[Federal Register Volume 83, Number 247 (Thursday, December 27, 2018)]
[Rules and Regulations]
[Pages 66607-66609]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-28116]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No.FAA-2018-0918; Notice No. 23-291-SC]


Special Conditions: Innovative Solutions & Support, Inc.; Textron 
Aviation, Inc. Model B200-Series Airplanes; Autothrust Functions

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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

SUMMARY: These special conditions are issued for Textron Aviation, Inc. 
B200-series airplanes. These airplanes as modified by Innovative 
Solutions & Support, Inc., will have a novel or unusual design feature 
associated with an autothrust system. The applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
this design feature. These special conditions contain the additional 
safety standards the Administrator considers necessary to establish a 
level of safety equivalent to that established by the existing 
airworthiness standards.

DATES: These special conditions are effective December 27, 2018.

FOR FURTHER INFORMATION CONTACT: Jeff Pretz, AIR-691, Regulations & 
Policy Section, Small Airplane Standards Branch, Policy & Innovation 
Division, Aircraft Certification Service, Federal Aviation 
Administration, 901 Locust; Kansas City, Missouri 64106; telephone 
(816) 329-3239; facsimile (816) 329-4090; email [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    On December 14, 2017, Innovative Solutions & Support, Inc. 
(Innovative Solutions), applied for a supplemental type certificate for 
installation of an autothrust system (ATS)--also known as an 
autothrottle system--in Textron Aviation, Inc., (Textron) B200-series 
airplanes. The B200-series airplanes are powered by two Pratt & Whitney 
PT6A turbo-propeller engines--depending on airplane model--that can 
carry thirteen passengers, including two flightcrew members. These 
airplanes have a service ceiling up to 35,000-feet and a maximum 
takeoff weight of up to 12,500 pounds in the normal category. These 
airplanes are approved for single-pilot operation.
    The installation of an ATS in Textron B200-series airplanes is 
intended to reduce pilot workload. The ATS is useable in all phases of 
flight except below decision height on approach. The system includes 
torque control and airspeed modes along with monitors to prevent the 
system from exceeding critical engine or airspeed limits. Throttle 
movement is provided by a stepper motor acting through a linear 
actuator, which acts as a link between the stepper motor and throttle. 
The liner actuator can be overridden by pilot movement of the throttle 
and automatically disengages upon disagreement in the expected throttle 
position versus its actual position.
    Section 23.1329, amendment 23-49, only contained requirements for 
automatic pilot systems that act on the airplane flight controls. 
Autothrust systems are automatic systems that act on the thrust 
controls. These systems provide enhanced automation and safety, but may 
also introduce pilot confusion, countering the safety benefit. 
Transport Airplane regulation 14 CFR 25.1329, amendment 25-119, 
addresses these concerns. Therefore, these special conditions are based 
on Sec.  25.1329 and provide additional requirements to standardize the 
pilot interface and system behavior and enhance pilot awareness of 
system active and armed modes.

Type Certification Basis

    Under the provisions of Sec.  21.101, Innovative Solutions must 
show that B200-series airplanes, as changed, continue to meet the 
applicable provisions of the regulations incorporated by reference in 
Type Certificate (TC) No. A24CE \2\ or the applicable regulations in 
effect on the date of application for the change. The regulations 
incorporated by reference in the type certificate are commonly referred 
to as the ``original type certification basis.'' The regulations 
incorporated by reference in TC No. A24CE are as follows: 14 CFR part 
23, amendments 23-1 through 23-9, plus various later part 23 
amendments--depending on the model and serial number of the airplane--
as noted on Type Certification Data Sheet A24CE.
---------------------------------------------------------------------------

    \2\ See http://rgl.faa.gov/.
---------------------------------------------------------------------------

    If the Administrator finds the applicable airworthiness regulations 
(i.e., 14 CFR part 23) do not contain adequate or appropriate safety 
standards for B200-series airplanes 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(s) for 
which they are issued. Should the applicant apply for a supplemental 
type certificate to modify any other model included on

[[Page 66608]]

the same type certificate to incorporate the same or similar novel or 
unusual design feature, the FAA would apply these special conditions to 
the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, B200-series airplanes 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

    Textron B200-series airplanes will incorporate the following novel 
or unusual design features:
    Autothrust system, which provides commands to two linear actuators, 
one attached to each throttle lever, that automatically control thrust 
on each engine. The autothrust system can be operated in either Torque 
Control Mode or Airspeed Mode.

Discussion

    The part 23 airworthiness regulations in the type certification 
basis do not contain appropriate safety standards for an ATS 
installation; hence, the need for special conditions. However, part 25 
regulations contain appropriate airworthiness standards; therefore, 
these special conditions are derived from Sec.  25.1329, amendment 25-
119. Sections 23.143, amendment 23-50, and 23.1309, amendment 23-62, 
would be used instead of the corresponding part 25 regulations 
referenced in Sec.  25.1329.

Discussion of Comments

    Notice of proposed special conditions No. 23-18-03-SC for Textron 
B200-series airplanes was published in the Federal Register on October 
26, 2018.\3\ We received comments from two commenters.
---------------------------------------------------------------------------

    \3\ See 83 FR 54057.
---------------------------------------------------------------------------

    An individual commenter requested that we clarify the wording of or 
include definitions for ``normal,'' rare-normal,'' and ``non-normal'' 
conditions to establish a clear intent relating to the probability of 
significant transients instead of using 14 CFR part 25 language. In 
support of this request, the commenter stated that because the special 
conditions do not define ``normal,'' ``rare-normal,'' and ``non-
normal'' conditions in reference to allowable transients, this results 
in an undefined probability of ``non-fatal injuries'' as contained in 
the significant transient definition in paragraph 1(l)(2) of the 
proposed special condition.
    We agree and clarify the terms ``normal,'' ``rare-normal,'' and 
``non-normal'' in these special conditions. These terms are defined in 
Advisory Circular 25.1329-1C, ``Approval of Flight Guidance Systems.'' 
Retaining common terms and definitions--when possible--across product 
lines for standardization are beneficial to all stakeholders. We have 
added footnotes to the terms in the special conditions language to 
identify where the definitions may be found.
    Another individual commenter supports these special conditions. 
However, the commenter requests specific information about the safety 
hazards.
    Additional information about safety hazards and the considerations 
that should be made when conducting a safety assessment may also be 
found in Advisory Circular 25.1329-1C. We did not make any changes to 
the proposed special conditions based on this comment.
    Except for the change previously discussed, these special 
conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to 
Textron B200-series airplanes. Should Innovative Solutions apply at a 
later date for a supplemental type certificate to modify any other 
model included on TC No. A24CE to incorporate the same novel or unusual 
design feature, the FAA would apply these special conditions to that 
model as well.
    Under standard practice, the effective date of final special 
conditions would be 30 days after the date of publication in the 
Federal Register; however, as the supplemental type certification date 
for the Textron Aviation B200 series airplanes is imminent, pursuant to 
5 U.S.C. 553(d) the FAA finds that good cause exists to make these 
special conditions effective upon issuance.

Conclusion

    This action affects only certain novel or unusual design features 
on one model series of airplanes. It is not a rule of general 
applicability and it affects only the applicant who applied to the FAA 
for approval of these features on the airplane.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

    The authority citation for these special conditions is as follows:

    Authority:  49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704, 
Pub. L. 113-53, 127 Stat. 584 (49 U.S.C. 44704) note.

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 Aviation, Inc., B200-series 
airplanes, as modified by Innovative Solutions & Support, Inc.

1. Autothrottle System

    In addition to the requirements of Sec. Sec.  23.143, 23.1309, and 
23.1329, the following apply:
    (a) Quick disengagement controls for the autothrust functions must 
be provided for each pilot. The autothrust quick disengagement controls 
must be located on the thrust control levers. Quick disengagement 
controls must be readily accessible to each pilot while operating the 
thrust control levers.
    (b) The effects of a failure of the system to disengage the 
autothrust functions when manually commanded by the pilot must be 
assessed in accordance with the requirements of Sec.  23.1309.
    (c) Engagement or switching of the flight guidance system, a mode, 
or a sensor may not cause the autothrust system to affect a transient 
response that alters the airplane's flight path any greater than a 
minor transient, as defined in paragraph 1(l)(1) of this section.
    (d) Under normal conditions,\4\ the disengagement of any automatic 
control function of a flight guidance system may not cause a transient 
response of the airplane's flight path any greater than a minor 
transient.
---------------------------------------------------------------------------

    \4\ Normal conditions are defined in Advisory Circular 25.1329-
1C, Approval of Flight Guidance Systems. You may find a copy of this 
document at http://rgl.faa.gov/.
---------------------------------------------------------------------------

    (e) Under rare normal and non-normal conditions,\5\ disengagement 
of any automatic control function of a flight guidance system may not 
result in a transient any greater than a significant transient, as 
defined in paragraph 1(l)(2) of this section.
---------------------------------------------------------------------------

    \5\ Rare normal and non-normal conditions are defined in 
Advisory Circular 25.1329-1C, Approval of Flight Guidance Systems. 
You may find a copy of this document at http://rgl.faa.gov/.
---------------------------------------------------------------------------

    (f) The function and direction of motion of each command reference 
control, such as heading select or vertical speed, must be plainly 
indicated on, or adjacent to, each control if necessary to prevent 
inappropriate use or confusion.
    (g) Under any condition of flight appropriate to its use, the 
flight guidance system may not produce

[[Page 66609]]

hazardous loads on the airplane, nor create hazardous deviations in the 
flight path. This applies to both fault-free operation and in the event 
of a malfunction, and assumes the pilot begins corrective action within 
a reasonable period of time.
    (h) When the flight guidance system is in use, a means must be 
provided to avoid excursions beyond an acceptable margin from the speed 
range of the normal flight envelope. If the airplane experiences an 
excursion outside this range, a means must be provided to prevent the 
flight guidance system from providing guidance or control to an unsafe 
speed.
    (i) The flight guidance system functions, controls, indications, 
and alerts must be designed to minimize flight crew errors and 
confusion concerning the behavior and operation of the flight guidance 
system. Means must be provided to indicate the current mode of 
operation, including any armed modes, transitions, and reversions. 
Selector switch position is not an acceptable means of indication. The 
controls and indications must be grouped and presented in a logical and 
consistent manner. The indications must be visible to each pilot under 
all expected lighting conditions.
    (j) Following disengagement of the autothrust function, a caution 
(visual and auditory) must be provided to each pilot.
    (k) During autothrust operation, it must be possible for the 
flightcrew to move the thrust levers without requiring excessive force. 
The autothrust may not create a potential hazard when the flightcrew 
applies an override force to the thrust levers.
    (l) For purposes of this section, a transient is a disturbance in 
the control or flight path of the airplane that is not consistent with 
response to flight crew inputs or environmental conditions.
    (1) A minor transient would not significantly reduce safety margins 
and would involve flightcrew actions that are well within their 
capabilities. A minor transient may involve a slight increase in flight 
crew workload or some physical discomfort to passengers or cabin crew.
    (2) A significant transient may lead to a significant reduction in 
safety margins, an increase in flight crew workload, discomfort to the 
flightcrew, or physical distress to the passengers or cabin crew, 
possibly including non-fatal injuries. Significant transients do not 
require, in order to remain within or recover to the normal flight 
envelope, any of the following:
    (i) Exceptional piloting skill, alertness, or strength.
    (ii) Forces applied by the pilot that are greater than those 
specified in Sec.  23.143(c).
    (iii) Accelerations or attitudes in the airplane that might result 
in further hazard to secured or non-secured occupants.

    Issued in Kansas City, Missouri on December 17, 2018.
Pat Mullen,
Manager, Small Airplane Standards Branch, Aircraft Certification 
Service.
[FR Doc. 2018-28116 Filed 12-26-18; 8:45 am]
 BILLING CODE 4910-13-P