DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0872; Project Identifier AD-2022-00431-R;
Amendment 39-22181; AD 2022-19-12]
RIN 2120-AA64

Airworthiness Directives; Robinson Helicopter Company Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2021-19-
08, which applied to certain Robinson Helicopter Company (Robinson)
Model R44 and R44 II helicopters. AD 2021-19-08 required checking each
tail rotor blade (blade) for any crack and removing any cracked blade
from service. AD 2021-19-08 also required removing all affected blades
from service and prohibited installing any affected blade on any
helicopter. Since the FAA issued AD 2021-19-08, it was determined that
an additional model helicopter and additional blades are affected by
the unsafe condition. This AD requires the same actions as AD 2021-19-
08 and adds certain Robinson Model R66 helicopters to the applicability
and adds additional part-numbered and serial-numbered blades to the
applicability. The FAA is issuing this AD to address the unsafe
condition on these products.

DATES: This AD is effective October 20, 2022.

ADDRESSES: AD Docket: You may examine the AD docket at regulations.gov
by searching for and locating Docket No. FAA-2022-0872; 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: James Guo, Aerospace Engineer,
Airframe Section, Los Angeles ACO Branch, Compliance & Airworthiness
Division, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; telephone
(562) 627-5357; email james.guo@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2021-19-08, Amendment 39-21726 (86 FR
49915, September 7, 2021) (AD 2021-19-08). AD 2021-19-08 applied to
Robinson Model R44 and R44 II helicopters with a blade part number (P/
N) C029-3 with serial number (S/N) 9410 through 9909 inclusive,
installed. The NPRM published in the Federal Register on July 13, 2022
(87 FR 41627). The NPRM was prompted by reports of spanwise cracks
found along the leading edge of P/N C029-3 blades, S/N 9410 through
9909. These affected blades were factory-installed or shipped as spares
between March and December 2019. The cracks were found at different
inspection intervals ranging from preflight inspections to 100-hour
inspections. In one instance, a cracked blade was suspected when the
pilot felt abnormal vibrations during flight; subsequent investigation
determined that the blade was cracked. The cause of the cracks was
determined to be a manufacturing defect in the properties of the blade
skin that makes the blades prone to stress corrosion cracking. The NPRM
was also prompted by a determination after AD 2021-19-08 was issued
that an additional model helicopter and additional blades are affected
by the unsafe condition. This condition, if not addressed, could result
in reduced controllability and subsequent loss of control of the
helicopter. AD 2021-19-08 required checking each blade for any crack and
removing any cracked blade from service. AD 2021-19-08 also required removing
all affected blades from service and prohibited installing any affected blade on any
helicopter. In the NPRM, the FAA proposed to continue to require, before further
flight and thereafter before each flight, checking each affected blade
for any crack along the leading edge of the blade. An owner/operator
(pilot) holding at least a private pilot certificate may perform this
check and would have to enter compliance with the applicable paragraph
of this AD in the helicopter maintenance records in accordance with 14
CFR 43.9(a) and 91.417(a)(2)(v). A pilot may perform this check because
it involves visually checking each blade for a crack. This action could
be performed equally well by a pilot or a mechanic. This check is an
exception to the FAA's standard maintenance regulations. The NPRM also
proposed to continue to require, before further flight, removing from
service any cracked blade and prohibit installing the affected blades
on any helicopter. This NPRM also proposed to require, within three
months after the effective date of AD 2021-19-08 or within six months
after the effective date of this AD, as applicable, removing all
affected blades from service. Finally, the NPRM revises the
applicability of AD 2021-19-08 by adding blades with P/N C029-3 with S/
N 9910 through 10659 inclusive to the applicability for Robinson Model
R44 and R44 II helicopters and also expands the applicability of AD
2021-19-08 by adding Robinson Model R66 helicopters with blade P/N F-
029-1 with S/N 2410 through 2589 inclusive installed.

Discussion of Final Airworthiness Directive

Comments

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

Conclusion

The FAA reviewed the relevant data and determined that air safety
requires adoption of the AD as proposed. Accordingly, the FAA is
issuing this AD to address the unsafe condition on these products.
Except for minor editorial changes, this AD is adopted as proposed in
the NPRM.

Related Service Information

The FAA reviewed Robinson R44 Service Bulletin SB-108, dated June
30, 2021. This service bulletin specifies removing P/N C029-3 blades
with S/N 9410 through 9909 from service. For continued operation until
the affected blades are replaced, the service bulletin specifies a
preflight inspection to be performed by the pilot.
The FAA also reviewed Robinson R44 Service Bulletin SB-110, which
specifies removing P/N C029-3 blades with S/N 9910 through 10659 from
service and Robinson R66 Service Bulletin SB-40, which specifies
removing P/N F029-1 blades with S/N 2410 through 2589 from service.
Both of these service bulletins are dated January 6, 2022, and specify
that a preflight inspection is to be performed by the pilot for
continued operation until the affected blades are replaced.

Costs of Compliance

The FAA estimates that this AD affects 432 helicopters of U.S.
registry. The FAA estimates the following costs to comply with this AD.
Labor costs are estimated at $85 per work-hour.
Checking a blade for any crack takes about 0.25 work-hour for an
estimated cost of up to $44 per helicopter (up to two affected blades
per helicopter) and up to $19,008 for the U.S. fleet per check.
Replacing a blade takes about 3.5 work-hours and parts cost about
$3,320 for an estimated cost of $3,618 per blade and up to $3,125,952
for the U.S. fleet.
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 products identified in this rulemaking action.

Regulatory Findings

The FAA has determined that 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:

a. Removing Airworthiness Directive 2021-19-08, Amendment 39-21726 (86
FR 49915, September 7, 2021); and

b. Adding the following new airworthiness directive: