Special Conditions: Aerospace Design & Compliance, LLC (ADC), Textron Aviation Inc. Model 550, 560, and 560XL Airplane; Electronic System Security Protection From Unauthorized Internal Access

AGENCY:

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

ACTION:

Final special conditions; request for comments.

SUMMARY:

These special conditions are issued for the Textron Aviation, Inc. (Textron) 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series airplane as modified by Aerospace Design & Compliance, LLC (ADC). These airplanes 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 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 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 ADC on May 22, 2024. Send comments on or before July 8, 2024.

ADDRESSES:

Send comments identified by Docket No. FAA-2024-0721 using any of the following methods:

• Federal eRegulations Portal: Go to 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 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 Policy Branch, Policy and Standards Division, Aircraft Certification Service, Federal Aviation Administration, 2200 South 216th Street, Des Moines, Washington 98198; telephone and fax 206-231-3365; email Thuan.T.Nguyen@faa.gov.

SUPPLEMENTARY INFORMATION:

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. The FAA may change these special conditions based on the comments received.

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 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 the individual listed in the FOR FURTHER INFORMATION CONTACT section above. Comments the FAA receives, which are not specifically designated as CBI, will be placed in the public docket for these special conditions.

Background

On September 02, 2022, ADC applied for a supplemental type certificate (STC) for the installation of an electronic networks system architecture 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 in the Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series airplane. The Textron Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series airplane, currently approved under Type Certificate No. A22CE, is a two-engine transport category airplane. The maximum seating capacity for the Model 550 (Bravo) is 11 passengers and 2 crew members. The maximum takeoff weight is 14,800 pounds. The seating capacity for the Model 560 (Ultra Encore) is 11 passengers and 2 crew members. The maximum takeoff weight is 16,630 pounds. The seating capacity for the Model 560XL (Excel) is 12 passengers and 2 crew members. The maximum takeoff weight is 20,200 pounds.

Type Certification Basis

Under the provisions of title 14, Code of Federal Regulations (14 CFR) 21.101, ADC must show that the Textron Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel), 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 for the Textron Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) airplane because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.

Special conditions are initially applicable to the model for which they are issued. Should the applicant apply for a supplemental type certificate 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 § 21.101.

In addition to the applicable airworthiness regulations and special conditions, the Textron Aviation Inc. Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) 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 § 11.38, and they become part of the type certification basis under § 21.101.

Novel or Unusual Design Features

The STC requested by ADC for the Textron Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series airplane will incorporate the following novel or unusual design feature: 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 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series airplane system architecture and network configuration change proposed by ADC is novel or unusual for transport category airplanes because it is composed of several connected wireless and hardwired networks. This 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 airplane-control domain and airline information-services 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 applicable 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 hardwired or wireless electronic connections from within the airplane. These special conditions also require the applicant to provide appropriate instructions 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 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series airplane, as proposed to be modified by ADC. Should ADC apply at a later date for a supplemental 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 of ADC's proposed STC for the Textron Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series of airplane. It is not a rule of general applicability and affects only the applicant who applied to the FAA for approval of that feature on the airplane.

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 Textron Model 550 (Bravo), 560 (Ultra Encore), and 560XL (Excel) series airplanes, as modified by ADC, for airplane electronic-system internal access:

1. The applicant must ensure that the design provides isolation from, or airplane electronic network 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, or 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 network system security safeguards.