Airworthiness Directives; Eurocopter Deutschland GMBH Model MBB- BK 117 Helicopters

[Federal Register Volume 64, Number 237 (Friday, December 10, 1999)]
[Proposed Rules]
[Pages 69208-69209]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-32085]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-77-AD]


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 adoption of a new airworthiness 
directive (AD) that is applicable to Eurocopter Deutschland Model MBB-
BK 117 helicopters. This proposal would change the retirement life for 
the tail rotor (output) drive bevel gear (bevel gear). This proposal is 
prompted by a fatigue analysis of the bevel gear conducted by the 
manufacturer due to installation of different tail rotor blades. The 
actions specified by the proposed AD are intended to prevent fatigue 
failure of the bevel gear, loss of tail rotor drive, and subsequent 
loss of control of the helicopter.

DATES: Comments must be received on or before February 8, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-77-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas. Comments may be inspected at this location between 
9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.

FOR FURTHER INFORMATION CONTACT: Shep Blackman, Aerospace Engineer, 
FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham 
Blvd., Fort Worth, Texas 76137, telephone (817) 222-5296, 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. 98-SW-77-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-77-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

Discussion

    The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority 
for the Federal Republic of Germany, has notified the FAA that an 
unsafe condition may exist on Eurocopter Deutschland Model MBB-BK117 
helicopters. The LBA advises that the working life of the tail rotor 
(output) drive unit of the main transmission has been recalculated, 
requiring the introduction of a life limitation of 18,500 hours time-
in-service (TIS) on the bevel gear, part number 117-12215-01.
    Eurocopter Deutschland GMBH has issued Eurocopter Deutschland GMBH 
Alert Service Bulletin MBB-BK 117 No. ASB-MBB-BK 117-10-113, dated 
September 30, 1997, which specifies entering a life limitation in the 
accessory replacement record and historical record ``Main 
Transmission'' section not later than December 31, 1997. The LBA 
classified this service bulletin as mandatory and issued AD No. 97-350, 
dated December 18, 1997, in order to assure the continued airworthiness 
of these helicopters in the Federal Republic of Germany.
    This helicopter model is manufactured in the Federal Republic of 
Germany 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, the LBA 
has kept the FAA informed of the situation described above. The FAA has 
examined the findings of the LBA, 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 Eurocopter Deutschland Model MBB-BK117 
helicopters of the same type design registered in the United States, 
the proposed AD would require entering a recalculated life limitation 
for the bevel gear in the accessory replacement record and historical 
record ``Main Transmission'' section, determining the total operating 
time of the bevel gear, and replacing the bevel gear upon reaching the 
life limit of 18,500 hours TIS.

Cost Impact

    The FAA estimates that 130 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 0.5 work 
hour per helicopter to change the retirement life in the records, and 
36 work hours to replace the bevel gear. The average labor rate is $60 
per work hour. Required parts would cost approximately $14,092 per 
helicopter. Based on these figures, the total cost impact of the 
proposed AD on U.S. operators is estimated to be $2,116,660 to change 
the retirement life entry and to replace the bevel gear upon reaching 
18,500 hours TIS for the entire fleet.

Regulatory Impact

    The regulations proposed herein would not impose substantial direct 
compliance costs on any states or local government or 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 13132, the FAA has not consulted with 
any states or local authorities prior to publication of the proposed 
rule.
    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

[[Page 69209]]

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:

Eurocopter Deutschland: Docket No. 98-SW-77-AD.

    Applicability: Model MBB-BK 117 helicopters, serial numbers 7001 
through 7250 and 7500 through 7509, 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 helicopter 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 (d) 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 as indicated, unless accomplished 
previously.
    To prevent fatigue failure of the tail rotor (output) drive 
bevel gear (bevel gear), loss of tail rotor drive, and subsequent 
loss of control of the helicopter, accomplish the following:
    (a) Within 100 hours time-in-service (TIS):
    (1) Record in the accessory replacement record and historical 
record ``Main Transmission'' section the retirement life of 18,500 
hours TIS for the bevel gear.
    (2) Determine the total hours TIS of the bevel gear. If the 
total hours TIS cannot be determined, use the operating time of the 
main transmission.
    (b) If the bevel gear's total hours TIS is equal to or greater 
than 18,400 hours TIS, remove the bevel gear within the next 100 
hours TIS and replace it with an airworthy bevel gear. If the bevel 
gear's total hours TIS is less than 18,400 hours TIS, remove the 
bevel gear on or before 18,500 hours TIS and replace it with an 
airworthy bevel gear.
    (c) This AD revises the helicopter Airworthiness Limitations 
section of the maintenance manual by establishing a new retirement 
life for the bevel gear of 18,500 hours TIS.
    (d) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used when approved by the Manager, Regulations Group, Rotorcraft 
Directorate, FAA. Operators shall submit their requests through a 
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 
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 Luftfahrt-
Bundesamt (Federal Republic of Germany) AD No. 97-350, dated 
December 18, 1997.

    Issued in Fort Worth, Texas, on December 3, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-32085 Filed 12-9-99; 8:45 am]
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