DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1033; Project Identifier MCAI-2020-01393-R;
Amendment 39-21622; AD 2021-13-17]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2017-17-
01, which applied to certain Airbus Helicopters Model AS332L2 and
EC225LP helicopters. AD 2017-17-01 required repetitive inspections of
the main rotor blade (MRB) attachment pins. This AD continues to
require the repetitive inspections of the MRB attachment pins, and also
requires repetitive measurement of the attachment pin chamfer at
certain intervals after corrosion removal, as specified in a European
Aviation Safety Agency (now European Union Aviation Safety Agency)
(EASA) AD, which is incorporated by reference. This AD was prompted by
the FAA's determination that it is necessary to measure the attachment
pin chamfer after corrosion removal, that replacement of an attachment
pin after four corrosion removals is no longer necessary, and that all
Airbus Helicopters Model AS332L2 and EC225LP helicopters are affected
by the unsafe condition. The FAA is issuing this AD to address the
unsafe condition on these products.

DATES: This AD is effective August 17, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of August 17,
2021.

ADDRESSES: For material incorporated by reference (IBR) in this AD,
contact the EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany;
phone: +49 221 8999 000; email: ADs@easa.europa.eu; internet:
www.easa.europa.eu. You may find this material on the EASA website at
https://ad.easa.europa.eu. You may view this material 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. It is also available in
the AD docket on the internet at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-1033.

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-
1033; 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, any comments received, and other information. The
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, Cabin Safety, Mechanical and Environmental Systems Section,
Los Angeles ACO Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA
90712-4137; phone: 562-627-5353; email: katherine.venegas@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD 2018-0172, dated August 7, 2018
(EASA AD 2018-0172) (also referred to as the Mandatory Continuing
Airworthiness Information, or the MCAI), to correct an unsafe condition
for all Airbus Helicopters Model AS332L2 and EC225LP helicopters. EASA
AD 2018-0172 superseded EASA AD 2015-0016, dated January 30, 2015
(which prompted FAA AD 2017-17-01, Amendment 39-18991 (82 FR 39506,
August 21, 2017) (AD 2017-17-01)).
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2017-17-01. AD 2017-17-01 applied to
certain Airbus Helicopters Model AS332L2 and EC225LP helicopters. The
NPRM published in the Federal Register on November 24, 2020 (85 FR
74931). The NPRM was prompted by the FAA's determination that it is
necessary to measure the attachment pin chamfer after corrosion
removal, that replacement of an attachment pin after four corrosion
removals is no longer necessary, and that all Airbus Helicopters Model
AS332L2 and EC225LP helicopters are affected by the unsafe condition.
The NPRM proposed to continue to require the repetitive inspections of
the MRB attachment pins, as specified in an EASA AD. The NPRM also
proposed to require repetitive measurement of the attachment pin
chamfer at certain intervals after corrosion removal, as specified in
an EASA AD.
The FAA is issuing this AD to address cracked MRB attachment pins
which could result in loss of an MRB and subsequent loss of control of
the helicopter. See the MCAI for additional background information.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule. The following presents the comments
received on the NPRM and the FAA's response to each comment.

Request To Allow Rework of Corrosion Pits

Air Center Helicopters, Inc. (ACH) and Airbus Helicopters (AH)
requested that the FAA allow rework of corrosion pits. ACH disagreed
with the FAA's determination to disallow blade pin rework, and stated
that scrapping blade pins due to disallowing rework is fiscally
irresponsible, due to substantial replacement costs (each main rotor
hub has 10 blade pins). ACH pointed out that since the FAA issued AD
2017-17-01, ACH has removed and reworked numerous corrosion pitted
EC225 blade pins from service in accordance with Airbus Helicopters
Alert Service Bulletin EC225-05A040. ACH discussed that in many cases
the corrosion pitting was nearly undetectable using 10X magnification,
and that additional inspections were done using a 0.005 inch ball
gauge. ACH also mentioned that visible corrosion pitting was often
undetectable using the ball gauge, and pointed out that to ACH, the
undetectable corrosion pitting indicated that the blade pin was
salvageable with a minimum of rework.
ACH agreed with not allowing blade pin rework in FAA AD 2017-17-01
because Revision 0 of Airbus Helicopters Alert Service Bulletin EC225-
05A040 did not specify a method to determine dimensional airworthiness
after rework. ACH stated that Revision 1 of Airbus Helicopters Alert
Service Bulletin EC225-05A040, included post rework inspection
procedures and dimensional criteria for post rework blade pin
airworthiness, and that Revision 2 of Airbus Helicopters Alert Service
Bulletin EC225-05A040 introduced a maximum radius to the caliper points
of 0.6 mm (0.0236 inch) to ensure the point seats properly within the
external blade pin blend radius ensuring accurate wall thickness
measurements. ACH specified that Airbus Helicopters Alert Service
Bulletin EC225-05A040 provides a definitive procedure for inspection
and verification of blade pin airworthiness after corrosion pitting
rework, and that the procedure was approved by EASA.
ACH and AH argued that the term ``corrosion'' in Airbus Helicopters
Alert Service Bulletin EC225-05A040, is intended to include corrosion
pitting. AH pointed out that the service information is currently at
Revision 2, that the revision was based on research and feedback from
customer reports, and implemented detailed inspection procedures and
measurements to determine airworthiness of the blade pins. AH then
stated that the FAA did not reflect the intentions of the latest
service information.
The FAA disagrees with the request. Although the MCAI and service
information specify rework in case corrosion is found, neither clearly
address action in the case of corrosion pitting. Corrosion pitting is
different than uniform corrosion and can be more dangerous.
Additionally, the FAA does not agree with the inference that the
intention of the service information is to allow rework of corrosion
pits. The FAA has not revised this AD in this regard.

Conclusion

The FAA reviewed the relevant data, considered the comments
received, 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

EASA AD 2018-0172 specifies procedures for repetitive inspections
for corrosion and cracking of the attachment pins and corrective
actions if necessary, and repetitive conditional measurement of the
thickness of the chamfer of the attachment pins at certain intervals
after corrosion removal. Corrective actions include corrosion removal
and replacement of the attachment pins. This material 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.

Differences Between This Proposed AD and the MCAI

EASA AD 2018-0172 requires an inspection of the affected part in
accordance with the applicable service information. The service
information for Model AS332L2 helicopters and the service information
for Model EC225LP helicopters both describe procedures for an
inspection for corrosion and cracking of the attachment pins. However,
the service information for Model AS332L2 helicopters also describes an
inspection of the protective coating of each attachment pin for
scratches and missing protective coating and sanding if necessary; the
service information for Model EC225LP helicopters does not describe
those actions.
Although EASA AD 2018-0172 requires corrective actions if there is
corrosion or cracking of the attachment pins, EASA AD 2018-0172 does
not require any corrective actions if there is any scratch or any
missing protective coating.
This AD requires inspecting the protective coating of each
attachment pin for scratches and missing protective coating, and
sanding if there is any scratch or any missing protective coating, for
all affected helicopters.
EASA AD 2018-0172 requires removing corrosion but does not
provide a corrective action if there are corrosion pits. This AD
requires replacing an attachment pin that has any corrosion pitting.
The service information referenced in EASA AD 2018-0172 specifies
to do a non-destructive inspection if in doubt about whether there is a
crack; that action is not required by this AD.
The service information referenced in EASA AD 2018-0172 specifies
contacting Airbus Helicopters if any attachment pin with a crack is
found and returning that part to Airbus Helicopters; those actions are
not required by this AD.

Costs of Compliance

The FAA estimates that this AD affects 28 helicopters of U.S.
registry. The FAA estimates the following costs to comply with this AD:

Estimated Costs for Required Actions

The FAA estimates the following costs to do any necessary on-
condition measurements (new action), corrosion removal, and
replacements that would be required based on the results of any
required actions. The FAA has no way of determining the number of
helicopters that might need these on-condition measurements, corrosion
removal, and replacements:

Estimated Costs of On-Condition 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:

a. Removing Airworthiness Directive 2017-17-01, Amendment 39-18991 (82
FR 39506, August 21, 2017); and

b. Adding the following new airworthiness directive: