[Federal Register Volume 63, Number 62 (Wednesday, April 1, 1998)]
[Proposed Rules]
[Pages 15790-15791]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-8469]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-10-AD]


Airworthiness Directives; Bell Helicopter Textron Canada Model 
407 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Bell Helicopter Textron Canada 
(BHTC) Model 407 helicopters. This proposal would require shimming the 
tail rotor drive system bearing supports (bearing supports). This 
proposal is prompted by reports of cracked bearing hangar support arms 
in the area of the fillet radius. The actions specified by the proposed 
AD are intended to prevent failure of the bearing supports, which could 
result in excessive tail rotor drive system vibration, loss of tail 
rotor drive, and subsequent loss of control of the helicopter.

DATES: Comments must be received on or before May 1, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-10-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 Canada, 12,800 Rue de l'Avenir, 
Mirabel, Quebec JON1LO, telephone (800) 463-3036, fax (514) 433-0272. 
This information may be examined at the FAA, Office of the Regional 
Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, 
Texas.

FOR FURTHER INFORMATION CONTACT: Mr. Jurgen Priester, Aerospace 
Engineer, FAA, Rotorcraft Directorate, Rotorcraft Certification Office, 
2601 Meacham Blvd., Fort Worth, Texas 76137, (817) 222-5159, fax (817) 
222-5960.

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. 98-SW-10-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. 98-SW-10-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

Discussion

    Transport Canada, which is the airworthiness authority for Canada, 
recently notified the FAA that an unsafe condition may exist on BHTC 
Model 407 helicopters. Transport Canada advises that there have been 
some occurrences of a gap between the bearing support and the bearing 
hanger on the tailboom. They further advise that this situation, if not 
corrected, could lead to serious vibration of the tail rotor drive 
shaft, and eventually, to total disintegration of the shaft.
    BHTC has issued Bell Helicopter Textron Alert Service Bulletin No. 
407-97-7, dated February 27, 1997, which specifies a procedure for 
shimming

[[Page 15791]]

between the bearing supports and the bearing hangers on the tailboom. 
Transport Canada classified this service bulletin as mandatory and 
issued AD No. CF-97-08, dated May 30, 1997, in order to assure the 
continued airworthiness of these helicopters in Canada.
    This helicopter model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, Transport Canada has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of Transport Canada, reviewed all available information, and 
determined that AD action is necessary for products of this type design 
that are certificated for operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other BHTC Model 407 helicopters of the same type 
design registered in the United States, the proposed AD would require 
shimming the bearing supports within the next 25 hours time-in-service. 
The actions would be required to be accomplished in accordance with the 
service bulletin described previously.
    The FAA estimates that 160 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 4 work 
hours per helicopter to accomplish the shimming of the bearing support, 
and that the average labor rate is $60 per work hour. Required parts 
would cost approximately $30 per helicopter. Based on these figures, 
the total cost impact of the proposed AD on U.S. operators is estimated 
to be $43,200.
    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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
to read as follows:

Bell Helicopter Textron Canada: Docket No. 98-SW-10-AD.

    Applicability: Model 407 helicopters, serial numbers 53000, 
53002 through 53065, 53067, and 53069 through 53075, 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 (b) 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, unless 
accomplished previously.
    To prevent failure of the bearing supports, which could result 
in excessive tail rotor drive system vibration, loss of tail rotor 
drive, and subsequent loss of control of the helicopter, accomplish 
the following:
    (a) Shim the tail rotor drive system bearing supports in 
accordance with the Accomplishment Instructions contained in Bell 
Helicopter Textron Alert Service Bulletin No. 407-97-7, dated 
February 27, 1997.
    (b) 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, 
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.

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

    (c) 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.

    Note 3: The subject of this AD is addressed in Transport Canada 
(Canada) AD No. CF-97-08, dated May 30, 1997.

    Issued in Fort Worth, Texas, on March 24, 1998.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-8469 Filed 3-31-98; 8:45 am]
BILLING CODE 4910-13-P