DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0589; Product Identifier 2017-SW-020-AD]
RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron Canada Limited
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2016-02-06 for Bell Helicopter Textron Canada Limited (Bell) Model 429
helicopters. AD 2016-02-06 requires inspecting certain tail rotor (T/R)
pitch link bearing bores for corrosion and pitting. AD 2016-02-06 also
requires a repetitive inspection of the sealant and
repeating the inspections for corrosion and pitting if any sealant is
missing. Since the FAA issued AD 2016-02-06, the FAA determined
additional part-numbered T/R pitch link assemblies (links) are affected
by the same unsafe condition and an additional repetitive inspection is
necessary to address the unsafe condition. This proposed AD would
retain the requirements of AD 2016-02-06, expand the applicability, and
add a repetitive inspection. The actions of this proposed AD are
intended to address an unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by October 21,
2019.

ADDRESSES: You may send comments by any of the following methods:

Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the
online instructions for sending your comments electronically.

Fax: 202-493-2251.

Mail: Send comments to the U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590-0001.

Hand Delivery: Deliver to the "Mail" address between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2019-0589;
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, the Transport Canada AD, the economic evaluation, any comments
received, and other information. The street address for Docket
Operations is in the ADDRESSES section. Comments will be available in
the AD docket shortly after receipt.

For service information identified in this NPRM, contact Bell
Helicopter Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel,
Quebec J7J1R4; telephone (450) 437-2862 or (800) 363-8023; fax (450)
433-0272; or at http://www.bellcustomer.com/files/. You may review the
referenced service information at the FAA, Office of the Regional
Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort
Worth, TX 76177.

FOR FURTHER INFORMATION CONTACT: Scott Franke, Aviation Safety
Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA,
10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110;
email scott.franke@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to participate in this rulemaking by submitting
written comments, data, or views. The FAA also invites comments
relating to the economic, environmental, energy, or federalism impacts
that might result from adopting the proposals in this document. The
most helpful comments reference a specific portion of the proposal,
explain the reason for any recommended change, and include supporting
data. To ensure the docket does not contain duplicate comments,
commenters should send only one copy of written comments, or if
comments are filed electronically, commenters should submit them only
one time.

The FAA will file in the docket all comments that the FAA receives,
as well as a report summarizing each substantive public contact with
FAA personnel concerning this proposed rulemaking. Before acting on
this proposal, the FAA will consider all comments received on or before
the closing date for comments. The FAA will consider comments filed
after the comment period has closed if it is possible to do so without
incurring expense or delay. The FAA may change this proposal in light
of the comments received.

Discussion

The FAA issued Emergency AD 2016-02-06 which was published in the
Federal Register as a Final rule; request for comments on February 2,
2016, at 81 FR 5367 ("AD 2016-02-06"). AD 2016-02-06 applies to Bell
Model 429 helicopters with a T/R link part number (P/N) 429-012-112-
101, -101FM, -103, or -103FM installed. AD 2016-02-06 requires
inspecting P/N 429-012-112-101 and 429-012-112-103 T/R link bearing
bores for any aluminum oxide corrosion and then cleaning the affected
area of the T/R link and inspecting for any pitting. If there is any
corrosion or any pitting, AD 2016-02-06 requires replacing the T/R
link. If there is no corrosion or pitting, AD 2016-02-06 requires
applying corrosion preventative sealant. AD 2016-02-06 also requires,
for all applicable T/R/links, repetitively inspecting the bearing bore
for missing sealant.

AD 2016-02-06 was prompted by AD No. CF-2016-01, dated January 5,
2016, issued by Transport Canada, which is the aviation authority for
Canada, to correct an unsafe condition for Bell Model 429 helicopters.
Transport Canada advised of an incident in which a T/R link on a Model
429 helicopter failed, causing vibration and difficulty controlling the
helicopter. According to Transport Canada, the failure was caused by a
crack that had initiated at a corrosion pit between the roll staked lip
of the bearing and the beveled edge of the link. Transport Canada
stated deficiencies in the application of corrosion resistant finishes
to the link during manufacturing caused the corrosion.

Transport Canada further advised that this condition, if not
detected, could result in failure of a link and loss of control of the
helicopter. For these reasons, the Transport Canada AD required
inspection of the T/R link and replacement of any link with corrosion.
The Transport Canada AD also required application of corrosion
preventative sealant and re-identification of the T/R link.

Actions Since AD 2016-02-06 Was Issued

Since the FAA issued AD 2016-02-06, Transport Canada revised its AD
and issued AD No. CF-2016-01R1, dated February 10, 2016, and AD No. CF-
2016-01R2, dated April 12, 2017 (AD CF-2016-01R2). Both revised
Transport Canada ADs clarify the applicable P/Ns, address spare parts,
and address parts installed on-condition prior to December 7, 2015. AD
CF-2016-01R2 includes a terminating action for the repetitive
inspections.

Since the FAA issued AD 2016-02-06, improved T/R link P/N 429-012-
112-111 and -113 have been developed that include the corrosion
preventative sealant installed; however, recurring inspections of the
sealant of these T/R links are still necessary since they are subject
to the same unsafe condition due to design similarity. Some T/R links
P/N 429-012-112-101 and -103 have also been field modified and re-
identified as T/R links P/N 429-012-112-111FM and -113FM, and continue
to need recurring inspections of the sealant as they are also subject
to the same unsafe condition due to design similarity. Accordingly, the
FAA proposes adding T/R link P/Ns 429-012-112-111, -111FM, -113, and -
113FM to the applicability.

Additionally, because the corrosion preventative sealant could
become damaged, not maintain seal, or wear away with use of the
helicopter, this proposed AD includes a repetitive 12-month inspection
with the corrosion preventative sealant removed. This proposed
requirement is a more in-depth inspection for corrosion and pitting,
due to any potential loss of the seal and build up of corrosion underneath
the sealant over time.

This proposed AD would also change the visual inspection of each
cleaned T/R link for pitting by requiring use of 10X or higher power
magnification as specified in Bell Helicopter's related service
information.

Comments on AD 2016-02-06

After our Final rule; request for comments was published, the FAA
received comments from one commenter.

Request

Bell requested the FAA clarify its statement in the preamble of AD
2016-02-06 explaining that AD 2016-02-06 requires inspecting each T/R
link bearing bore for pitting after cleaning while the Transport Canada
AD requires inspecting for corrosion after cleaning. The FAA determined
that an inspection for pitting instead of corrosion after cleaning was
a more effective method of detecting the unsafe condition. While the
cleaning process may remove corrosion, it will not remove pitting in
the metal.

Bell also disagreed that a 10X or higher magnification is necessary
for the inspection and stated that a visual inspection of the sealant
is sufficient. The FAA disagrees. Corrosion can start in any small
opening of the sealant and may be undetectable without magnification.

Lastly, Bell disagreed with AD 2016-02-06 not requiring re-
identification of the link P/N. Bell stated that a modified part
requires a distinct identification and that not mandating the re-
identification could cause confusion among operators. The FAA disagrees
that re-identification of the link P/N is necessary to correct the
unsafe condition. If an owner or operator would like to add "FM" to
the P/N to indicate that corrosive preventative sealant has been
applied, then they may. However, the AD requires repetitive inspections
for all applicable parts, including those with "FM" in the P/N.
Accordingly, re-identification is not necessary and does not affect
compliance with the AD.

FAA's Determination

This helicopter has been approved by the aviation authority of
Canada and is approved for operation in the United States. Pursuant to
our bilateral agreement with Canada, Transport Canada, its technical
representative, has notified us of the unsafe condition described in
the Canadian AD. The FAA is proposing this AD because the FAA evaluated
all the relevant information and determined the unsafe condition
described previously is likely to exist or develop in other products of
the same type design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Bell Helicopter Alert Service Bulletin 429-15-26,
dated December 7, 2015 (ASB 429-15-26), which advises of reports of
corrosion on T/R links between the roll staked lip of bearing P/N 429-
312-107-103 and the beveled edge of T/R link P/Ns 429-012-112-101/-103.
ASB 429-15-26 specifies inspecting each T/R link bearing bore between
the roll staked lip of the bearing outer race and the link bearing bore
with 10X magnification for corrosion and if there is corrosion,
replacing the link. If there is no corrosion, ASB 429-15-26 specifies
cleaning the area and performing a second inspection with 10X
magnification for corrosion. If there is corrosion, ASB 429-15-26
specifies replacing the link. If there is no corrosion, ASB 429-15-26
specifies removing the torque stripe, cleaning the area, and applying
corrosion preventative sealant. ASB 429-15-26 also specifies re-
identifying the P/Ns as 429-012-112-101FM/-103FM. Further, ASB 429-15-
26 specifies a repetitive inspection of the sealant and reapplication
if the sealant is damaged.

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

This proposed AD would retain the requirements of AD 2016-02-06 and
would add P/Ns 429-012-112-111, -111FM, -113, and -113FM to the
applicability. This proposed AD would also add use of 10X or higher
power magnification to the visual inspection of each cleaned T/R link
for pitting and a repetitive 12-month inspection with the corrosion
preventative sealant removed.

Differences Between This Proposed AD and the Transport Canada AD

This proposed AD applies to helicopters with certain link P/Ns
installed, whereas the Transport Canada AD applies to helicopters with
certain serial numbers instead. This proposed AD requires inspecting
the bearing bores for any pitting after cleaning the T/R link, while
the Transport Canada AD requires inspecting for corrosion after
cleaning the T/R link. This proposed AD requires performing the
inspections with 10X or higher magnification, while the Transport
Canada AD does not specify any magnification. This proposed AD does not
require re-identifying the P/N of the link, whereas the Transport
Canada AD does. The Transport Canada AD also provides a terminating
action to the repetitive sealant inspection, while this proposed AD
does not. This proposed AD also requires a repetitive inspection with
the corrosion preventative sealant removed and reapplied, whereas the
Transport Canada AD does not.

Interim Action

The FAA considers this proposed AD to be an interim action. The
design approval holder is currently developing a modification that will
address the unsafe condition identified in this proposed AD. Once this
modification is developed, approved, and available, the FAA might
consider additional rulemaking.

Costs of Compliance

The FAA estimates that this proposed AD would affect 93 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.

Inspecting the set of T/R links (eight bearings) for corrosion
would take about one work-hour for an estimated cost of $85 per
helicopter and $7,905 for the U.S. fleet per inspection cycle. Cleaning
and inspecting the set of T/R links for pitting would take about one
work-hour for an estimated cost of $85 per helicopter. Replacing a T/R
link would require no additional work-hours after inspection and
required parts cost $2,739 for an estimated replacement cost of $2,739
per T/R link. Removing the torque stripe, cleaning, and applying
sealant to the set of T/R links would take about one work-hour with a
negligible parts cost for an estimated cost of $85 per helicopter.
Inspecting the sealant on a set of T/R links would take about one work-
hour for an estimated cost of $85 per helicopter and $7,905 for the
U.S. fleet per inspection cycle.

According to Bell Helicopter's service information some of the
costs of this proposed AD may be covered under warranty, thereby
reducing the cost impact on affected individuals. The FAA does not
control warranty coverage by Bell Helicopter. Accordingly, the FAA has
included all costs in its cost estimate.

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 that this proposed regulation:

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.

The FAA prepared an economic evaluation of the estimated costs to
comply with this proposed AD and placed it in the AD docket.

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 removing Airworthiness Directive (AD)
2016-02-06, Amendment 39-18387 (81 FR 5367, February 2, 2016), and
adding the following new airworthiness directive (AD):