[Federal Register Volume 86, Number 154 (Friday, August 13, 2021)]
[Proposed Rules]
[Pages 44652-44655]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-17032]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0653; Project Identifier AD-2021-00170-R]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters Inc. (MDHI) Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for MD Helicopters Inc. (MDHI), Model 369D, 369E, 369F, 369FF, 369H, 
369HE, 369HM, 369HS, 500N, and 600N helicopters. This proposed AD was 
prompted by a report of a spiral crack in the pilot-to-copilot tail 
rotor torque tube (torque tube). This proposed AD would require a one-
time visual and recurring borescope inspections of the torque tube and 
depending on the results, removing the torque tube from service. The 
FAA is proposing this AD to address the unsafe condition on these 
products.

DATES: The FAA must receive comments on this proposed AD by September 
27, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions 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 between 9 a.m. and 
5 p.m.,

[[Page 44653]]

Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact MD 
Helicopters, Inc., Attn: Customer Support Division, 4555 E McDowell 
Rd., Mail Stop M615, Mesa, AZ 85215-9734; telephone (800) 388-3378; fax 
(480) 346-6813; or at https://www.mdhelicopters.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-2021-0653; 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 NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Payman Soltani, Aerospace Engineer, 
Airframe Section, Los Angeles ACO Branch, Compliance & Airworthiness 
Division, FAA, 3960 Paramount Blvd., Lakewood, CA 90712; telephone 
(562) 627-5313; email payman.soltani@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0653; Project Identifier 
AD-2021-00170-R'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, 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 proposal 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 NPRM.

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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to 
Payman Soltani, Aerospace Engineer, Airframe Section, Los Angeles ACO 
Branch, Compliance & Airworthiness Division, FAA, 3960 Paramount Blvd., 
Lakewood, CA 90712; telephone (562) 627-5313; email 
payman.soltani@faa.gov. Any commentary that the FAA receives which is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.

Background

    The FAA proposes to adopt a new AD for MDHI Model 369D, 369E, 369F, 
369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This 
proposed AD would require a one-time visual and recurring borescope 
inspections of the torque tube and depending on the results, removing 
the torque tube from service. This proposed AD was prompted by a report 
of a spiral crack in the torque tube that appears to have originated 
from a hole where the tail rotor torque tube control fitting attaches 
to the torque tube on a Model 369FF helicopter. This crack resulted in 
increased left pedal movement and subsequent reduced directional 
control pedal authority. Other model helicopters are affected due to 
design similarity. This condition, if not addressed, could result in 
failure of the torque tube, loss of tail rotor control, and subsequent 
loss of control of the helicopter.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of these same type designs.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed MD Helicopters Service Bulletin SB369D-229R2 for 
Model 369D helicopters, SB369E-129R2 for Model 369E helicopters, 
SB369F-119R2 for Model 369F and 369FF helicopters, SB369H-263R2 for 
Model 369H, 369HE, 369HM, and 369HS helicopters, SB500N-066R2 for Model 
500N helicopters, and SB600N-080R2 for Model 600N helicopters, each 
dated March 24, 2021 (Revision 2). These service bulletins are co-
published as one document. Revision 2 of this service information 
specifies procedures for a one-time visual inspection and recurring 
borescope inspections, completing a Service Operation Report, and 
returning a removed torque tube to an authorized service center or 
MDHI.

Other Related Service Information

    The FAA also reviewed MD Helicopters Service Bulletin SB369H-263, 
SB369D-229, SB369E-129, SB369F-119, SB500N-066, and SB600N-080, each 
dated January 30, 2020 (initial issuance), and MD Helicopters Service 
Bulletin SB369H-263R1, SB369D-229R1, SB369E-129R1, SB369F-119R1, 
SB500N-066R1, and SB600N-080R1, each dated May, 15 2020 (Revision 1). 
The initial issuance and Revision 1 of this service information specify 
the same procedures as Revision 2 of this service information, except 
Revision 1 clarified the torque value to apply to the nut and Revision 
2 deletes Method 2 of the Accomplishment Instructions and adds a 
recurring 300-hour borescope inspection of the torque tube.

Proposed AD Requirements in This NPRM

    This proposed AD would initially require visually inspecting the 
torque tube exterior using a flashlight and mirror and borescope 
inspecting the interface of the torque tube and bushing segments for a 
crack, elongation, and other damage, which may be indicated by any 
corrosion, pitting, crazing, dents, dings, displacement of material at 
the bolt hole edge, or fretting of the hole. Thereafter, this proposed 
AD would require repeating the borescope inspection. If there is a 
crack, elongation, or other damage, this proposed AD would require 
removing the torque tube from service.

Differences Between This Proposed AD and the Service Information

    For helicopters that have accumulated 600 or less total hours time-
in-service (TIS), Revision 2 of the service information specifies an 
initial compliance time of during the next 100-hour inspection, whereas 
this proposed AD would require initial actions within 100 hours TIS 
after the effective date of this AD instead. For helicopters that have 
accumulated more than 600 total

[[Page 44654]]

hours TIS, Revision 2 of the service information specifies initial a 
compliance time of within 5 hours of flight time, whereas this proposed 
AD would require initial actions within 5 hours TIS or 30 days after 
the effective date of this AD, whichever occurs later, instead.
    Revision 2 of the service information specifies returning a removed 
torque tube, whereas this proposed AD would require removing the torque 
tube from service instead. Revision 2 of the service information 
specifies completing a Service Operation Report, whereas this proposed 
AD does not include that requirement.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 58 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 proposed AD.
    Visually inspecting the torque tube would take a minimal amount of 
time. Borescope inspecting the torque tube would take about 1 work-hour 
for an estimated cost of $85 per helicopter and $4,930 for the U.S. 
fleet, per inspection cycle.
    If required, replacing the torque tube would take about 5 work-
hours and parts would cost about $983 for an estimated cost of $1,408 
per helicopter.
    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some of the costs of this 
proposed 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 determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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:

MD Helicopters Inc. (MDHI): Docket No. FAA-2021-0653; Project 
Identifier AD-2021-00170-R.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 27, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to MD Helicopters Inc. (MDHI) Model 369D, 369E, 
369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, 
certificated in any category, with pilot-to-copilot tail rotor 
torque tube (torque tube) part number 369H7531-9/-11/-13, installed.

(d) Subject

    Joint Aircraft Service Component (JASC) Code: 6720, Tail Rotor 
Control System.

(e) Unsafe Condition

    This AD was prompted by a report of a spiral crack in the torque 
tube. The FAA is issuing this AD to prevent failure of a torque 
tube. The unsafe condition, if not addressed, could result in loss 
of tail rotor control and subsequent loss of control of the 
helicopter.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) Using a flashlight and mirror, visually inspect the exterior 
of the torque tube at the interface of the torque tube and bushing 
segments, and borescope inspect the interior of the torque tube at 
the interface of the torque tube and bushing segments for a crack, 
elongation, and other damage, which may be indicated by any 
corrosion, pitting, crazing, dents, dings, displacement of material 
at the bolt hole edge, or fretting of the hole by following the 
Accomplishment Instructions, paragraphs 2.A.(1). through (3).(a)., 
of MD Helicopters Service Bulletin SB369H-263R2, SB369D-229R2, 
SB369E-129R2, SB369F-119R2, SB500N-066R2, or SB600N-080R2, each 
dated March 24, 2021, as applicable to your model helicopter, as 
follows:
    Note 1 to paragraph (g)(1): Scaling of the inner diameter primer 
or paint may be an indication of a crack.
    (i) For helicopters that have accumulated 600 or less total 
hours time-in-service (TIS), within 100 hours TIS after the 
effective date of this AD.
    (ii) For helicopters that have accumulated more than 600 total 
hours TIS, within 5 hours TIS or 30 days after the effective date of 
this AD, whichever occurs later.
    Note 2 to paragraph (g)(1)(ii): It is advised to limit flights 
with increased, excessive, or rapid pedal movements before the first 
instance of the actions required by paragraph (g)(1)(ii) are 
accomplished.
    (iii) If there is a crack, elongation, or other damage, before 
further flight, remove the torque tube from service.
    (2) Thereafter following paragraph (g)(1) of this AD, at 
intervals not to exceed 300 hours TIS, borescope inspect the 
interior of the torque tube at the interface of the torque tube and 
bushing segments as required by paragraph (g)(1) of this AD. If 
there is a crack, elongation, or other damage, before further 
flight, remove the torque tube from service.

(h) Credit for Previous Actions

    You may take credit for the instance of the actions required by 
paragraphs (g)(1)(i) or (ii) of this AD if you performed 
corresponding actions before the effective date of this AD using MD 
Helicopters Service Bulletin SB369H-263, SB369D-229, SB369E-129, 
SB369F-119, SB500N-066, or SB600N-080, each dated January 30, 2020, 
as applicable to your model helicopter, or MD Helicopters Service 
Bulletin SB369H-263R1, SB369D-229R1, SB369E-129R1, SB369F-119R1, 
SB500N-066R1, or SB600N-080R1, each dated May, 15 2020, as 
applicable to your model helicopter.

[[Page 44655]]

(i) No Reporting Requirement

    Although MD Helicopters Service Bulletin SB369H-263R2, SB369D-
229R2, SB369E-129R2, SB369F-119R2, SB500N-066R2, and SB600N-080R2, 
each dated March 24, 2021, specify to submit certain information to 
the manufacturer, this AD does not include that requirement.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles ACO, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, information may be emailed to: 
9-ANM-LAACO-AMOC-REQUESTS@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Related Information

    (1) For more information about this AD, contact Payman Soltani, 
Aerospace Engineer, Airframe Section, Los Angeles ACO Branch, 
Compliance & Airworthiness Division, FAA, 3960 Paramount Blvd., 
Lakewood, CA 90712; telephone (562) 627-5313; email 
payman.soltani@faa.gov.
    (2) For service information identified in this AD, contact MD 
Helicopters, Inc., Attn: Customer Support Division, 4555 E McDowell 
Rd., Mail Stop M615, Mesa, AZ 85215-9734; telephone (800) 388-3378; 
fax (480) 346-6813; or at https://www.mdhelicopters.com. You may 
view this 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.

    Issued on August 2, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-17032 Filed 8-12-21; 8:45 am]
BILLING CODE 4910-13-P


