DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0727; Project Identifier AD-2021-00835-R;
Amendment 39-21726; AD 2021-19-08]
Airworthiness Directives; Robinson Helicopter Company Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
certain Robinson Helicopter Company Model R44 and R44 II helicopters.
This AD was prompted by reports of cracked tail rotor blades (blades).
This AD requires checking each blade for any crack and removing any
cracked blade from service. This AD also requires removing all affected
blades from service and prohibits installing any affected blade on any
helicopter. The FAA is issuing this AD to address the unsafe condition
on these products.
DATES: This AD is effective September 22, 2021.
The FAA must receive comments on this AD by October 22, 2021.
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
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.
For service information identified in this final rule, contact
Robinson Helicopter Company, Pete Riedl, 2901 Airport Drive, Torrance,
CA 90505, United States; phone: (310) 539-0508; email:
firstname.lastname@example.org; website: https://robinsonheli.com/. 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.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0727; 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 street address for the
Docket Operations is listed above.
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 email@example.com.
The FAA received reports of spanwise cracks found along the leading
edge of part number (P/N) C029-3 blades, serial numbers (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 is a manufacturing defect in the properties of the blade skin
that makes the blades prone to stress corrosion cracking. This
condition, if not addressed, could result in reduced controllability
and subsequent loss of control of the helicopter. The FAA is issuing
this AD to address the unsafe condition on these products.
The FAA is issuing this AD because the agency has determined the
unsafe condition described previously is likely to exist or develop in
other products of the same type design.
Related Service Information
The FAA reviewed Robinson Helicopter Company 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.
This AD requires, before further flight and thereafter before each
flight, checking blade P/N C029-3 with S/N 9410 through 9909 inclusive,
for any crack along the leading edge of the blade. An owner/operator
(pilot) may perform this required check but must enter compliance with
the applicable paragraph of this AD in the helicopter maintenance
records in accordance with 14 CFR 43.9(a)(1) through (4) and
91.417(a)(2)(v). A pilot may perform this check because it involves
visually checking each blade for a crack. This action can be performed
equally well by a pilot or a mechanic. This check is an exception to
the FAA's standard maintenance regulations. This AD also requires,
before further flight, removing from service any cracked blade and
prohibits installing the affected blades on any helicopter.
Additionally, this AD requires, within three months after the effective
date of this AD, removing all affected blades from service.
Justification for Immediate Adoption and Determination of the Effective
Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and
comment procedures for rules when the agency, for ``good cause,'' finds
that those procedures are ``impracticable, unnecessary, or contrary to
interest.'' Under this section, an agency, upon finding good cause, may
issue a final rule without providing notice and seeking comment prior
to issuance. Further, section 553(d) of the APA authorizes agencies to
make rules effective in less than thirty days, upon a finding of good
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies foregoing notice and comment prior to adoption of this rule
because an urgent unsafe condition exist and corrective actions must
accomplished before further flight and then within three months.
Accordingly, notice and opportunity for prior public comment are
impracticable and contrary to the public interest pursuant to 5 U.S.C.
In addition, the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days,
for the same reasons the FAA found good cause to forego notice and
The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
ADDRESSES. Include ``Docket No. 2021-0727 and Project Identifier AD-
2021-00835-R'' at the beginning of your comments. The most helpful
comments reference a specific portion of the final rule, 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 final rule 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 final rule.
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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to 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 firstname.lastname@example.org.
Any commentary that the FAA receives which is not specifically
designated as CBI will be placed in the public docket for this
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because FAA has determined
that it has good cause to adopt this rule without prior notice and
comment, RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 164 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 the tail rotor
blade for any crack takes about 0.25 work-hour for an estimated cost of
$22 per inspection. Replacing the tail rotor blade takes about 3.5
work-hours and parts cost about $3,320 for an estimated cost of $3,618
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
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
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, and
(2) Will not affect intrastate aviation in Alaska.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
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