[Federal Register Volume 65, Number 181 (Monday, September 18, 2000)]
[Proposed Rules]
[Pages 56275-56276]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-23861]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-SW-67-AD]
RIN 2120-AA64


Airworthiness Directives; Eurocopter Deutschland GMBH Model MBB-
BK 117 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 directive (AD) for Eurocopter Deutschland GMBH (ECD) 
Model MBB-BK 117 helicopters. That AD currently requires, before 
further flight, creating a component log card or equivalent record and 
determining the calendar age and number of flights on each tension-
torsion (TT) strap. This action would establish a life limit for 
certain main rotor TT straps. This proposal is prompted by an accident 
in which a main rotor blade (blade) separated from an ECD Model MBB-BK 
117 helicopter due to fatigue failure of a TT strap. The actions 
specified by this AD are intended to prevent fatigue failure of a TT 
strap, loss of a blade, and subsequent loss of control of the 
helicopter.

DATES: Comments must be received on or before November 17, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 99-SW-67-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137. You may also send comments electronically to 
the Rules Docket at the following address: [email protected]. 
Comments may be inspected at the Office of the Regional Counsel between 
9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Charles Harrison, Aviation Safety 
Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort 
Worth, Texas 76193-0110, telephone (817) 222-5128, 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 mailed 
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. 99-SW-67-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. 99-SW-67-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

Discussion

    On January 5, 2000, the FAA issued AD 2000-01-11, Amendment 39-
11509 (65 FR 2017, January 13, 2000), applicable to ECD Model MBB-BK 
117 helicopters. That AD currently requires, before further flight, 
creating a component log card or equivalent record and determining the 
age and number of flights on each TT strap. Also, AD 2000-01-11 
requires inspecting and removing, as necessary, certain unairworthy TT 
straps. That action was prompted by an accident in which a blade 
separated from an ECD Model MBB-BK 117 helicopter due to fatigue 
failure of a TT strap. The requirements of that AD are intended to 
prevent failure of a TT strap, loss of a blade, and subsequent loss of 
control of the helicopter.
    Since the issuance of that AD, we have determined the need to 
establish a life limit for the TT strap. We have also determined that 
the graduated inspection criteria and the accompanying TT strap lives 
specified in the current AD are no longer necessary after a life limit 
is established.
    ECD issued Alert Service Bulletin MBB-BK 117 No. ASB-MBB-BK 117-10-
120, Revision 1, dated August 31, 1999 (ASB). The ASB describes 
procedures for determining the total accumulated installation time and 
number of flights on each TT strap. The ASB also specifies inspecting 
and replacing, as necessary, certain unairworthy TT straps. The ASB 
further states that certain TT straps must be renumbered prior to 
installation. The Luftfahrt Bundesamt (LBA), the airworthiness 
authority for the Federal Republic of Germany, classified this ASB as 
mandatory and issued AD 1999-284/2, dated September 1, 1999, to ensure 
the continued airworthiness of these helicopters in the Federal 
Republic of Germany.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other ECD Model MBB-BK 117 helicopters registered 
in the United States, the proposed AD would require establishing a life 
limit for the TT straps of 120 months or 25,000 flights, whichever 
occurs first.
    The FAA estimates that 127 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 16 work 
hours per helicopter to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $10,400 per helicopter. Based on these figures, the total 
cost impact of the proposed AD on U.S. operators is estimated to be 
$1,442,720.
    The regulations proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal does not have federalism implications 
under Executive Order 13132.
    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

[[Page 56276]]

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 removing Amendment 39-11509 (65 FR 
2017, January 13, 2000), and by adding a new airworthiness directive 
(AD), to read as follows:

Eurocopter Deutschland GMBH: Docket No. 99-SW-67-AD. Supersedes AD 
2000-01-11, Amendment 39-11509, Docket No. 99-SW-60-AD.

    Applicability: Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-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 
otherwise 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 request approval for an 
alternative method of compliance in accordance with paragraph (d) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent fatigue failure of a tension-torsion (TT) strap, loss 
of a main rotor blade (blade), and subsequent loss of control of the 
helicopter, accomplish the following:
    (a) Before further flight,
    (1) Remove TT straps, P/N 2604067 (Bendix) or J17322-1 (Lord), 
from service or re-identify them as P/N 117-14110 or 117-14111, 
respectively, in accordance with the Accomplishment Instructions, 
paragraph 2.B.1.2., Eurocopter Deutschland GMBH Alert Service 
Bulletin MBB-BK-117 No. ASB-MBB-BK 117-10-120, Revision 1, dated 
August 31, 1999 (ASB). TT straps, P/N 2604067 (Bendix) or J17322-1 
(Lord), are no longer eligible for installation.
    (2) Create a component log card or equivalent record for each TT 
strap.
    (3) Review the history of the helicopter and each TT strap. 
Determine the age since initial installation on any helicopter (age) 
and the number of flights on each TT strap. Enter both the age and 
the number of flights for each TT strap on the component log card or 
equivalent record. When the number of flights is unknown, multiply 
the number of hours time-in-service (TIS) by 5 to determine the 
number of flights.
    (4) Remove any TT strap from service if the total hours TIS or 
number of flights and age cannot be determined
    (b) Before further flight, remove any TT strap, part number (P/
N) 117-14110 or 117-14111, that has been in service 120 months since 
initial installation on any helicopter or accumulated 25,000 flights 
(a flight is a takeoff and a landing). Replace the TT strap with an 
airworthy TT strap.
    (c) This AD revises the Airworthiness Limitations Section of the 
maintenance manual by establishing a life limit for the TT strap, P/
N 117-14110 and 117-14111, of 120 months or 25,000 flights, 
whichever occurs first.
    (d) 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, Regulations Group, 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, Regulations Group.

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

    (e) Special flight permits may be issued in accordance with 
Secs. 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 the Luftfahrt 
Bundesamt (Federal Republic of Germany) AD 1999-284/2, dated 
September 1, 1999.


    Issued in Fort Worth, Texas, on September 8, 2000.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 00-23861 Filed 9-15-00; 8:45 am]
BILLING CODE 4910-13-U