[Federal Register Volume 86, Number 231 (Monday, December 6, 2021)]
[Rules and Regulations]
[Pages 68884-68886]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-26332]


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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; 
Amendment 39-21784; AD 2021-22-11]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters Inc. (MDHI) 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 
certain MD Helicopters Inc. (MDHI), Model 369D, 369E, 369F, 369FF, 
369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This AD was 
prompted by a report of a spiral crack in the pilot-to-copilot tail 
rotor torque tube (torque tube). This AD requires 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 issuing this 
AD to address the unsafe condition on these products.

DATES: This AD is effective January 10, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of certain documents listed in this AD as of January 10, 
2022.

ADDRESSES: For service information identified in this final rule, 
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. Service Information that is 
incorporated by reference is also available at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
0653.

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 final rule, 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: 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 [email protected].

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 MDHI Model 369D, 369E, 
369F,

[[Page 68885]]

369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, with 
torque tube part number 369H7531-9/-11/-13, installed. The NPRM 
published in the Federal Register on August 13, 2021 (86 FR 44652). In 
the NPRM, the FAA proposed to 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, the NPRM 
proposed to require repeating the borescope inspection. If there is a 
crack, elongation, or other damage, the NPRM proposed to require 
removing the torque tube from service. The NPRM 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.

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 adopting this 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. 
The minor editorial changes include updating the cross reference in 
Note 2 from ``paragraph (g)(1)(ii)'' to ``paragraph (g)(1)(ii) of this 
AD,'' and deleting paragraph ``(i) No Reporting Requirement'' of the 
published NPRM because it is unnecessary. As a result of deleting that 
paragraph, some paragraph identifiers have changed.

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 (co-published as one document and collectively 
referred to as ``Revision 2''). 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.
    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 ADDRESSES.

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 (co-published as one document and collectively 
referred to as ``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 (co-published 
as one document and collectively referred to as ``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.

Differences Between This 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 AD requires initial actions within 100 hours TIS after the 
effective date of this AD instead. For helicopters that have 
accumulated more than 600 total hours TIS, Revision 2 of the service 
information specifies an initial compliance time of within 5 hours of 
flight time, whereas this AD requires 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 AD requires removing the torque tube from 
service instead. Revision 2 of the service information specifies 
completing a Service Operation Report, whereas this AD does not include 
that requirement.

Costs of Compliance

    The FAA estimates that this AD affects 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 AD.
    Visually inspecting the torque tube takes a minimal amount of time. 
Borescope inspecting the torque tube takes 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 takes about 5 work-hours and 
parts 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 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,

[[Page 68886]]

    (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

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:

2021-22-11 MD Helicopters Inc. (MDHI): Amendment 39-21784; Docket 
No. FAA-2021-0653; Project Identifier AD-2021-00170-R.

(a) Effective Date

    This airworthiness directive (AD) is effective January 10, 2022.

(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 the introductory text of 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) of this AD 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.

(i) 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: 
[email protected].
    (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.

(j) 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 
[email protected].
    (2) MD Helicopters Service Bulletin SB369H-263, SB369D-229, 
SB369E-129, SB369F-119, SB500N-066, and SB600N-080, each dated 
January 30, 2020 (co-published as one document and collectively 
referred to as ``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 (co-
published as one document and collectively referred to as ``Revision 
1''), which are not incorporated by reference, contain additional 
information about the subject of this AD. This service information 
is available at the contact information specified in paragraphs 
(k)(3) and (4) of this AD.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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) MD Helicopters Service Bulletin SB369D-229R2, dated March 
24, 2021.
    (ii) MD Helicopters Service Bulletin SB369E-129R2, dated March 
24, 2021.
    (iii) MD Helicopters Service Bulletin SB369F-119R2, dated March 
24, 2021.
    (iv) MD Helicopters Service Bulletin SB369H-263R2, dated March 
24, 2021.
    (v) MD Helicopters Service Bulletin SB500N-066R2, dated March 
24, 2021.
    (vi) MD Helicopters Service Bulletin SB600N-080R2, dated March 
24, 2021.
    Note 3 to paragraph (k)(2): The service bulletins listed in 
paragraphs (k)(2)(i) through (vi) of this AD are co-published as one 
document.
    (3) For MD Helicopters 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.
    (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. For information on the availability of 
this material at the FAA, call (817) 222-5110.
    (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.

    Issued on October 14, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-26332 Filed 12-3-21; 8:45 am]
BILLING CODE 4910-13-P


