[Federal Register Volume 86, Number 43 (Monday, March 8, 2021)]
[Rules and Regulations]
[Pages 13162-13165]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-03656]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0682; Product Identifier 2017-SW-028-AD; Amendment 
39-21433; AD 2021-04-12]
RIN 2120-AA64


Airworthiness Directives; Robinson Helicopter Company Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
Robinson Helicopter Company (Robinson) Model R66 helicopters. This AD 
was prompted by reports of tail rotor (T/R) drive shaft forward hanger 
bearing failures. This AD requires installing a certain part numbered 
kit and removing parts from service or replacing a certain part-
numbered T/R drive shaft assembly. This AD also prohibits the 
installation of certain parts. The FAA is

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issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective April 12, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain document listed in this AD as of April 12, 2021.

ADDRESSES: For service information identified in this final rule, 
contact Robinson Helicopter Company, 2901 Airport Drive, Torrance, CA 
90505; telephone 310-539-0508; fax 310-539-5198; or at https://robinsonheli.com/technical-support/. You may view a copy of the 
referenced service information at the FAA, Office of the Regional 
Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort 
Worth, TX 76177.

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-2017-
0682; 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 AD, 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: Danny Nguyen, Aerospace Engineer, Los 
Angeles ACO Branch, FAA, 3960 Paramount Blvd., Lakewood, California 
90712; telephone 562-627-5247; email [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a supplemental notice of proposed rulemaking (SNPRM) 
to amend 14 CFR part 39 by adding an AD that would apply to Robinson 
Model R66 helicopters with a T/R drive shaft assembly part number (P/N) 
D224-3 without B900-11 modification installed. The SNPRM published in 
the Federal Register on July 28, 2020 (85 FR 45360). The FAA preceded 
the SNPRM with a notice of proposed rulemaking (NPRM) that published in 
the Federal Register on March 30, 2018 (83 FR 13706). The NPRM was 
prompted by two incidents of forward hanger bearing failure of the T/R 
drive shaft assembly because the bearing was undersized for its 
housing. Consequently, the bearing was spinning at a speed that caused 
excessive heating of the bearing during operation and led to the 
breakdown of the bearing's grease and ultimately seizure of the C647-16 
bearing.
    To correct this condition, Robinson initially issued R66 Service 
Bulletin SB-14, dated June 25, 2015 (SB-14), for certain serial-
numbered helicopters, which specified installing a temperature recorder 
on the T/R drive shaft forward hanger bearing assembly and inspecting 
the temperature recorder during preflight checks and during each 100-
hour inspection. If the bearing was found running hot, then Robinson 
advised upgrading the bearing to a newer design.
    Following additional reports of overheating forward hanger bearing 
assemblies, Robinson superseded SB-14 with R66 Service Bulletin SB-20, 
dated November 7, 2016 (SB-20), which affected additional serial-
numbered helicopters and specified modifying T/R drive shaft assembly 
P/Ns D224-3 and D224-4 by using kit Robinson KI-235 R66 TRDS Forward 
Yoke Assembly and Hanger Installation Kit Instructions, Revision A, 
dated June 23, 2015 (KI-235) and installing yoke assembly P/N D224-5. 
This installation has an improved, larger bearing that spins with less 
friction. SB-20 also specified inspecting the forward and aft sides of 
the hanger and damper bearings for a minimum of 0.5 inch in length of 
sealant on the junction of the black seal and bearing outer race and 
applying sealant if there was less than 0.5 inch in length of sealant.
    Robinson revised SB-20 with R66 Service Bulletin SB-20A, dated June 
6, 2017 (SB-20A), to clarify that helicopters with either T/R drive 
shaft assembly P/N D224-3 with modification B900-11 or P/N D224-4 
installed include the upgraded bearing and do not require kit KI-235.
    Robinson later revised SB-20A with R66 Service Bulletin SB-20B, 
dated December 20, 2017 (SB-20B), which updates writing practices and 
organizes the procedures into two separate sections, clarifies the 
``Rotorcraft Affected'' section, and reduces the helicopters that need 
to perform the inspection and sealant application procedures to just 
helicopters without the latest version damper and housing bearings.
    The NPRM proposed to require within 100 hours time-in-service (TIS) 
replacing an affected T/R drive shaft forward yoke assembly with T/R 
drive shaft yoke assembly P/N D224-5. The NPRM proposed to require 
inspections of the forward and aft sides of the hanger bearing and the 
damper bearing for sealant, and depending on the results of the 
inspections applying sealant. The SNPRM proposed to revise the NPRM by 
expanding the applicability, changing the proposed requirements, and 
correcting nomenclature. The FAA is issuing this AD to address the 
unsafe condition on these products.

Comments

    The FAA gave the public the opportunity to comment on the proposed 
rulemaking. The following presents the comments received on the SNPRM 
and the FAA's response to each comment.
    Request: Robinson requested the FAA change the note to the 
Applicability paragraph to identify certain serial-numbered helicopters 
that had T/R drive shaft assembly P/N D224-4 installed during 
production and clarify that these helicopters are not affected by this 
AD. Robinson explained that the specified serial-numbered helicopters 
with T/R drive shaft assembly P/N D224-4 installed have the larger 
(hanger) bearing, which is not affected by this AD, and clarified that 
P/N D224-5 is a sub-assembly upgrade to P/N D224-4.
    FAA Response: The FAA agrees and has revised that note in this 
final rule to identify the serial-numbered helicopters with T/R drive 
shaft assembly P/N D224-4 installed during production and clarify that 
this part-numbered T/R drive shaft assembly is not affected by this AD.
    Request: Robinson requested that the FAA change the exception in 
paragraph (e)(1)(i) of this AD about not requiring the discarding of 
removed nuts and palnuts and stated that exception implies that the 
nuts and palnuts may be reused. Robinson explained that FAA Advisory 
Circular (AC) 43.13-1B Section 7-122 (d) specifies that these nuts 
should be discarded and referenced Robinson service information that 
specifies upgrading certain nuts any time maintenance is done. Robinson 
also stated that the KI-235 kit includes all required nuts and palnuts 
to replace discarded hardware.
    FAA Response: The FAA disagrees. The FAA cannot require discarding 
of parts in an AD. Paragraph (d), section 7-122, of FAA AC 43.13-1B 
states that the removed nuts should never be reused and should be 
replaced with new ones when removed. Accordingly, the FAA has added 
language to the exception stating that this AD requires removing the 
affected parts from service.

FAA's Determination

    The FAA has reviewed the relevant information, considered the 
comments received, and determined that an unsafe condition exists and 
is likely to exist or

[[Page 13164]]

develop on other products of the same type design and that air safety 
and the public interest require adopting the AD requirements as 
proposed with the changes described previously. These changes are 
consistent with the intent proposed in the SNPRM for correcting the 
unsafe condition and will neither increase the economic burden on any 
operator nor increase the scope of the AD.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed KI-235. This service information provides 
instructions for installing the newly designed yoke assembly, P/N D224-
5.
    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.

Related Service Information

    The FAA has reviewed SB-14, which specifies installing a 
temperature recorder on the T/R drive shaft forward hanger bearing 
assembly and inspecting the temperature during preflight checks and 
during each 100-hour inspection. If the temperature of the bearing is 
found running hot, then Robinson advises upgrading the bearing to a 
newer design (kit P/N KI-235). This service information also specifies 
adding a caution page to the Pilot Operating Handbook regarding the 
overheating bearing assemblies. This service information was superseded 
by SB-20.
    The FAA has reviewed SB-20, SB-20A, and SB-20B, which specify 
upgrading the forward hangar bearing assembly of certain T/R drive 
shaft assemblies to the newer design with kit P/N KI-235 if not 
previously done. For certain installations, this service information 
contains procedures for inspecting for sealant and applying sealant to 
the damper and hanger bearings if needed to prevent seal rotation. This 
service information also specifies removing the caution page from the 
Pilot Operating Handbook regarding the overheating bearing assemblies 
that was added by SB-14.

Differences Between This AD and the Service Information

    SB-20 specifies replacing the yoke assembly and applying sealant to 
the bearing seals within the next 100 flight hours or by January 31, 
2017, whichever comes first, and SB-20A and SB-20B continue the 
compliance time of no later than January 31, 2017. This AD does not 
have a calendar time compliance requirement. SB-20, SB- 20A, and SB-20B 
specify inspecting for sealant and applying sealant to the damper and 
hanger bearings if needed, while this AD does not.

Costs of Compliance

    The FAA estimates that this AD affects 290 helicopters of U.S. 
Registry. The FAA estimates that operators may incur the following 
costs in order to comply with this AD. Labor costs are estimated at $85 
per work-hour.
    Installing Robinson field kit KI-235 takes about 6 work-hours and 
parts cost about $950, for an estimated cost of $1,460 per helicopter. 
As an option, replacing an affected T/R drive shaft assembly P/N D224-3 
with T/R drive shaft assembly P/N D224-4 takes about 5 work-hours and 
parts cost about $4,400, for an estimated cost of $4,825 per 
helicopter.

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 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, 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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2021-04-12 Robinson Helicopter Company: Amendment 39-21433; Docket 
No. FAA-2017-0682; Product Identifier 2017-SW-028-AD.

(a) Applicability

    This airworthiness directive (AD) applies to Robinson Helicopter 
Company (Robinson) Model R66 helicopters, certificated in any 
category, with a tail rotor (T/R) drive shaft assembly part number 
(P/N) D224-3 without B900-11 modification installed.

    Note 1 to paragraph (a): Helicopters with serial number (S/N) 
0631 and subsequent had T/R drive shaft assembly P/N D224-4 
installed during production, which is not affected by this AD.

(b) Unsafe Condition

    This AD defines the unsafe condition as failure of a T/R drive 
shaft forward hanger bearing. This condition could result in failure 
of the T/R drive shaft and subsequent loss of helicopter control.

(c) Effective Date

    This AD is effective April 12, 2021.

(d) Compliance

    You are responsible for performing each action required by this 
AD within the specified compliance time unless it has already been 
accomplished prior to that time.

 (e) Required Actions

    (1) Within 100 hours time-in-service, do one of the following:
    (i) Install Robinson kit P/N KI-235 using KI-235 R66 TRDS 
Forward Yoke Assembly and Hanger Installation Kit Instructions, 
Revision A, dated June 23, 2015, except where the service 
information specifies discarding parts, you are required to remove 
those parts from service instead.
    (ii) Replace the entire T/R drive shaft assembly with T/R drive 
shaft assembly P/N D224-4.
    (2) As of the effective date of this AD, do not install a T/R 
drive shaft assembly P/N D224-3 without B900-11 modification on any 
helicopter.

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(f) Alternative Methods of Compliance (AMOC)

    (1) The Manager, Los Angeles ACO Branch, FAA, may approve AMOCs 
for this AD. Send your proposal to: Danny Nguyen, Aerospace 
Engineer, Los Angeles ACO Branch, FAA, 3960 Paramount Blvd., 
Lakewood, California 90712; telephone 562-627-5247; email [email protected].
    (2) For operations conducted under a 14 CFR part 119 operating 
certificate or under 14 CFR part 91, subpart K, the FAA suggests 
that you notify your principal inspector, or lacking a principal 
inspector, the manager of the local flight standards district office 
or certificate holding district office before operating any aircraft 
complying with this AD through an AMOC.

(g) Related Information

    For service information identified in this AD, contact Robinson 
Helicopter Company, 2901 Airport Drive, Torrance, CA 90505; 
telephone 310-539-0508; fax 310-539-5198; or at https://www.robinsonheli.com. You may view a copy of the service information 
at the FAA, Office of the Regional Counsel, Southwest Region, 10101 
Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177.

(h) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Robinson KI-235 R66 TRDS Forward Yoke Assembly and Hanger 
Installation Kit Instructions, Revision A, dated June 23, 2015.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
Robinson Helicopter Company, 2901 Airport Drive, Torrance, CA 90505; 
telephone 310-539-0508; fax 310-539-5198; or at https://www.robinsonheli.com.
    (4) 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

(i) Subject

    Joint Aircraft Service Component (JASC) Code: 6510, Tail Rotor 
Drive Shaft.

    Issued on February 8, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-03656 Filed 3-5-21; 8:45 am]
BILLING CODE 4910-13-P