[Federal Register Volume 88, Number 139 (Friday, July 21, 2023)]
[Rules and Regulations]
[Pages 46955-46956]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-15468]



[[Page 46955]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2023-1242; Special Conditions No. 25-839-SC]


Special Conditions: Textron Aviation, Inc. Model 560XL(XLS+) 
Airplane; Electronic System Security Protection From Unauthorized 
Internal Access

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Textron Aviation, 
Inc. (Textron) Model 560XL(XLS+) airplane. This airplane will have a 
novel or unusual design feature when compared to the state of 
technology envisioned in the airworthiness standards for transport-
category airplanes. This design feature is associated with the 
installation of a digital system that contains a wireless and hardwired 
network with hosted application functionality that allows access, from 
a source internal to the airplane, to the airplane's internal 
electronic component. The applicable airworthiness regulations do not 
contain adequate or appropriate safety standards for this design 
feature. These special conditions contain the additional safety 
standards that the Administrator considers necessary to establish a 
level of safety equivalent to that established by the existing 
airworthiness standards.

DATES: This action is effective on Textron Aviation, Inc. on July 21, 
2023. Send comments on or before September 5, 2023.

ADDRESSES: Send comments identified by Docket No. FAA-2023-1242 using 
any of the following methods:
     Federal eRegulations Portal: Go to https://www.regulations.gov/ and follow the online instructions for sending 
your comments electronically.
     Mail: Send comments to Docket Operations, M-30, U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
     Docket: Background documents or comments received may be 
read at https://www.regulations.gov/ at any time. Follow the online 
instructions for accessing the docket or go to Docket Operations in 
Room W12-140 of the West Building Ground Floor at 1200 New Jersey 
Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday through 
Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Thuan T. Nguyen, Avionics Software & 
Components Unit, AIR-626D, Technical Innovation Policy Branch, Policy 
and Innovation Division, Aircraft Certification Service, Federal 
Aviation Administration, 2200 South 216th Street, Des Moines, 
Washington 98198; telephone and fax 206-231-3365; email 
[email protected].

SUPPLEMENTARY INFORMATION: The substance of these special conditions 
has been published in the Federal Register for public comment in 
several prior instances with no substantive comments received. 
Therefore, the FAA finds, pursuant to 14 CFR 11.38(b), that new 
comments are unlikely, and notice and comment prior to this publication 
are unnecessary.

Privacy

    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in title 
14, Code of Federal Regulations (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 FAA will also post 
a report summarizing each substantive verbal contact received about 
these special conditions.

Confidential Business Information

    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 
these special conditions contain commercial or financial information 
that is customarily treated as private, that you actually treat as 
private, and that is relevant or responsive to these special 
conditions, 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 the indicated comments will not be 
placed in the public docket of these special conditions. Send 
submissions containing CBI to Thuan T. Nguyen, Avionics Software & 
Components Unit, AIR-626D, Technical Innovation Policy Branch, Policy 
and Innovation Division, Aircraft Certification Service, Federal 
Aviation Administration, 2200 South 216th Street, Des Moines, 
Washington 98198; telephone and fax 206-231-3365; email 
[email protected]. Comments the FAA receives, which are not 
specifically designated as CBI, will be placed in the public docket for 
these special conditions.

Comments Invited

    The FAA invites interested people to take part in this rulemaking 
by sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data.
    The FAA will consider all comments received by the closing date for 
comments, and will consider comments filed late if it is possible to do 
so without incurring delay. The FAA may change these special conditions 
based on the comments received.

Background

    On June 30, 2021, Textron Aviation, Inc. applied for an amended 
type certificate (ATC) for the installation of a digital system that 
contains a wireless and hardwired network with hosted application 
functionality that allows access, from sources internal to the 
airplane, to the airplane's internal electronic components. The Textron 
Model 560XL(XLS+) airplane, which is a derivative of the Model 560XL 
currently approved under Type Certificate No. A22CE, is a two-engine 
transport category airplane. The maximum seating capacity is 12 
passengers and 2 crew members. The maximum takeoff weight is 20,200 to 
20,330 pounds, depending on the specific variant.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Textron must show that the Model 560XL(XLS+) airplane, as 
changed, continues to meet the applicable provisions of the regulations 
listed in Type Certificate No. A22CE or the applicable regulations in 
effect on the date of application for the change, except for earlier 
amendments as agreed upon by the FAA.
    If the Administrator finds that the applicable airworthiness 
regulations (e.g., 14 CFR part 25) do not contain adequate or 
appropriate safety standards

[[Page 46956]]

for the Textron Model 560XL(XLS+) airplane because of a novel or 
unusual design feature, special conditions are prescribed under the 
provisions of Sec.  21.16.
    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant apply for an ATC to modify any 
other model included on the same type certificate to incorporate the 
same novel or unusual design feature, these special conditions would 
also apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the Textron Model 560XL(XLS+) airplane must comply with the 
exhaust-emission requirements of 14 CFR part 34, and the noise-
certification requirements of 14 CFR part 36.
    The FAA issues special conditions, as defined in 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.101.

Novel or Unusual Design Features

    The Textron Model 560XL(XLS+) airplane will incorporate a novel or 
unusual design feature, which is the installation of a digital system 
that contains a wireless and hardwired network with hosted application 
functionality that allows access, from sources internal to the 
airplane, to the airplane's internal electronic components.

Discussion

    The Textron Model 560XL(XLS+) airplane electronic system 
architecture and network configuration change is novel or unusual for 
commercial transport airplanes because it is composed of several 
connected wireless and hardwired networks. This proposed system and 
network architecture is used for a diverse set of airplane functions, 
including:
     Flight-safety related control and navigation systems,
     Airline business and administrative support, and
     Passenger entertainment.
    The airplane's control domain and airline information services 
domain of these networks perform functions required for the safe 
operation and maintenance of the airplane. Previously, these domains 
had very limited connectivity with other network sources. This network 
architecture creates a potential for unauthorized persons to access the 
aircraft control domain from sources internal to the airplane, and 
presents security vulnerabilities related to the introduction of 
computer viruses and worms, user errors, and intentional sabotage of 
airplane electronic assets (networks, systems, and databases) critical 
to the safety and maintenance of the airplane.
    The existing FAA regulations did not anticipate these networked 
airplane-system architectures. Furthermore, these regulations and the 
current guidance material do not address potential security 
vulnerabilities, which could be exploited by unauthorized access to 
airplane networks, data buses, and servers. Therefore, these special 
conditions ensure that the security (i.e., confidentiality, integrity, 
and availability) of airplane systems will not be compromised by 
unauthorized wireless or hardwired electronic connections from within 
the airplane. These special conditions also require the applicant to 
provide appropriate instruction to the operator to maintain all 
electronic-system safeguards that have been implemented as part of the 
original network design so that this feature does not allow or 
reintroduce security threats.
    These special conditions contain the additional safety standards 
that the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.

Applicability

    As discussed above, these special conditions are applicable to the 
Textron Model 560XL(XLS+) airplane. Should Textron apply at a later 
date for an amended type certificate to modify any other model included 
on Type Certificate No. A22CE to incorporate the same novel or unusual 
design feature, these special conditions would apply to that model as 
well.

Conclusion

    This action affects only a certain novel or unusual design feature 
on Textron Model 560XL(XLS+) airplane. It is not a rule of general 
applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

Authority Citation

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, and 
44704.

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for the Textron 560XL(XLS+) airplane for 
airplane electronic-system internal access.
    1. The applicant must ensure that the design provides isolation 
from, or airplane electronic-system security protection against, access 
by unauthorized sources internal to the airplane. The design must 
prevent inadvertent and malicious changes to, and all adverse impacts 
upon, airplane equipment, systems, networks, and other assets required 
for safe flight and operations.
    2. The applicant must establish appropriate procedures to allow the 
operator to ensure that continued airworthiness of the airplane is 
maintained, including all post-type-certification modifications that 
may have an impact on the approved electronic-system security 
safeguards.

    Issued in Kansas City, Missouri, on July 17, 2023.
Patrick R. Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2023-15468 Filed 7-20-23; 8:45 am]
BILLING CODE 4910-13-P