DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1126; Product Identifier 2017-SW-125-AD]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH
(Previously Eurocopter Deutschland GmbH)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 97-26-03
for Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, MBB-BK 117 A-3,
MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1
helicopters. AD 97-26-03 requires visual inspections for cracks in the
ribbed area of the main rotor (M/R) mast flange (flange). Since we
issued AD 97-26-03, we have determined that a certain reinforced M/R
mast is not affected by the unsafe condition. This proposed AD would
retain the requirements of AD 97-26-03 and would remove a certain M/R
mast from the applicability. The actions of this proposed AD are
intended to address an unsafe condition on these products.

DATES: We must receive comments on this proposed AD by November 13, 2018.

ADDRESSES: You may send comments by any of the following methods:

Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the
online instructions for sending your comments electronically.

Fax: 202-493-2251.

Mail: Send comments to the U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590-0001.

Hand Delivery: Deliver to the "Mail" address between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2017-
1126; or in person at Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this proposed AD, the European Aviation Safety Agency (EASA) AD, the
economic evaluation, any comments received and other information. The
street address for Docket Operations (telephone 800-647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.

For service information identified in this proposed rule, contact
Airbus Helicopters, 2701 N. Forum Drive, Grand Prairie, TX 75052;
telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at
http://www.helicopters.airbus.com/website/en/ref/Technical-Support_73.
html. You may review this referenced service information at
the FAA, Office of the Regional Counsel, Southwest Region, 10101
Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177.

FOR FURTHER INFORMATION CONTACT: Matt Fuller, Senior Aviation Safety
Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA,
10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110;
email matthew.fuller@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to participate in this rulemaking by submitting
written comments, data, or views. We also invite comments relating to
the economic, environmental, energy, or federalism impacts that might
result from adopting the proposals in this document. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. To
ensure the docket does not contain duplicate comments, commenters
should send only one copy of written comments, or if comments are filed
electronically, commenters should submit only one time.

We will file in the docket all comments that we receive, as well as
a report summarizing each substantive public contact with FAA personnel
concerning this proposed rulemaking. Before acting on this proposal, we
will consider all comments we receive on or before the closing date for
comments. We will consider comments filed after the comment period has
closed if it is possible to do so without incurring expense or delay.
We may change this proposal in light of the comments we receive.

Discussion

We issued AD 97-26-03, Amendment 39-10246 (62 FR 65750, December
16, 1997) (AD 97-26-03) for Eurocopter Deutschland GmbH (now Airbus
Helicopters Deutschland GmbH) Model MBB-BK 117 A-1, MBB-BK 117 A-3,
MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1
helicopters. AD 97-26-03 requires visual inspections for cracks in the
ribbed area of the M/R flange and replacing the M/R mast if a crack is
found. AD 97-26-03 was prompted by AD 97-276, effective September 25,
1997, issued by Luftfahrt-Bundesamt (LBA), which is the airworthiness
authority for Germany, to correct an unsafe condition for Eurocopter
Deutschland GmbH Model MBB-BK 117 A-1, MBB-BK 117 A-3, MBB-BK 117 A-4,
MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1 helicopters. The LBA
AD required immediate and repetitive inspections for a crack in the
flange area after an M/R mast was found to have cracks "of critical
magnitude." When LBA AD 97-276 was issued, the cause of the cracks was
under investigation. The actions of AD 97-26-03 are intended to detect
cracks in the flange, which could result in failure of the flange and
subsequent loss of helicopter control.

Actions Since AD 97-26-03 Was Issued

Since we issued AD 97-26-03, EASA, which is the Technical Agent for
the Member States of the European Union, issued EASA AD No. 2017-0193,
dated September 29, 2017, to supersede the LBA AD. EASA advises that
reinforced M/R mast part number (P/N) 4639 305 095, which is part of M/
R mast assembly P/N 4639 205 016, is not affected by the unsafe
condition. The EASA AD retains the repetitive inspection requirements
but only for helicopters with M/R mast P/N 4639 305 002.

Also, since we issued AD 97-26-03, Eurocopter Deutschland GmbH
Helicopters changed its name to Airbus Helicopters Deutschland GmbH.
This proposed AD reflects that change and updates the contact
information to obtain service documentation.

Additionally, the FAA's Aircraft Certification Service has changed
its organizational structure. The new structure replaces product
directorates with functional divisions. We have revised some of the
office titles and nomenclature throughout this proposed AD to reflect
the new organizational changes. Additional information about the new
structure can be found in the Notice published on July 25, 2017 (82 FR
34564).

FAA's Determination

These helicopters have been approved by the aviation authority of
Germany and are approved for operation in the United States. Pursuant
to our bilateral agreement with Germany, EASA, its technical
representative, has notified us of the unsafe condition described in
its AD. We are proposing this AD because we evaluated all known
relevant information and determined that an unsafe condition is likely
to exist or develop on other products of the same type design.

Related Service Information Under 1 CFR Part 51

We reviewed Airbus Helicopters Alert Service Bulletin No. ASB MBB-
BK117-10-114, Revision 1, dated July 28, 2017. This service information
specifies visually inspecting the area of the holes on the underside of
the flange for cracks, especially in the ribbed area between the holes,
and if cracks are found, contacting Airbus Helicopters Deutschland GmbH
before further flight for advice on how to proceed. This service
information applies to helicopters with M/R mast assembly P/N
4639205011.

This service information is reasonably available because the
interested parties have access to it through their normal course of
business or by the means identified in the ADDRESSES section.

Other Related Service Information

We also reviewed Eurocopter Alert Service Bulletin No. ASB MBB-
BK117-10-114, dated August 27, 1997, which specifies visually
inspecting the area of the holes on the underside of the flange for
cracks, especially in the ribbed area between the holes, and if cracks
are found, contacting Eurocopter Helicopter Deutschland GmbH before
further flight for advice on how to proceed. This service information
applies to helicopters with M/R mast assembly P/N 4639205011 or
4639205016.

Proposed AD Requirements

This proposed AD would require before further flight and thereafter
at intervals not to exceed 100 hours time-in-service, visually
inspecting the flange in the ribbed area for a crack using a 5-power or
higher magnifying glass. If a crack exists, this proposed AD would
require removing the M/R mast before further flight and replacing it
with an airworthy M/R mast.

Differences Between This Proposed AD and the EASA AD

The EASA AD requires contacting Airbus Helicopters if a crack is
found on the flange for applicable instructions, whereas this proposed
AD would require replacing the M/R mast with an airworthy M/R mast
before further flight.

Costs of Compliance

We estimate that this proposed AD would affect 62 helicopters of
U.S. Registry and that labor costs average $85 per work-hour. Based on
these estimates, we expect the following costs:

Visually inspecting the flange for a crack would require
.25 work-hour and no parts for a cost of about $21 per helicopter and
$1,302 for the U.S. fleet per inspection cycle.

Replacing the M/R mast would require 10 work-hours and
parts would cost $50,000 for a cost of $50,850 per helicopter.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. "Subtitle VII: Aviation
Programs," describes in more detail the scope of the Agency's
authority.

We are issuing this rulemaking under the authority described in
"Subtitle VII, Part A, Subpart III, Section 44701: General
requirements." Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

Regulatory Findings

We determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed, I certify 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);

3. Will not affect intrastate aviation in Alaska to the extent that
it justifies making a regulatory distinction; and

4. 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.

We prepared an economic evaluation of the estimated costs to comply
with this proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD)
97-26-03, Amendment 39-10246 (62 FR 65750, December 16, 1997), and
adding the following new AD: