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PROPOSED AD BELL TEXTRON CANADA LIMITED: Docket No. FAA-2021-1074; Project Identifier MCAI-2021-00447-R.
(a) COMMENTS DUE DATE

    The FAA must receive comments on this  airworthiness directive (AD) by
    February 7, 2022.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to Bell Textron Canada Limited Model 429  helicopters,
    serial  numbers  (S/N)  57001  and  subsequent,  certificated  in  any
    category.

(d) SUBJECT

    Joint Aircraft  Service Component  (JASC) Code:  5302, Rotorcraft tail
    boom.

(e) UNSAFE CONDITION

    This AD was prompted by reports of failed rivets between the  tailboom
    skin and  the tail  rotor (TR)  gearbox support  assembly. The  FAA is
    issuing this  AD to  detect failed  rivets and  rivets with inadequate
    grip length. The unsafe condition,  if not addressed, could result  in
    deterioration of the joint structural integrity, detachment  of the TR
    gearbox support assembly, and loss of helicopter control.

(f) COMPLIANCE

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

(g) REQUIRED ACTIONS

(1) As of  the effective date  of this AD,  for Model 429  helicopters S/N
    57002 through 57210 inclusive and  S/N 57212 and subsequent that  have
    accumulated less  than 300  total hours  time-in-service (TIS), before
    accumulating 400  total hours  TIS; or  for Model  429 helicopters S/N
    57002 through 57210 inclusive and  S/N 57212 and subsequent that  have
    replaced the  TR gearbox  support assembly  part number  (P/N) 429-034
    -701-101 or  P/N 429-035-705-101  and the  helicopter has  accumulated
    less than 300 total hours TIS since the replacement of the TR  gearbox
    support assembly, before  accumulating 400 total  hours TIS since  the
    replacement:

(i) Visually  inspect  the  external  surface of  the  TR gearbox  support
    assembly for any rivet heads  that have separated from their  tail. If
    there are any rivet heads that have separated from their tail,  before
    further  flight,  measure  any gaps  between  the  TR gearbox  support
    assembly  and  the  tailboom  skin  by  following  the  Accomplishment
    Instructions,  Part  I,  paragraphs 9.b.  through  9.d  of Bell  Alert
    Service Bulletin 429-19-47,  Revision B, dated  January 27, 2021  (ASB
    429-19-47 Rev B).

(A) If there are no gaps or if any gap measures less than 0.005 in  (0.127
    mm), before further flight, remove the rivets from service.

(B) If there are any gaps that are equal to or exceed 0.005 in (0.127 mm),
    before  further flight,  repair the  gaps in  accordance with  an FAA-
    approved method, and remove the rivets from service.

(ii) Borescope  inspect  or use  a light  source  and  mirror to  visually
     inspect each rivet inside the  tailboom for any missing rivet  tails,
     any rivet tails resting at the bottom of the tailboom, and any  rivet
     tails not resting against the tailboom skin.

(A) If there are  any missing rivet tails,  or any rivet tails  resting at
    the bottom of  the tailboom, before  further flight, measure  any gaps
    between  the TR  gearbox support  assembly and  the tailboom  skin  by
    following  the Accomplishment  Instructions, Part  I, paragraphs  9.b.
    through 9.d of ASB 429-19-47 Rev B, and perform the corrective actions
    specified in paragraphs (g)(1)(i)(A) or (B) of this  AD as applicable.

(B) If there  are any rivet  tails not resting  against the tailboom  skin
    before further flight, remove the rivets from service.

(iii) Perform a tactile inspection of the rivets identified in Figure 1 of
      ASB 429-19-47 Rev B,  by pulling on each  rivet tail with pliers  or
      pulling by hand.  If any rivet  does not come  out when pulled  with
      pliers or  when pulled  by hand,  before further  flight, remove the
      rivet from service.

(2) For Model  429 helicopters S/N  57002 through 57210  inclusive and S/N
    57212 and subsequent  that are not  identified in paragraph  (g)(1) of
    this AD, within  100 hours TIS  after the effective  date of this  AD,
    perform the actions as specified in paragraph (g)(1)(i) through  (iii)
    of this AD.

(3) For Model  429 helicopters S/N  57002 through 57210  inclusive and S/N
    57212  and  subsequent,  within  400  hours  TIS  after  the   initial
    inspections  required  by  paragraph  (g)(1) or  (2)  of  this  AD, as
    applicable  to your  helicopter, and  thereafter at  intervals not  to
    exceed 400 hours  TIS, accomplish the  actions required by  paragraphs
    (g)(1)(i) through (iii) of this AD.

(4) For Model 429  helicopters S/N 57001 and  57211, within 400 hours  TIS
    after the effective date of  this AD, and thereafter at  intervals not
    to exceed 400 hours TIS, accomplish the actions required by paragraphs
    (g)(1)(i) through (iii) of this AD.

(h) CREDIT FOR PREVIOUS ACTIONS

    This paragraph provides credit for the actions specified in paragraphs
    (g)(1) and (2) of this AD, if those actions were performed before  the
    effective date of this AD using Bell Alert Service Bulletin 429-19-47,
    Revision A,  dated November  2, 2020,  or Bell  Alert Service Bulletin
    429-19-47, dated August 28, 2019.

(i) ALTERNATIVE METHODS OF COMPLIANCE (AMOCS)

(1) The Manager, International  Validation Branch, 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
    International  Validation  Branch, send  it  to the  attention  of the
    person identified in paragraph (j)(1)  of this AD. Information may  be
    emailed to: 9-AVS-AIR-730-AMOC@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.

(j) RELATED INFORMATION

(1) For more information about this AD, contact Andrea Jimenez,  Aerospace
    Engineer, COS Program  Management Section, Operational  Safety Branch,
    Compliance &  Airworthiness Division,  FAA, 1600  Stewart Ave.,  Suite
    410,   Westbury,   NY   11590;   telephone   (516)   228-7330;   email
    andrea.jimenez@faa.gov.

(2) For service  information identified in  this AD, contact  Bell Textron
    Canada  Limited,  12,800 Rue  de  l'Avenir, Mirabel,  Quebec  J7J 1R4,
    Canada;  telephone  1-450-437-2862  or  1-800-363-8023;  fax 1-450-433
    -0272;      email      productsupport@bellflight.com;      or       at
    https://www.bellflight.com/support/contact-support. 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.

(3) The subject of this AD is addressed in Transport Canada AD CF-2021-15,
    dated April  14, 2021.  You may  view the  Transport Canada  AD on the
    internet at https://www.regulations.gov in Docket No. FAA-2021-1074.

Issued on December 15, 2021.  Ross Landes, Deputy Director for  Regulatory
Operations, Compliance  & Airworthiness  Division, Aircraft  Certification
Service.

DATES: The FAA must  receive comments on this  proposed AD by  February 7,
2022.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


14 CFR Part 39

[Docket No. FAA-2021-1074; Project Identifier MCAI-2021-00447-R]
RIN 2120-AA64

Airworthiness Directives; Bell Textron Canada Limited Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Bell Textron Canada Limited Model 429 helicopters. This
proposed AD was prompted by reports of failed rivets between the
tailboom skin and the tail rotor (TR) gearbox support assembly. This
proposed AD would require visually inspecting the external surface of
the TR gearbox support assembly, borescope inspecting or visually
inspecting the inside of the tailboom for certain conditions, and
performing a tactile inspection. Depending on the results of the
inspections, this proposed AD would require removing certain rivets
from service or repairing gaps in accordance with FAA-approved methods.
This proposed AD would also require repeating these inspections within
certain intervals. 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 February 7, 2022.

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., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Bell
Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J
1R4, Canada; telephone 1-450-437-2862 or 1-800-363-8023; fax 1-450-433-
0272; email productsupport@bellflight.com; or at
https://www.bellflight.com/support/contact-support. 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-2021-1074; 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, the Transport Canada AD, any comments received, and
other information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Andrea Jimenez, Aerospace Engineer,
COS Program Management Section, Operational Safety Branch, Compliance &
Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY
11590; telephone (516) 228-7330; email andrea.jimenez@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-2021-1074; Project Identifier
MCAI-2021-00447-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
Andrea Jimenez, Aerospace Engineer, COS Program Management Section,
Operational Safety Branch, Compliance & Airworthiness Division, FAA,
1600 Stewart Ave., Suite 410, Westbury, NY 11590; telephone (516) 228-
7330; email andrea.jimenez@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


Transport Canada, which is the aviation authority for Canada, has
issued Canadian AD CF-2021-15, dated April 14, 2021 (Transport Canada
AD CF-2021-15), to correct an unsafe condition for Bell Textron Canada
Limited Model 429 helicopters, serial numbers (S/N) 57001 and
subsequent. Transport Canada advises of multiple in-service reports of
failed rivets at the joint between the tailboom skin and the TR gearbox
support assembly part number (P/N) 429-034-701-101 or P/N 429-035-705-
101. Transport Canada states that in-service reports also revealed a
quality escape resulted in a gapping condition between the tailboom
skin and the TR gearbox support fitting at some locations around the
joint, and that rivets of inadequate grip length have been installed at
the affected joint. This condition, if not addressed, could result in
progressive deterioration of the joint structural integrity, detachment
of the TR gearbox support assembly and loss of control of the
helicopter.

Accordingly, Transport Canada AD CF-2021-15 requires for certain
serial-numbered helicopters an initial visual inspection of the rivets
at the TR gearbox support assembly for signs of failed rivets or
inadequate grip length. Transport Canada AD CF-2021-15 also requires,
for all serial-numbered helicopters defined in the applicability,
repeating the initial visual inspection at intervals not to exceed 400
hours air time or 12 months, whichever occurs first. Transport Canada
AD CF-2021-15 also requires repair or replacement of affected parts if
discrepancies are found. Transport Canada considers its AD an interim
action and states that further AD action may follow.

FAA's Determination


These helicopters have been approved by the aviation authority of
Canada and are approved for operation in the United States. Pursuant to
the FAA's bilateral agreement with Canada, Transport Canada, its
technical representative, has notified the FAA of the unsafe condition
described in its AD. The FAA is proposing this AD after evaluating all
known relevant information and determining that the unsafe condition
described previously is likely to exist or develop on other helicopters
of these same type designs.

Related Service Information Under 1 CFR Part 51


The FAA reviewed Bell Alert Service Bulletin 429-19-47, Revision B,
dated January 27, 2021 (ASB 429-19-47). This service information
specifies procedures for an initial and repetitive general visual
inspections and detailed inspections of the affected rivets at the
joint between the tailboom skin and the TR gearbox support assembly.
This service information also specifies procedures for replacing the
affected rivets and repairing the gaps in accordance with an approved
Bell structural repair scheme.

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.

Proposed AD Requirements in This NPRM


For Model 429 helicopters with S/N 57002 through 57210 inclusive
and S/N 57212 and subsequent that, as of the effective date of this AD,
have accumulated less than 300 total hours time-in-service (TIS),
before accumulating 400 total hours TIS; or for helicopters with S/N
57002 through 57210 inclusive and S/N 57212 and subsequent that, as of
the effective date of this AD, have replaced certain part-numbered TR
gearbox support assemblies and the helicopter has accumulated less than
300 total hours TIS since the replacement of the TR gearbox support
assembly, before accumulating 400 total hours TIS since the
replacement, this proposed AD would require visually inspecting the
external surface of the TR gearbox support assembly for any rivet heads
that have separated from their tail, measuring any gaps, and before
further flight, removing affected rivets from service or repairing gaps
in accordance with FAA-approved methods.

This proposed AD would also require either borescope inspecting or
using a light source and mirror to visually inspect each rivet inside
the tailboom for missing rivet tails, rivet tails not resting against
the tailboom skin, and any rivet tails resting at the bottom of the
tailboom. Depending on the inspection results, this proposed AD would
require, before further flight, additional inspections or removing
certain parts from service. This proposed AD would require performing a
tactile inspection of certain rivets
identified in the applicable service information and depending on the
inspection results, removing rivets from service before further flight.

For Model 429 helicopters with S/N 57002 through 57210 inclusive
and S/N 57212 and subsequent that are not identified in paragraph
(g)(1) of this AD, this proposed AD would require, within 100 hours TIS
after the effective date of this AD, performing the visual inspection
of the TR gearbox support assembly, visually inspecting or borescope
inspecting each rivet inside the tailboom, performing the tactile
inspection, and accomplishing the applicable corrective actions
described previously.

For Model 429 helicopters S/N 57002 through 57210 inclusive and S/N
57212 and subsequent this proposed AD would require, within 400 hours
TIS after the initial inspections required by this proposed AD, as
applicable to your helicopter, and thereafter at intervals not to
exceed 400 hours TIS, performing the visual inspection of the TR
gearbox support assembly, visually inspecting or borescope inspecting
each rivet inside the tailboom, performing the tactile inspection, and
accomplishing the applicable corrective actions described previously.

For Model 429 helicopters S/N 57001 and 57211, this proposed AD
would require, within 400 hours TIS after the effective date of this
proposed AD and thereafter at intervals not to exceed 400 hours TIS,
performing the visual inspection of the TR gearbox support assembly,
visually inspecting or borescope inspecting each rivet inside the
tailboom, performing the tactile inspection, and accomplishing the
applicable corrective actions described previously.

Differences Between This Proposed AD and the Transport Canada AD


Transport Canada AD CF-2021-15 requires replacing any rivets, and
repairing any gaps that exceed 0.005 in (0.127 mm), in accordance with
an approved Bell structural repair scheme, and submitting certain
information to the manufacturer, whereas this proposed AD would require
removing the rivets from service and repairing the gaps using an FAA-
approved method instead. Transport Canada AD CF-2021-15 requires
replacing any rivets if any gaps are 0.005 in (0.127mm) or less,
whereas this proposed AD would require removing the rivets from
service.

Transport Canada AD CF-2021-15 also requires for certain serial-
numbered helicopters that have accumulated less than 300 hours air
time, or have replaced a certain part-numbered TR gearbox support
assembly and have accumulated less than 300 hours air time since the
replacement, within 100 hours air time or 6 months upon reaching 300
hours air time, whichever occurs first, performing the visual
inspection of the TR gearbox support assembly, visually inspecting or
borescope inspecting each rivet inside the tailboom, performing the
tactile inspection, and accomplishing the applicable corrective actions
described previously, whereas this proposed AD would require these
actions for certain helicopters before accumulating 400 total hours TIS
and for certain other helicopters, before the helicopter accumulates
400 total hours TIS since the replacement of a certain part-numbered TR
gearbox support assembly.

Additionally, Transport Canada AD CF-2021-15 requires for certain
serial-numbered helicopters that have accumulated 300 hours air time or
more, or have replaced a certain part-numbered TR gearbox support
assembly and have accumulated 300 hours air time or more since the
replacement, within 100 hours air time or 6 months, whichever occurs
first, performing the visual inspection of the TR gearbox support
assembly, visually inspecting or borescope inspecting each rivet inside
the tailboom, performing the tactile inspection, and accomplishing the
applicable corrective actions described previously, whereas this
proposed AD would require these actions within 100 hours TIS after the
effective date of this AD.

Finally, Transport Canada AD CF-2021-15 requires repeating the
visual inspection of the TR gearbox support assembly, the visual
inspection or borescope inspection of each rivet inside the tailboom,
performing the tactile inspection, and accomplishing the applicable
corrective actions described previously at intervals not to exceed 400
hours air time or 12 months, whichever occurs first, whereas this
proposed AD would require for certain serial-numbered helicopters, the
repetitive inspections to occur within 400 hours TIS after the
effective date of this AD, and thereafter at intervals not to exceed
400 hours TIS.

Interim Action


The FAA considers this proposed AD would be an interim action. Once
final action has been identified, the FAA might consider further
rulemaking.

Costs of Compliance


The FAA estimates that this AD, if adopted as proposed, would
affect 120 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 surface of the TR gearbox support assembly
would take about 0.5 work-hour for an estimated cost of $43 per
inspection and $5,160 for the U.S. fleet per inspection.

If required, replacing any affected rivets would take about 1 work-
hour and parts would cost about $110 per rivet for an estimated cost of
$195 per rivet replacement.

If required, measuring gaps would take about 0.5 work-hour for an
estimated cost of $43 per helicopter.

If required, repairing any gaps would take up to about 1 work-hour
for an estimated cost of up to $85 per repair.

Visually inspecting or borescope inspecting the inside of the
tailboom would take about 0.5 work-hour for an estimated cost of $43
per inspection and $5,160 for the U.S. fleet per inspection.

Performing a tactile inspection would take about 0.5 work-hour for
an estimated cost of $43 per inspection and $5,160 for the U.S. fleet
per inspection.

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

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
directive: