[Federal Register Volume 84, Number 151 (Tuesday, August 6, 2019)]
[Rules and Regulations]
[Pages 38115-38117]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-16729]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2018-1016; Special Conditions No. 25-753-SC]


Special Conditions: The Boeing Company Model 777-9 Airplane; 
Electronic Flight-Control System and Control-Surface-Position Awareness

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for The Boeing Company 
(Boeing) Model 777-9 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 an electronic flight-control system 
requiring control-surface-position awareness. The applicable 
airworthiness regulations do not contain adequate or

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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: Effective September 5, 2019.

FOR FURTHER INFORMATION CONTACT: Joe Jacobsen, Airplane & Flight Crew 
Interface Section, AIR-671, Transport Standards Branch, Policy and 
Innovation Division, Aircraft Certification Service, Federal Aviation 
Administration, 2200 South 216th Street, Des Moines, Washington 98198; 
telephone and fax 206-231-3158; email [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    On December 6, 2013, Boeing applied for an amendment to Type 
Certificate No. T00001SE to include the new 777-9 airplane. This 
airplane, which is a derivative of the Boeing Model 777 airplane 
currently approved under Type Certificate No. T00001SE, is a twin-
engine, transport-category airplane with seating for 495 passengers and 
a maximum takeoff weight of 775,000 pounds.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Boeing must show that the Model 777-9 airplane meets the 
applicable provisions of the regulations listed in Type Certificate No. 
T00001SE, 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 (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Boeing Model 777-9 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 type certificate for that model be amended 
later to include any other model that incorporates the same novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified 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 Boeing Model 777-9 airplane must comply with the fuel-
vent and 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 Boeing Model 777-9 airplane will incorporate the following 
novel or unusual design feature:
    An electronic flight-control system requiring control-surface-
position awareness.

Discussion

    With a response-command type of flight-control system and no direct 
coupling from the cockpit controller to control surface, such as on the 
Boeing Model 777 and 787 airplanes, the pilot is not aware of the 
actual surface-deflection position during flight maneuvers. This 
feature of this design is novel and unusual when compared to the state 
of technology envisioned in the airworthiness standards for transport-
category airplanes. These special conditions are intended to contain 
the additional safety standard.
    Some unusual flight conditions, arising from atmospheric 
conditions, or airplane or engine failures, or both, may result in full 
or nearly full control-surface deflection. Unless the flightcrew is 
made aware of excessive deflection or impending control-surface 
deflection limiting, piloted or the automated flight-control system 
control of the airplane could be inadvertently continued in a way that 
would cause loss of control, or other unsafe handling or performance 
situations.
    The special conditions require that suitable annunciation be 
provided to the flightcrew when a flight condition exists in which 
nearly full control-surface deflection occurs. Suitability of such an 
annunciation must take into account that some pilot-demanded maneuvers, 
such as a rapid roll, are necessarily associated with intended full or 
nearly full control-surface deflection. Simple alerting systems, which 
would function in both intended and unexpected control-limiting 
situations, must be properly balanced between providing needed crew 
awareness and avoiding nuisance warnings.
    The special conditions are derived initially from standardized 
requirements the Aviation Rulemaking Advisory Committee (ARAC) 
developed, a committee comprising representatives of the FAA, Europe's 
Joint Aviation Authorities (now replaced by the European Aviation 
Safety Agency), and industry representatives. In the case of some of 
these requirements, a draft notice of proposed rulemaking has been 
prepared but no final rule has been issued.
    The 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.

Discussion of Comments

    The FAA issued Notice of Proposed Special Conditions No. 25-19-06-
SC for the Boeing Model 777-9 airplane, which was published in the 
Federal Register on May 8, 2019 (84 FR 20053). No comments were 
received, and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Model 777-9 airplane. Should Boeing apply at a later date for a 
change to the type certificate to include another model incorporating 
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 one model of 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, 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 Boeing Model 777-9 airplanes.
    In addition to compliance with Sec. Sec.  25.143, 25.671, and 
25.672, the following special conditions apply.
    (1) The system design must ensure that the flightcrew is made 
suitably aware whenever the primary control means nears the limit of 
control authority. This indication should direct the pilot to take 
appropriate action to avoid the unsafe condition in

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accordance with appropriate airplane flight manual instructions. 
Depending on the application, suitable annunciations may include 
flight-deck control position, annunciator light, or surface position 
indicators. Furthermore, this requirement applies at limits of control 
authority, not necessarily at limits of any individual surface travel.
    (2) Suitability of such a display or alerting must take into 
account that some pilot-demanded maneuvers are necessarily associated 
with intended full performance, which may require full surface 
deflection. Therefore, simple alerting systems, which would function in 
both intended or unexpected control-limiting situations, must be 
properly balanced between needed flightcrew awareness and nuisance 
factors. A monitoring system, which might compare airplane motion, 
surface deflection, and pilot demand, could be useful for eliminating 
nuisance alerting.

    Issued in Des Moines, Washington, on July 31, 2019.
Victor Wicklund,
Manager, Transport Standards Branch, Policy and Innovation Division, 
Aircraft Certification Service.
[FR Doc. 2019-16729 Filed 8-5-19; 8:45 am]
 BILLING CODE 4910-13-P