

[Federal Register: January 2, 2008 (Volume 73, Number 1)]
[Rules and Regulations]               
[Page 27-29]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02ja08-5]                         


[[Page 27]]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM364 Special Conditions No. 25-356-SC]

 
Special Conditions: Boeing Model 787-8 Airplane; Systems and Data 
Networks Security--Isolation or Protection From Unauthorized Passenger 
Domain Systems Access

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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

SUMMARY: These special conditions are issued for the Boeing Model 787-8 
airplane. This airplane will have novel or unusual design features when 
compared to the state of technology envisioned in the airworthiness 
standards for transport category airplanes. These novel or unusual 
design features are associated with connectivity of the passenger 
domain computer systems to the airplane critical systems and data 
networks. For these design features, the applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
protection and security of airplane systems and data networks against 
unauthorized access. 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 standards. Additional special conditions will be issued for 
other novel or unusual design features of the Boeing Model 787-8 
airplanes.

DATES: Effective Date: February 1, 2008.

FOR FURTHER INFORMATION CONTACT: Will Struck, FAA, Airplane and Flight 
Crew Interface, ANM-111, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057-
3356; telephone (425) 227-2764; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Background

    On March 28, 2003, Boeing applied for an FAA type certificate for 
its new Boeing Model 787-8 passenger airplane. The Boeing Model 787-8 
airplane will be an all-new, two-engine jet transport airplane with a 
two-aisle cabin. The maximum takeoff weight will be 476,000 pounds, 
with a maximum passenger count of 381 passengers.

Type Certification Basis

    Under provisions of 14 Code of Federal Regulations (CFR) 21.17, 
Boeing must show that Boeing Model 787-8 airplanes (hereafter referred 
to as ``the 787'') meet the applicable provisions of 14 CFR part 25, as 
amended by Amendments 25-1 through 25-117, except Sec. Sec.  25.809(a) 
and 25.812, which will remain at Amendment 25-115. If the Administrator 
finds that the applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for the 787 because of a novel 
or unusual design feature, special conditions are prescribed under 
provisions of 14 CFR 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the 787 must comply with the fuel vent and exhaust emission 
requirements of 14 CFR part 34 and the noise certification requirements 
of part 36. The FAA must also issue a finding of regulatory adequacy 
pursuant to section 611 of Public Law 92-574, the ``Noise Control Act 
of 1972.''
    The FAA issues special conditions, as defined in Sec.  11.19, under 
Sec.  11.38, and they become part of the type certification basis under 
Sec.  21.17(a)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same or similar 
novel or unusual design feature, the special conditions would also 
apply to the other model under Sec.  21.101.

Novel or Unusual Design Features

    The digital systems architecture for the 787 consists of several 
networks connected by electronics and embedded software. This proposed 
network architecture is used for a diverse set of functions, including 
the following:
    1. Flight-safety-related control and navigation and required 
systems (Aircraft Control Domain).
    2. Airline business and administrative support (Airline Information 
Domain).
    3. Passenger entertainment, information, and Internet services 
(Passenger Information and Entertainment Domain).
    The proposed architecture of the 787 is different from that of 
existing production (and retrofitted) airplanes. It allows new kinds of 
passenger connectivity to previously isolated data networks connected 
to systems that perform functions required for the safe operation of 
the airplane. Because of this new passenger connectivity, the proposed 
data network design and integration may result in security 
vulnerabilities from intentional or unintentional corruption of data 
and systems critical to the safety and maintenance of the airplane. The 
existing regulations and guidance material did not anticipate this type 
of system architecture or electronic access to aircraft systems that 
provide flight critical functions. Furthermore, 14 CFR regulations and 
current system safety assessment policy and techniques do not address 
potential security vulnerabilities that could be caused by unauthorized 
access to aircraft data buses and servers. Therefore, special 
conditions are imposed to ensure that security, integrity, and 
availability of the aircraft systems and data networks are not 
compromised by certain wired or wireless electronic connections between 
airplane data buses and networks.

Discussion of Comments

    Notice of Proposed Special Conditions No. 25-07-01-SC for the 787 
was published in the Federal Register on April 13, 2007 (72 FR 18597). 
One comment was received from the Air Line Pilots Association, 
International (ALPA) and several from Airbus.
     ALPA Comment: ALPA strongly recommended that a backup 
means must also be provided for the flightcrew to disable passengers' 
ability to connect to these specific systems.
    FAA Response: These special conditions apply to the design of 
airplane systems and networks, and would not preclude a security 
mitigation strategy that provides a means for the flightcrew to disable 
passenger connectivity to the networks or to disable access to specific 
systems connected to the airplane networks. However, the FAA would 
prefer not to dictate specific design features to the applicant but 
rather to allow applicants the flexibility to determine the appropriate 
security protections and means to address all potential vulnerabilities 
and risks posed by allowing this access. For example, the security 
protection response to a suspected network security violation could 
result in--
     The system automatically disabling passenger access to the 
network or certain functions,
     Flight deck annunciation and flightcrew disabling of 
passenger access to certain systems or capabilities, or
     Various combinations of the above.
     AIRBUS General Comment 1: In Airbus's opinion these 
special conditions leave too much room for interpretation, and related 
guidance and acceptable means of compliance should be developed in an 
advisory circular for use by future applicants.
    FAA Response: We agree that guidance is necessary and specific, 
detailed compliance guidelines and

[[Page 28]]

criteria have been developed for this aircraft certification program, 
specific to this airplane's network architecture and design, providing 
initial guidance on an acceptable means of compliance for the 787. 
Additionally, the FAA intends to participate in an industry committee 
chartered with developing acceptable means of compliance to address 
aircraft network security issues, and hopes to endorse the results of 
the work of that committee by issuing an advisory circular (AC). Until 
such time as guidance is developed for a general means of compliance 
for network security protection, these special conditions and the 
agreed-to guidance are imposed on this specific network architecture 
and design.
     AIRBUS Comment (a): Airbus stated that the requirement in 
the proposed special conditions is not ``high level'' enough because it 
considers a solution or an architecture. Airbus believes that criteria 
or assumptions for defining the domains are missing (for example, 
systems criticality, interfaces, rationale for the need to protect one 
domain from another one, trust levels * * *). The commenter maintained 
that the Aircraft Control Domain (ACD), Airline Information Domain 
(AID) and Passenger Information and Entertainment Domain (PIED) need to 
be precisely defined.
    FAA Response: We do not agree that the requirement in the proposed 
special conditions prescribes a solution or an architecture. These 
special conditions and the acceptable means of compliance were 
developed based on the Boeing-proposed 787 network architecture and 
connectivity between the Passenger Information and Entertainment Domain 
and the Aircraft Control Domain and Airline Information Domain. The 
applicant is responsible for the design of the airplane network and 
systems architecture and for ensuring that potential security 
vulnerabilities of providing passenger access to airplane networks and 
systems are mitigated to an appropriate level of assurance, depending 
on the potential risk to the airplane and occupant safety. This 
responsibility is similar to that entailed in the current system safety 
assessment process of 14 CFR 25.1309. (See also AC 25.1309-1A and the 
ARAC-recommended Arsenal version of this AC, which can be found at 
http://www.faa.gov/regulations_policies/rulemaking/committees/arac/media/tae/TAE_SDA_T2.pdf
, and SAE (Society of Automotive Engineers) 

ARP (Aerospace Recommended Practice) 4754). We believe the general 
definitions for the airplane network ``domains'' are sufficient for 
these special conditions.
     AIRBUS Comment (b): Airbus stated that in the sentence 
``The design shall prevent all inadvertent or malicious changes to, and 
all adverse impacts * * *'', the wording ``shall prevent ALL'' can be 
interpreted as a zero allowance. According to the commenter, 
demonstration of compliance with such a requirement during the entire 
life cycle of the aircraft is quite impossible because security threats 
evolve very rapidly. The only possible solution to such a requirement 
would be to physically segregate the Passenger Information and 
Entertainment Domain from the other domains. This would mean, for 
example, no shared resources like SATCOM (satellite communications), 
and no network connections. Airbus maintained that such a solution is 
not technically and operationally viable, saying that a minimum of 
communications is always necessary. Airbus preferred a less categorical 
requirement which allows more flexibility and does not prevent possible 
residual vulnerabilities if they are assessed as acceptable from a 
safety point of view. Airbus said this security assessment could be 
based on a security risk analysis process during the design, 
validation, and verification of the systems architecture that assesses 
risks as either acceptable or requiring mitigations even through 
operational procedures if necessary. Airbus noted that this process, 
based on similarities with the SAE ARP 4754 safety process, is already 
proposed by the European Organization for Civil Aviation Equipment 
(EUROCAE) Working Group 72 for consideration of safety risks posed by 
security threats or by the FAA through the document ``National Airspace 
System Communication System Safety Hazard Analysis and Security Threat 
Analysis,'' version v1.0, dated Feb. 21, 2006. Airbus said such a 
security risk analysis process could be used as an acceptable means of 
compliance addressed by an advisory circular.
    FAA Response: We agree that Airbus's interpretation of zero 
allowance for any ``inadvertent or malicious changes to, and all 
adverse impacts'' to airplane systems, networks, hardware, software, 
and data is correct. However, this does not prevent allowing 
appropriate access if the design incorporates robust security 
protection means and procedures to prevent inadvertent and intentional 
actions that could adversely impact airplane systems, functionality, 
and airworthiness. Airbus commented that ``a minimum of communications 
is always necessary.'' Unauthorized users, however, must not be allowed 
communication access to aircraft systems and equipment in such a way 
that inadvertent or intentional actions can have any adverse impact on 
the aircraft systems, equipment, and data. Technology exists which 
allows sharing of resources without allowing unauthorized access and 
inappropriate actions to systems and data. As previously mentioned, 
detailed compliance guidelines and criteria, specific to the 787 
network architecture, have been developed into an acceptable means of 
compliance for this airplane certification program. In addition, we 
intend to participate in future related industry committees (such as 
SAE S-18, which is currently revising ARP 4754, EUROCAE Working Group 
72, and RTCA (RTCA, Incorporated; formerly Radio Technical Commission 
for Aeronautics) Special Committee 216). These groups will be 
developing additional aircraft network security guidance, and we hope 
to be able to endorse the results of their efforts as an acceptable 
means of compliance for network security issues on future aircraft 
certification programs.
     AIRBUS Comment (c): Airbus said that this requirement is 
limited to the design (``The design shall prevent all inadvertent or 
malicious changes * * * ''), but security solutions are always 
dependent on organizational procedures. Airbus said that because the 
efficiency of a security solution relies on the weakest link in the 
overall chain (design, operations, organizations, processes, * * *), 
the robustness of the design may be impaired (by, for instance, cabin 
crew interfaces being used by unauthorized passengers) if equivalent 
security requirements are not mandated for other involved parties, as, 
for example, through an operational or maintenance approval.
    FAA Response: The applicant is responsible for developing a design 
compliant with these special conditions and other applicable 
regulations. The design may include specific technology and 
architecture features, as well as operator requirements, operational 
procedures and security measures, and maintenance procedures and 
requirements, to ensure an appropriate implementation that can be 
properly used and maintained to ensure safe operations and continued 
operational safety. These special conditions do not preclude 
organizational, process, operational, monitoring, or maintenance 
procedures and requirements from being part of the design to ensure 
security protection. As with other aircraft models, the operator is 
obligated to

[[Page 29]]

operate and maintain the aircraft in conformance with regulations and 
with requirements for operation and maintenance of the product.
     AIRBUS Comment (d): Airbus noted that the special 
conditions consider only interference between the Passenger Information 
and Entertainment Domain (PIED) and the Airline Information Domain or 
Aircraft Control Domain. It notes there is no requirement for 
protecting the Aircraft Control Domain from the Airline Information 
Domain, if this one is considered less trusted than the Aircraft 
Control Domain. As an example, it said that the Airline Information 
Domain could implement portable electronic flight bags.
    FAA Response: These special conditions address only the interfaces 
between the passenger domain (PIED) and other aircraft systems and 
networks. Other interfaces and accesses are addressed by current 
regulations and policy, and by another proposed special conditions.
     AIRBUS Comment (e): Airbus said that, depending on the 
meaning of ``unauthorized external access,'' these special conditions 
may be redundant to proposed special conditions 25-07-02-SC (see 
comment ``b'' about 25-07-02-SC).
    FAA Response: These special conditions are not redundant. The 
passenger PIED and its security implementation are part of the airplane 
model and type design, and are not considered ``external'' to the 
aircraft. In reviewing the Boeing-proposed 787 network architecture and 
design during development of these special conditions, we determined 
the need for two separate special conditions. To ensure appropriate 
security protection of the aircraft and its systems, one special 
condition was needed for access from the passenger domain, and one for 
access from sources external to the airplane.
     AIRBUS proposed text revision: Airbus proposed the 
following revised wording for these special conditions.

    The applicant shall ensure that security threats from all points 
within the Passenger Information and Entertainment Domain, are 
identified and risk mitigation strategies are implemented to protect 
the Aircraft Control Domain and Airline Information Services Domain 
from adverse impacts reducing the aircraft safety.

    FAA Response: As noted previously, the purpose of these special 
conditions is to ensure security protection from all inadvertent or 
malicious changes to, and all adverse impacts to, airplane systems, 
networks, hardware, software, and data from accesses through the 
passenger domain. We do not believe the commenter's proposal is 
specific enough to achieve this purpose, and we will retain the current 
wording.

Applicability

    As discussed above, these special conditions are applicable to the 
787. Should Boeing apply at a later date for a change to the type 
certificate to include another model on the same type certificate 
incorporating the same novel or unusual design features, these special 
conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
of the 787. It is not a rule of general applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

0
The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 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 Boeing Model 787-8 airplane.

    The design shall prevent all inadvertent or malicious changes 
to, and all adverse impacts upon, all systems, networks, hardware, 
software, and data in the Aircraft Control Domain and in the Airline 
Information Domain from all points within the Passenger Information 
and Entertainment Domain.

    Issued in Renton, Washington, on December 21, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-25467 Filed 12-31-07; 8:45 am]

BILLING CODE 4910-13-P
