DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0463; Project Identifier 2018-SW-050-AD; Amendment
39-21698; AD 2021-17-15]
RIN 2120-AA64

Airworthiness Directives; Leonardo S.p.a. Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
Leonardo S.p.a. Model AB139 and AW139 helicopters with certain main
rotor blades installed. This AD was prompted by a report of an in-
flight loss of a main rotor blade (MRB) tip cap. This AD requires
inspecting the MRB tip cap for disbonding. The FAA is issuing this AD
to address the unsafe condition on these products.

DATES: This AD is effective October 13, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain document listed in this AD as of October 13,
2021.

ADDRESSES: For service information identified in this final rule,
contact Leonardo S.p.A. Helicopters, Emanuele Bufano, Head of
Airworthiness, Viale G.Agusta 520, 21017 C.Costa di Samarate (Va)
Italy; telephone +39-0331-225074; fax +39-0331-229046; or at https://customerportal.leonardocompany.com/en-US/. 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. For information on the availability of this material at the FAA,
call (817) 222-5110. It is also available at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0463.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0463; 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 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: Bang Nguyen, Aerospace Engineer,
Certification Section, Fort Worth ACO Branch, Compliance &
Airworthiness Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX
76177; telephone (817) 222-4973; email bang.nguyen@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to Leonardo S.p.a. Model
AB139 and AW139 helicopters with an MRB that has less than 1,200 total
hours time-in-service (TIS) and has part number (P/N) 3G6210A00131 with
any serial number (S/N) listed in Table 1 of Leonardo Helicopters Alert
Service Bulletin No. 139-520, dated April 26, 2018 (ASB 139-520),
installed. The NPRM published in the Federal Register on June 16, 2021
(86 FR 31992). In the NPRM, the FAA proposed to require, within 50
hours TIS, tap inspecting each MRB tip cap for disbonding using a tap
hammer or equivalent. If there is no disbonding, the NPRM proposed to
require tap inspecting the MRB tip cap at intervals not to exceed 50
hours TIS. If there is any disbonding that does not exceed the
specified limits in ASB 139-520, the NPRM proposed to require tap
inspecting the MRB at intervals not to exceed 10 hours TIS. If there is
any disbonding that exceeds the specified limits in ASB 139-520, the
NPRM proposed to require removing the MRB from service before further
flight. The NPRM also specified that the accumulation of 1,200 total
hours TIS on the affected part without findings of any disbonded area
or with findings of any disbonded area that is within the permitted
limits in Annex A of ASB 139-520 would constitute terminating action
for the proposed repetitive inspections. Finally, the NPRM proposed to
prohibit installing any MRB that is identified in the applicability
section of this AD on any helicopter.
The NPRM was prompted by reports of incorrect bonding procedures on
certain MRBs, which if not detected and corrected, could result in loss
of the MRB tip cap, severe vibrations, and subsequent loss of control
of the helicopter.
The FAA issued AD 2018-03-01, Amendment 39-19174 (83 FR 4136,
January 30, 2018) (AD 2018-03-01) for Agusta S.p.A. (now Leonardo
S.p.a.) Model AB139 and AW139 helicopters with MRB P/N 3G6210A00131
with an S/N 3615, 3634, 3667, or 3729 installed. AD 2018-03-01 requires
inspecting the MRB tip cap for disbonding and was prompted by EASA AD
2017-0175-E, dated September 13, 2017 (EASA AD 2017-0175-E), issued by
EASA, which is the Technical Agent for the Member States of the
European Union. EASA advised of an in-flight loss of an MRB tip cap on
an AW139 helicopter where the pilot was able to safely land the
helicopter. EASA further advised that an investigation determined the
cause as incorrect bonding procedures used during production on MRB P/N
3G6210A00131, S/N 3615, 3634, 3667, and 3729. According to EASA, this
condition could result in loss of an MRB tip cap, increased pilot
workload, and reduced control of the helicopter. To address this unsafe
condition, EASA AD 2017-0175-E requires a one-time inspection of the
affected MRB tip caps within 5 flight hours (FH) and replacing the
affected MRBs within 10 FH if not replaced as a result of the
inspection. EASA AD 2017-0175-E also prohibits installing the affected
MRBs on a helicopter. AD 2018-03-01 requires the same corrective
actions.
After the FAA issued AD 2018-03-01, EASA issued EASA AD 2018-0130,
dated June 18, 2018 (EASA AD 2018-0130), to correct the same unsafe
condition for Leonardo S.p.a. Model AB139 and AW139 helicopters with
additional serial-numbered MRBs installed. EASA advises that further
investigations after EASA AD 2017-0175-E was issued determined that
another batch of P/N 3G6210A00131 MRBs may have been subject to the
incorrect bonding procedure, but to a less critical extent. EASA AD
2018-0130, which neither revises nor supersedes EASA AD 2017-0175-E,
applies to the following serial-numbered MRBs with less than 1,200 FH:
2709, 3558, 3624, 3707, 3790, 3486, 3561, 3625, 3717, 3795, 3488, 3569,
3626, 3720, 3798, 3495, 3570, 3627, 3725, 3803, 3500, 3574, 3628, 3726,
3807, 3501, 3575, 3633, 3734, 3812, 3502, 3582, 3636, 3735, 3822, 3503,
3583, 3638, 3738, 3824, 3508, 3586, 3642, 3739, 3825, 3510, 3590, 3648,
3741, 3827, 3513, 3592, 3649, 3743, 3831, 3520, 3595, 3650, 3744, 3832,
3527, 3597, 3651, 3745, 3838, 3528, 3599, 3657, 3753, 3841, 3529, 3602,
3665, 3754, 3842, 3531, 3603, 3672, 3761, 3847, 3536, 3605, 3682, 3766,
3850, 3539, 3609, 3684, 3770, 3851, 3544, 3612, 3686, 3771, 3852, 3549,
3613, 3690, 3777, 3853, 3551, 3616, 3691, 3783, 3854, 3556, 3620, 3695,
3788, 3855, 3557, 3622, 3696, and 3789.
Accordingly, EASA AD 2018-0130 requires within 50 FH and thereafter
at intervals not to exceed 50 FH, tap inspecting the MRB for
disbonding. If there is disbonding within permitted limits, EASA AD
2018-0130 requires tap inspecting the disbonded area within 10 FH and
thereafter at intervals not to exceed 10 FH. If disbonding that exceeds
the permitted limits is found during any inspection, EASA AD 2018-0130
requires replacing the part. EASA AD 2018-0130 also prohibits
installing the affected part unless it is a serviceable part and
includes a terminating action for the repetitive inspections, which is
accumulation of 1,200 FH by an affected part without findings of
disbonded area, or findings of disbonded area within the limits
specified in Annex A of ASB 139-520.

Discussion of Final Airworthiness Directive

The FAA received no comments on the NPRM or on the determination of
the costs.

Conclusion

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 reviewed the relevant
data and determined that air safety requires adopting this AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these helicopters.

Related Service Information Under 1 CFR Part 51

The FAA reviewed ASB 139-520. This service information specifies
procedures for repetitively inspecting the tip cap on a certain batch
of MRBs for disbonding using a tap test and replacing the MRB if
disbonding is not within permitted limits.
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.

Differences Between This AD and the EASA AD

EASA AD 2018-0130 allows replacing an affected part with a
serviceable part, which is marked with the letter ``R'' (repaired tip
cap) as the last digit of the S/N, as a terminating action for the
repetitive inspections specified in that AD, whereas this AD does not.

Costs of Compliance

The FAA estimates that this AD affects 114 helicopters of U.S.
Registry. Labor rates are estimated at $85 per work-hour. Based on
these numbers, the FAA estimates the following costs to comply with
this AD.
Tap inspecting an MRB tip cap takes 1 work-hour, for a cost per
helicopter of $85 per inspection cycle for a total U.S. fleet cost of
$9,690 per inspection cycle. Replacing 1 MRB, if required, takes 4
work-hours, and required parts cost $141,725, for a total cost of
$142,065 per MRB.
The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some of the costs of this AD
may be covered under warranty, thereby reducing the cost impact on
affected operators.

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.

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: