DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1037; Project Identifier 2019-SW-077-AD]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Airbus Helicopters Deutschland GmbH Model EC135P1, EC135P2,
EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, and EC135T3 helicopters.
This proposed AD would require removing certain Titanium (Ti) bolts
from service and prohibit installing these Ti-bolts in a critical area.
This proposed AD was prompted by a report of a broken Ti-bolt. The FAA
is proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by January 14,
2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the
instructions for submitting comments.

Fax: 202-493-2251.

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

Hand Delivery: Deliver to Mail address above 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-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 NPRM, the European Union 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 NPRM, 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 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.

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:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2020-1037; Product Identifier
2019-SW-077-AD" at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.

Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this proposal.

Confidential Business Information

CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as "PROPIN." The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to
Katherine Venegas, Aviation Safety Engineer, Los Angeles ACO, FAA, 3960
Paramount Blvd., Lakewood, CA 90712; telephone 562-627-5353; email
katherine.venegas@faa.gov. Any commentary that the FAA receives that is
not specifically designated as CBI will be placed in the public docket
for this rulemaking.

Discussion

EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD No. 2019-0199, dated August 16,
2019, 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 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 and, depending on the inspection results,
replacing the Ti-bolt. The EASA AD also prohibits the (re)installation
of these Ti-bolts.

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
these same type designs.

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.

Proposed AD Requirements

This proposed AD would require removing any Ti-bolt P/N
L535M2001203 marked with manufacturer monogram "D" or with an
illegible manufacturer monogram installed on the forward T/R drive
shaft from service. This proposed AD would also prohibit installing an
affected Ti-bolt on the forward T/R drive shaft of any helicopter.

Differences Between This Proposed 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 proposed 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 proposed 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 proposed AD would require removing
the affected Ti-bolts from service instead.

Costs of Compliance

The FAA estimates that this proposed 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 proposed AD.

Replacing a Ti-bolt would take about four work-hours and parts
would 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 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 above, 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: