DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0493; Product Identifier 2019-CE-046-AD]
RIN 2120-AA64

Airworthiness Directives; Textron Aviation, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2019-08-13 for Textron Aviation, Inc. (type certificate previously held
by Cessna Aircraft Company) Models 525, 525A, and 525B airplanes with
Tamarack active load alleviation system (ATLAS) winglets installed in
accordance with Supplemental Type Certificate (STC) SA03842NY. AD 2019-
08-13 resulted from mandatory continuing airworthiness information
(MCAI) originated by an aviation authority of another country to
identify and correct an unsafe condition on an aviation product. The
MCAI describes the unsafe condition as malfunction of the ATLAS. This
AD results from the identification of corrective actions that, if
implemented, allow operators to reactivate the ATLAS and restore
operations to normal procedures. 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 July 17,
2020.

ADDRESSES: You may send comments 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: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.

For Cranfield Aerospace Solutions Limited and Tamarack Aerospace
Group service information identified in this AD, contact Cranfield
Aerospace Solutions Ltd., Cranfield, Bedford MK43 0AL, United Kingdom;
telephone: +44 1234 754 166; FAX: +44 1234 752 375; email:
g.mitchell@cranfieldaerospace.com; internet: https://www.cranfield
aerospace.com/service/aircraft-modification-products/et.
You may review copies of the referenced service information at the FAA,
Airworthiness Products Section, Operational Safety Branch, 901 Locust,
Kansas City, Missouri 64106. For information on the availability of
this material at the FAA, call (816) 329-4148.

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-2020-0493;
or in person at Docket Operations Monday through Friday, except
Federal holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office is listed above. Comments will be available
in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Steven Dzierzynski, Avionics Engineer,
FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, New
York 11590; telephone: (516) 287-7367; fax: (516) 794-5531; email:
steven.dzierzynski@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2020-0493;
Product Identifier 2019-CE-046-AD" at the beginning of your comments.
The FAA specifically invites comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. The
FAA will consider all comments received by the closing date and may
amend this proposed AD because of those comments.

The FAA will post all comments received, without change, to https://
regulations.gov, including any personal information you provide. The
FAA will also post a report summarizing each substantive verbal contact
received about this proposed AD.

Discussion

The FAA issued AD 2019-08-13, Amendment 39-19634 (84 FR 24007; May
24, 2019) ("AD 2019-08-13") for Textron Aviation, Inc. Models 525,
525A, and 525B airplanes with Tamarack ATLAS winglets installed in
accordance with STC SA03842NY. AD 2019-08-13 prohibits all flight by
revising the operating limitations in the airplane flight manual (AFM)
and fabricating and installing a placard, until a modification has been
incorporated in accordance with an FAA-approved method. AD 2019-080-13
was based on MCAI originated by the European Aviation Safety Agency
(EASA), which is the Technical Agent for the Member States of the
European Community. EASA issued AD No. 2019-0086-E, dated April 19,
2019, to address an unsafe condition related to reports of the ATLAS
malfunctioning, which could lead to loss of control of the airplane.

Actions Since AD 2019-08-13 Was Issued

Since the FAA issued AD 2019-08-13, Cranfield Aerospace Solutions
Limited (Cranfield), the holder of STC SA03842NY, determined that
failure of the Tamarack Active Camber Surface (TACS) control units
(TCUs) was caused by a printed circuit board attachment screw coming
loose, which caused a short circuit in the TCU. EASA revised the MCAI
and issued EASA AD No. 2019-0086R1, dated August 9, 2019, to require
modifications previously developed by Cranfield to restore the safety
of the ATLAS design. Cranfield modified the TCUs with a self-locking
screw, an additional flat washer, and linear variable differential
transformer potting to prevent detachment from vibration during flight.
Cranfield also developed centering strips to modify the trailing edge
of the TACS that will return the TACS to faired when TCU power is
removed or when the TACS are "blown" out of position if ATLAS power
is removed.

Installation of the modified TCU will prevent a short circuit of
the ATLAS TCU, and installation of the centering strips to the TACS
will ensure the TACS remains in a faired position in case of
inadvertent power loss to the ATLAS.

Cranfield also revised the Tamarack maintenance manual supplement
for airplanes with the Tamarack ATLAS winglets installed to include
instructions for continued airworthiness related to the centering
strips.

Comments

The FAA gave the public the opportunity to comment on AD 2019-08-13
and received 34 comments. The majority of the commenters were operators
and maintenance personnel. The remaining commenters included Tamarack
Aerospace Group (Tamarack) and the General Aviation Manufacturers
Association (GAMA). The following presents the relevant comments
received on AD 2019-08-13 and the FAA's response to each comment.

A. Supportive Comments

Erin Saunders, Victor Ochoa, and an anonymous commenter support the
AD action.

B. Comments Regarding the FAA's Justification of an Unsafe Condition
Requests for a Thorough Investigation of the Issues

Many commenters questioned or requested clarification of the FAA's
determination that there is an unsafe condition. Seven commenters
stated the FAA should have completed a more thorough investigation and
analysis of the issues. Tamarack, Advanced Jets, LLC (Advanced Jets),
and Kenneth Adelman requested the FAA consider that the data extracted
from the incident aircraft does not agree with the pilot's description
of an aggressive roll rate. John Harris, Andrew Vann, Douglas Sayre,
and five other commenters stated that the malfunction of the European
aircraft that prompted EASA's emergency AD was caused by the failure of
the operator to comply with the manufacturer's mandatory service
bulletin. These commenters noted that there have been no failures
experienced by aircraft with winglets that have complied with the
manufacturer's mandatory service bulletin. Fourteen commenters stated
they have been operating for a considerable time with the ATLAS
winglets and have not experienced any issues. These commenters further
stated that installation of the winglets increases performance, safety,
and economy and expressed support for Tamarack as a company.

The FAA has considered the comments pertaining to the pilot's
incident report on the European airplane. At the time AD 2019-08-13 was
issued, the airplane data from the incident that prompted the EASA AD
was not available. However, the FAA analyzed the information from the
pilot's incident report and additional information received from EASA
to make the decision to issue AD 2019-08-13. Since AD 2019-08-13 was
issued, Cranfield provided data to identify the root cause of the
unsafe condition and to provide corrective action, which prompted this
superseding NPRM.

The FAA agrees with the comments regarding the operator's failure
to comply with the manufacturer's service bulletin. However, operators
are not required to comply with manufacturer service bulletins unless
mandated by the FAA or other civil aviation authority. EASA AD No.
2019-0086-E, dated April 19, 2019, which prompted AD 2019-08-13, did
not require incorporation of the service bulletins for TCU modification
and installation of the centering strips. This NPRM proposes to require
TCU modification and installation of the centering strips using
Cranfield Aerospace Solutions Limited Service Bulletin CAS/SB1480,
Issue A, dated July 2019 (Cranfield CAS/SB1480, Issue A), which
incorporates two earlier service bulletins for those actions.

The fact that commenters' personal experience with ATLAS winglets
has been positive does not negate the existence of an unsafe condition.
Despite any benefit to individual owners when the system operates
without failure, the FAA determined that an unsafe condition with the
ATLAS exists and requires corrective action.

Requests To Clarify the Hazard Caused by a Malfunction

Four commenters disputed the FAA's determination that a malfunction
of the ATLAS may reduce the pilot's ability to control the airplane.
Tamarack noted that this determination conflicts with the certification
basis and system safety analysis of the design and compliance data
during certification testing. Advanced Jets stated that the ATLAS has
been shown to be safe at speeds under 140 knots even if it
malfunctions. Kenneth Adelman stated that any reduction of pilot
control when the ATLAS malfunctions is minor and was demonstrated as
safe during the original certification of the system.

The FAA disagrees with these comments. The ATLAS complied with the
certification basis during certification testing. EASA performed the
certification flight tests, and those tests included the "worst case"
condition where the TACS were deployed in a fully asymmetric failure
position that induces the greatest roll input. EASA determined that
case to be "recoverable." However, the incident exposed a failure
mode that was not anticipated during certification, which is the basis
of this NPRM.

Requests To Clarify the FAA's Position on the Use of Speed Tape

Kenneth Adelman, Advanced Jets, and two anonymous commenters
questioned the FAA's rejection of the use speed tape to hold the
winglets flush. These commenters noted that speed tape is a product
that is widely accepted and has been used for decades.

The FAA disagrees. The statement in the AD regarding the use of
"speed tape" as a corrective action to prevent movement of the TACS
during flight is based on discussions between the FAA and EASA. Speed
tape is non-structural; therefore, it cannot be relied upon to
immobilize the TACS. The corrective action in the EASA AD required
disabling the TACS. Furthermore, any modifications mandated through AD
action become changes to the type design. As explained in AD 2019-08-
13, the speed tape did not have sufficient testing and analysis to
support the type design.

The FAA did not change this NPRM as a result of these comments.

C. Comments Regarding the NTSB Investigation

Tamarack, Advanced Jets, GAMA, and six other commenters noted that
AD 2019-08-13 contained an incorrect statement regarding the National
Transportation Safety Board (NTSB) investigation of a fatal accident
and the role the ATLAS may have played in the accident. Most of these
commenters stated that the preliminary report released by the NTSB did
not reference the ATLAS. These commenters requested the FAA correct or
remove the statement if it is not accurate.

The FAA agrees. The preamble language of AD 2019-08-13 contained a
statement pertaining to an NTSB investigation into a fatal airplane
accident. Although the airplane involved in the accident had the ATLAS
STC installed, since the NTSB has not released its factual report, that
statement should not have been in the preamble of AD 2019-08-13.

D. Comments Requesting the FAA Rescind the AD

Vincent Phillips, Stanley Jobe, and CJ Holdings requested that the
AD be rescinded and the airplanes returned to service. Two of these
commenters noted that EASA has revised its emergency AD and urged the
FAA to do the same.

The FAA partially agrees. The FAA has determined that an unsafe
condition exists on the ATLAS and that action to address the condition
is required; therefore, the FAA disagrees with rescinding the AD.
However, since AD 2019-08-13 was issued, the root cause of the failure
of the ATLAS winglets has been identified. For the reasons explained in
more detail in response to other comments, this NPRM proposes to
supersede AD 2019-08-13 to allow operation of the airplane after
modifying the ATLAS.

E. Comments Requesting Modifications to the AD

Twelve commenters noted that Cranfield's TCU upgrade and centering
strips modification eliminate the unsafe condition. These commenters
requested the FAA allow the modifications as an alternative to the
operational prohibition of AD 2019-08-13. Richard Helms and several
other commenters stated that no aircraft with these modifications have
experienced upsets. Jerome Simon requested the FAA define an
alternative method of compliance (AMOC) so the airplanes could return
to flight.

The FAA agrees. This NPRM proposes to supersede AD 2019-08-13.
Instead of the operational prohibition of AD 2019-08-13, this NPRM
proposes to require modification of the TCU and installation of the
centering strips on the TACS using Cranfield CAS/SB1480, Issue A, which
incorporates two earlier service bulletins for those actions. This NPRM
also proposes revising the Tamarack maintenance manual supplement to
add inspections for the centering strips.

F. Comments Regarding the Costs of Compliance

Several commenters requested the FAA modify the cost of compliance
to include costs associated with loss of revenue from the inability to
fly the airplanes. These commenters stated that AD 2019-08-13 is
costing operators anywhere from thousands of dollars per month to
millions of dollars in total.

The FAA disagrees. The FAA acknowledges the economic hardship for
those who depend on their airplanes for income. However, the cost
analysis in AD rulemaking actions typically includes only the actual
maintenance costs to comply with the AD and not indirect costs such as
down-time and loss of revenue.

G. Comments Requesting Clarification on Type Design Change

GAMA requested clarification on the language in AD 2019-08-13
regarding speed tape as a type design change. GAMA questioned whether a
temporary repair while waiting for a permanent design solution should
be characterized as a type design change.

The FAA agrees to provide clarification. The language in AD 2019-
08-13 is based on the FAA's Airworthiness Directives Legal
Interpretation, which explained that AD-mandated modifications to an
aircraft become part of the FAA-approved type design that must be
maintained as required by Sec. Sec. 39.7 and 39.9 (81 FR 24695, April
27, 2016). Regardless of whether a repair mandated by an AD is intended
to be permanent or temporary, the repair becomes a required change to
the type design unless and until the AD is superseded or rescinded or
the operator obtains an approved AMOC.

H. Comment Requesting Pilot Training

Three commenters requested or suggested the FAA require pilot
training and familiarity with emergency procedures in the event of an
uncommanded deflection of the ATLAS in flight.

The FAA acknowledges the commenters' request for pilot training
related to the uncommanded deflection of the ATLAS in flight. Since AD
2019-08-13 was issued, the root cause of the
failure of the ATLAS winglets has been identified. This NPRM proposes
to supersede AD 2019-08-13 to allow operation of the airplane after
modifying the ATLAS. The ATLAS modification and associated manual
revisions proposed in this NPRM are expected to mitigate the unsafe
condition without the need for additional pilot training.

I. Comment Requesting Procedure To Pull ATLAS Circuit Breaker

Kenneth Adelman requested the FAA require adding a line item to the
abnormal/emergency section in the Tamarack Winglet AFM Supplement to
indicate that, in the event of a TCAS runaway, the circuit breaker
should be pulled.

The FAA acknowledges the commenter's request to revise the Tamarack
Winglet AFM Supplement. As stated earlier, since AD 2019-08-13 was
issued, the root cause of the failure of the ATLAS winglets has been
identified. This NPRM proposes to supersede AD 2019-08-13 to allow
operation of the airplane after modifying the ATLAS. The ATLAS
modification and associated manual revisions proposed in this NPRM are
expected to mitigate the unsafe condition, precluding the need for the
requested AFM revision.

J. Comments Regarding the FAA's Rulemaking Process

Two commenters questioned the FAA's decision to issue AD 2019-08-13
as an immediately effective rule without prior notice and comment.
Richard Helms stated that this decision was neither justified nor
reasonable. Advanced Jets noted that the FAA's action is not an
emergency because of the amount of time (35 days) between issuance of
EASA's emergency AD and the FAA's issuance of AD 2019-08-13.

The FAA acknowledges the commenters' concerns that it took 35 days
to issue AD 2019-08-13 without notice and comment. The FAA worked
through the unique difficulties associated with this unsafe condition
and considered all options. The FAA coordinated with EASA and the
design approval holder before determining the best course of action to
mitigate the unsafe condition. The risk to the flying public associated
with this unsafe condition required immediate action. Allowing notice
and comment would have delayed mitigating the unsafe condition
significantly longer than 35 days. The FAA also notes that it is
proposing to supersede AD 2019-08-13 based on comments received.

Related Service Information Under 1 CFR Part 51

The FAA reviewed the following service documents proposed for
compliance with this NPRM:

Cranfield Aerospace Solutions Limited Service Bulletin
CAS/SB1480, Issue A, dated July 2019, which contains instructions to
ensure installation of a modified TCU and the TACS centering strips;

Cranfield Aerospace Solutions Limited Service Bulletin
CAS/SB1475, Issue A, dated February 2019, which contains the
instructions for installing the centering strips to the TACS; and

Tamarack Aerospace Group Cessna 525, 525A, & 525B ATLAS
Winglet Maintenance Manual Supplement, Report Number: TAG-1100-0101,
Issue G, dated September 3, 2019, which adds instructions to inspect
the centering strips and adds repetitive inspection intervals to the
Airworthiness Limitations section of the supplement for the centering
strips.

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 of this
NPRM.

Other Related Service Information

The FAA also reviewed the following documents related to this NPRM:

Tamarack Aerospace Group ATLAS Service Bulletin SBATLAS-
57-03, dated July 27, 2018, which contains instructions to remove the
ATLAS TCU and return it to the ATLAS repair facility for modification;

Tamarack Aerospace Group ATLAS Service Bulletin SBATLAS-
57-05, dated February 20, 2019, which contains instructions to install
centering strips on the TACS; and

Cranfield Aerospace Solutions Limited Service Bulletin
CAS/SB1467, Issue B, dated July 2018, which contains instructions to
remove the ATLAS TCU assembly and modify it as specified in CAS/SB1480,
Issue A.

FAA's Determination and Requirements of the Proposed AD

This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to our bilateral agreement with this State of Design Authority, it has
notified the FAA of the unsafe condition described in the MCAI and
service information referenced above. The FAA is proposing this AD
because it evaluated all information and determined the unsafe
condition exists and is likely to exist or develop on other products of
the same type design.

Costs of Compliance

The FAA estimates that this proposed AD will affect 76 products of
U.S. registry. The FAA also estimates that it would take 16 work-hours
with a parts cost of $4,314 per product to modify the TCU, 24 work-
hours with a parts cost of $199 per product to install the centering
strips, and 1 work-hour per product to revise the limitations section
as proposed by this AD. The average labor rate is $85 per work-hour.

Based on these figures, the FAA estimates the cost of the proposed
AD on U.S. operators to be $607,848, or $7,998 per product.

According to the manufacturer, 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 for
affected individuals. As a result, the FAA has included all costs in
our 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 above, I certify 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.

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)
2019-08-13, Amendment 39-19634 (84 FR 24007, May 24, 2019) and adding
the following new AD: