 412-010-
177-101, or -109, used on the Model 412 helicopter, at 10,000 hours 
TIS or 80,000 maximum RIN, whichever occurs first.
    (4) For the spline plate, P/N 412-010-167-105 or P/N 412-010-
177-101, -105, -113, or -117, used on the Model 412EP helicopter, at 
10,000 hours TIS or 60,000 maximum RIN, whichever occurs first.
    (d) For spline plate, P/N 412-010-167-105 or P/N 412-010-177-
101, -105, -113, or -117, installed on Model 412EP helicopters, at 
the next scheduled teardown inspection, beside the P/N on the side 
of the spline plate, vibro-etch ``412HP'' and annotate in the 
component history card or equivalent record ``412HP/EP only'' to 
reflect that this spline plate can only be installed on the Model 
412EP helicopter, and not on any other Model 412 helicopter. Retire 
the spline plates that have been vibro-etched with ``412HP'' on or 
before accumulating 10,000 hours TIS or 60,000 RIN, whichever occurs 
first.

    Note 2: Bell Helicopter Textron, Inc. Alert Service Bulletin No. 
412-94-81, Revision B, dated March 4, 1996, pertains to this 
subject.

    (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 November 6, 1996.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-29609 Filed 11-19-96; 8:45 am]
BILLING CODE 4910-13-U