DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-1099; Product Identifier 2018-SW-026-AD]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for Airbus Helicopters Model EC 155B and EC155B1 helicopters. This
proposed AD would require modifying the wiring of the attitude and
heading reference system (AHRS) connector. This proposed AD is prompted
by a report of wiring of the AHRS contrary to approved design
specifications. The actions of this proposed AD are intended to address
an unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by April 28,
2020.

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

Federal eRulemaking Docket: Go to https://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 https://www.regulations.
gov by searching for and locating Docket No. FAA-2019-1099;
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, any
comments received, and other information. The street address for Docket
Operations is listed above. 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 https://
www.airbus.com/helicopters/services/technical-support.html. You may
review the 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: George Schwab, Aviation Safety
Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA,
10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-5110;
email george.schwab@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to participate in this rulemaking by submitting
written comments, data, or views. The FAA also invites 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.

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

Discussion

EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD No. 2018-0069, dated March 26, 2018
(EASA AD 2018-0069), to correct an unsafe condition for Airbus
Helicopters Model EC 155 B and EC 155 B1 helicopters. EASA advises that
the AHRS1 and AHRS2 on Model EC 155-series helicopters use the same
flight/ground signal contrary to the approved design specification,
which requires the AHRS1 and AHRS2 to use independent signals to ensure
redundancy. EASA states that if AHRS1 and AHRS2 both receive an
incorrect "ground" status due to a single failure while in flight, it
will generate an error in the computation of the attitude and vertical
speed and, as a result, an incorrect display of these indications to
the flight crew. EASA advises that this condition, if not corrected,
could lead to erroneous attitude and vertical speed indications,
resulting in increased workload for the flight crew and reduced control
of the helicopter during flight in instrument meteorological conditions
(IMC).

Accordingly, EASA AD 2018-0069 requires modifying the connection of
connector 11 ALPHA, and based on the helicopter configuration, also
modifying the wiring to connector 11 ALPHA.

FAA's Determination

These helicopters have been approved by EASA and are approved for
operation in the United States. Pursuant to the FAA's bilateral
agreement with the European Union, EASA has notified the FAA about the
unsafe condition described in its AD. The FAA is proposing this AD
after evaluating all known relevant information and determining that an
unsafe condition is likely to exist or develop on other helicopters of
the same type designs.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Airbus Helicopters Alert Service Bulletin (ASB)
No. EC155-34A033, Revision 2, dated January 30, 2018. This service
information specifies re-allocating the electronic board output
connections by modifying the wiring of connector 11 ALPHA for
helicopters with modification (MOD) 0722B51 installed and modifying the
wiring to connector 11 ALPHA for those helicopters that also have a
combined voice and flight data recording system (MOD 0731B89)
installed.

The FAA also reviewed Airbus Helicopters ASB No. EC155-34A037,
Revision 0, dated February 19, 2018. This service information specifies
installing MOD 0722B51 by modifying the wiring of connector 11 ALPHA to
separate the flight/ground information so the left-hand landing gear
flight information is also used by the automatic pilot system as well
as but separately from the right-hand landing gear flight information.
This service information also specifies re-allocating the electronic
board output connections by modifying the wiring of connector 11 ALPHA.

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

The FAA also reviewed Airbus Helicopters ASB No. EC155-34A033,
Revision 0, dated July 19, 2017, and Airbus Helicopters ASB No. EC155-
34A033, Revision 1, dated October 9, 2017. Revisions 0 and 1 of this
service information contain the same procedures for modifying the
wiring as Revision 2. However, Revision 1 clarifies the applicable
helicopter configurations and updates the post-modification testing
procedures, and Revision 2 clarifies the post-modification test
procedures and updates a figure.

Proposed AD Requirements

This proposed AD would require, before further flight in IMC or
within 660 hours time-in-service (TIS), whichever occurs first,
modifying the wiring at connector 11 ALPHA based on the helicopter
configuration and in accordance with specified portions of the
applicable ASB.

Differences Between This Proposed AD and the EASA AD

The compliance time for the EASA AD is within 7 or 12 months
depending on helicopter configuration. The compliance time for this
proposed AD would be before further flight in IMC or within 660 hours
TIS, whichever occurs first.

Costs of Compliance

The FAA estimates that this proposed AD affects 17 helicopters of
U.S. Registry. The FAA estimates that operators may incur the following
costs in order to comply with this proposed AD. Labor costs are
estimated at $85 per work-hour.

Modifying the wiring would take about 4 work-hours and parts would
cost about $20 for an estimated cost of $360 per helicopter and $6,120
for the U.S. fleet.

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.

The FAA is 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

The FAA 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) Will not affect intrastate aviation in Alaska, and

(3) 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.

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 adding the following new airworthiness
directive (AD):