DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0462; Product Identifier 2019-SW-021-AD; Amendment
39-21309; AD 2020-22-13]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Airbus Helicopters Model AS332C1 and AS332L1 helicopters. This
AD was prompted by a report that the affected helicopters use the same
``flight/ground'' logic signal, instead of independent redundant
signals. This AD requires amending the emergency procedures of the
existing rotorcraft flight manual (RFM) for your helicopter, a wiring
modification of the ``flight/ground'' logic signal source of the
attitude and heading reference system (AHRS) 1, and then removal of the
amendment to the existing RFM for your helicopter. The FAA is issuing
this AD to address the unsafe condition on these products.

DATES: This AD is effective December 8, 2020.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of December 8,
2020.

ADDRESSES: For service information identified in this final rule,
contact Airbus Helicopters, 2701 N Forum Drive, Grand Prairie, TX
75052; phone: (972) 641-0000 or (800) 232-0323; fax: (972) 641-3775; or
at https:// www.airbus.com/helicopters/services/hnical-support.html. You may view
this service information at the FAA, Office of the Regional Counsel,
Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX
76177. For information on the availability of this material at the FAA,
call 817-222-5110.

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-2020-0462;
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 final rule, the European Aviation Safety Agency (now European
Union Aviation Safety Agency) (EASA) AD, any comments received, and
other information. The street address for Docket Operations is listed
above.

FOR FURTHER INFORMATION CONTACT: George Schwab, Aviation Safety
Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA,
10101 Hillwood Pkwy., Fort Worth, TX 76177; phone: 817-222-5110; email:
george.schwab@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to certain Airbus
Helicopters Model AS332C1 and AS332L1 helicopters. The NPRM published
in the Federal Register on June 4, 2020 (85 FR 34375). The NPRM was
prompted by a report that the affected helicopters use the same
``flight/ground'' logic signal instead of independent redundant
signals. The NPRM proposed to require amending the emergency procedures
of the existing RFM for your helicopter, a wiring modification of the
``flight/ground'' logic signal source of the AHRS 1, and then removal
of the amendment to the existing RFM for your helicopter. The FAA is
issuing this AD to address certain helicopters that use the same
``flight/ground'' logic signal, instead of independent redundant
signals. If both AHRS incorrectly receive ``ground'' status in flight,
as a result for instance of a single failure, this will generate
consistent erroneous computation of the attitudes and vertical speed
during helicopter maneuvers with consequent incorrect flight data
indications to the flight crew on both primary displays. Erroneous
flight information could lead to increased workload for the flight crew
when the upper modes of the automatic flight control system are not
engaged, possibly resulting in reduced control of the helicopter during
high speed maneuvers in instrumental meteorological conditions (IMC).
EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD 2019-0021, dated February 1, 2019;
corrected February 4, 2019 (EASA AD 2019-0021) (referred to after this
as the Mandatory Continuing Airworthiness Information, or ``the
MCAI''), to correct an unsafe condition for certain Airbus Helicopters
Model AS332C1 and AS332L1 helicopters. EASA advises that the AHRS 1 and
AHRS 2 installed on AS332C1e and AS332L1e helicopters use the same
``flight/ground'' logic signal, instead of independent redundant
signals, as required by the original design specification. If both AHRS
incorrectly receive ``ground'' status in flight, as a result for
instance of a single failure, this will generate consistent erroneous
computation of the attitudes and vertical speed during helicopter
maneuvers with consequent incorrect flight data indications to the
flight crew on both primary displays. EASA AD 2019-0021 states that
this condition, if not corrected, could lead to increased workload for
the flight crew when the upper modes of the automatic flight control
system are not engaged, possibly resulting in reduced control of the
helicopter during high speed maneuvers in IMC.
EASA further advises that Airbus Helicopters has issued rush
revisions to the RFM, and developed a modification of the wiring
harness, ensuring independent sources of the ``flight/ground'' logic
signal for both AHRS. EASA AD 2019-0021 requires amending the emergency
procedures of the applicable RFM, doing the modification of the wiring
harness, and then removing the amendment to the RFM.
You may examine the MCAI in the AD docket on the internet at
https://www.regulations.gov by searching for and locating Docket No.
FAA-2020-0462.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule. The FAA received no comments on the NPRM or
on the determination of the cost to the public.

Conclusion

The FAA reviewed the relevant data and determined that air safety
and the public interest require adopting this final rule as proposed,
except for minor editorial changes.
The FAA has determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

Airbus Helicopters has issued Alert Service Bulletin No. AS332-
34.00.60, Revision 1, dated March 29, 2019. This service information
describes procedures for a wiring modification of the ``flight/ground''
logic signal source of the AHRS 1, which changes the ``flight/ground''
logic signal source to independent redundant signals.
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

Airbus Helicopters has issued Alert Service Bulletin No. AS332-
34.00.60, Revision 0, dated December 6, 2018. The service information
describes procedures for a wiring modification of the ``flight/ground''
logic signal source of the AHRS 1, which changes the ``flight/ground''
logic signal source to independent redundant signals. Airbus Service
Bulletin No. AS332-34.00.60, Revision 1, dated March 29, 2019,
clarifies the procedures for the post-installation test in Alert
Service Bulletin No. AS332-34.00.60, Revision 0, dated December 6,
2018.

Differences Between This AD and the MCAI or Service Information

EASA AD 2019-0021 specifies to do the modification within 6 months.
This AD requires the modification be done within 100 hours time-in-
service or before intentional flight into IMC, whichever occurs first.
The FAA has determined this compliance time represents the maximum
interval of time allowable for the affected helicopters to continue to
safely operate before the modification is done.

Costs of Compliance

The FAA estimates that this AD affects 8 helicopters of U.S.
registry. The FAA estimates the following costs to comply with this AD:

Estimated Costs for Required Actions

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

This AD will not have federalism implications under Executive Order
13132. This AD will 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 above, I certify that this AD:
(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.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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: