DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1037; Project Identifier 2019-SW-077-AD; Amendment
39-21407; AD 2021-03-04]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Airbus Helicopters Deutschland GmbH Model EC135P1, EC135P2,
EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, and EC135T3 helicopters.
This AD requires removing certain Titanium (Ti) bolts from service and
prohibits installing these Ti-bolts in a critical area. This AD was
prompted by a report of a broken Ti-bolt. The actions of this AD are
intended to address an unsafe condition on these products.

DATES: This AD is effective March 29, 2021.

ADDRESSES: For service information identified in this final 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 view the referenced service information at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321,
Fort Worth, TX 76177.

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-
1037; 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 AD, the European Union Aviation Safety Agency (EASA) AD, any
comments received, and other information. The street address for Docket
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue
SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Katherine Venegas, Aviation Safety
Engineer, Los Angeles ACO, FAA, 3960 Paramount Blvd., Lakewood, CA
90712; telephone 562-627-5353; email katherine.venegas@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 Airbus Helicopters
Deutschland GmbH Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1,
EC135T2, EC135T2+, and EC135T3 helicopters with a Ti-bolt part number
(P/N) L535M2001203 marked with manufacturer monogram ``D'' or with an
illegible manufacturer monogram installed on the forward tail rotor (T/
R) drive shaft. The NPRM published in the Federal Register on November
30, 2020 (85 FR 76490). The NPRM proposed to require removing any
affected Ti-bolt installed on the forward T/R drive shaft from service
and prohibit installing an affected Ti-bolt on the forward T/R drive
shaft of any helicopter. The proposed requirements were intended to
prevent failure of an affected Ti-bolt installed in a critical
location, possibly resulting in reduced control of the helicopter.
The NPRM was prompted by EASA AD No. 2019-0199, dated August 16,
2019, issued by EASA, which is the Technical Agent for the Member
States of the European Union, to correct an unsafe condition for Airbus
Helicopters Deutschland GmbH (AHD), formerly Eurocopter Deutschland
GmbH, Eurocopter Espa[ntilde]a S.A., Model EC135 P1, EC135 P2, EC135
P2+, EC135 P3, EC135 T1, EC135 T2, EC135 T2+, EC135 T3, EC635 P2+,
EC635 P3, EC635 T1, EC635 T2+, and EC635 T3 helicopters. EASA advises
of a report of a broken Ti-bolt. Subsequent investigation revealed that
an improper heat treatment process was accomplished on a batch of Ti-
bolts, which can lead to hydrogen embrittlement. The investigation also
identified the critical location where these Ti-bolts are installed on
helicopters. According to EASA, this condition, if not detected and
corrected, could lead to failure of an affected Ti-bolt installed in a
critical location, possibly resulting in reduced control of the
helicopter. Accordingly, the EASA AD requires a one-time inspection of
Ti-bolt P/N L535M2001203 marked with
manufacturer monogram ``D'' or with an illegible manufacturer monogram
installed on the forward T/R drive shaft and, depending on the
inspection results, replacing the Ti-bolt. The EASA AD also prohibits
the (re)installation of these Ti-bolts.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule, but the FAA did not receive any comments on
the NPRM or on the determination of the cost to the public.

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 of the
unsafe condition described in its AD. The FAA is issuing this AD after
evaluating all of the information provided by EASA and determining the
unsafe condition exists and is likely to exist or develop on other
helicopters of these same type designs and that air safety and the
public interest require adopting the AD requirements as proposed.

Differences Between This AD and the EASA AD

The EASA AD applies to Model EC135 P1, EC135 P2, EC135 P2+, EC135
P3, EC135 T1, EC135 T2, EC135 T2+, EC135 T3, EC635 P2+, EC635 P3, EC635
T1, EC635 T2+, and EC635 T3 helicopters and requires inspecting Ti-bolt
P/N L535M2001203 marked with manufacturer monogram ``D'' or with an
illegible manufacturer monogram installed on the forward T/R drive
shaft. This AD applies to Model EC135P1, EC135P2, EC135P2+, EC135P3,
EC135T1, EC135T2, EC135T2+, and EC135T3 helicopters with a Ti-bolt P/N
L535M2001203 marked with manufacturer monogram ``D'' or with an
illegible manufacturer monogram installed on the forward T/R drive
shaft instead. This AD does not apply to Model EC635 P2+, EC635 P3,
EC635 T1, EC635 T2+, or EC635 T3 helicopters because these models are
not FAA type-certificated. The EASA AD requires discarding the affected
Ti-bolts, whereas this AD requires removing the affected Ti-bolts from
service instead.

Related Service Information

The FAA reviewed Airbus Helicopters Alert Service Bulletin (ASB)
No. EC135-00A-001, Revision 1, dated September 2, 2019, for Airbus
Helicopters Deutschland GmbH Model EC135 T1, T2, T2+, T3, P1, P2, P2+,
P3, 635 T1, 635 T2+, 635 T3, 635 P2+, and 635 P3 helicopters, and
Airbus Helicopters ASB No. EC135H-00A-001, Revision 1, dated September
2, 2019, for Airbus Helicopters Deutschland GmbH Model EC135, T3H, P3H,
635 T3H, and 635 P3H helicopters. This service information specifies
inspecting the forward T/R drive shaft, distance plate of the 5B-0.50-
2.50P-XN-1 antenna, main rotor controls, FWD connection of ball bearing
control, and AFT connection of ball bearing control and yaw actuator
for the installation of Ti-bolt P/N L535M2001203, EN3308-040020F,
L221M1040201, EN3740-060020F, and EN3308-060020F, marked with
manufacturer monogram ``D'' or an illegible manufacturer monogram. If a
specified Ti-bolt is installed, the service information specifies
replacing the Ti-bolt and discarding the removed Ti-bolt.

Costs of Compliance

The FAA estimates that this AD affects 326 helicopters of U.S.
Registry. Labor rates are estimated at $85 per work-hour. Based on
these numbers, the FAA estimates that operators may incur the following
costs in order to comply with this AD.
Replacing a Ti-bolt takes about four work-hours and parts cost
about $82 for an estimated cost of $422 per Ti-bolt.

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 helicopters 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: