[Federal Register Volume 84, Number 158 (Thursday, August 15, 2019)]
[Unknown Section]
[Pages 41597-41599]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-17570]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2019-0617; Special Conditions No. 23-294-SC]


Special Conditions: Pilatus Aircraft Ltd. Model PC-12/47E 
Airplanes; Autothrust System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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

SUMMARY: These special conditions are issued for the Pilatus Aircraft 
Ltd. Model PC-12/47E airplane. This airplane will have a novel or 
unusual design feature associated with the use of 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 that the 
Administrator considers necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards.

DATES: The effective date of these special conditions is August 15, 
2019.
    The FAA must receive your comments by September 16, 2019

ADDRESSES: Send comments identified by docket number FAA-2019-0617 
using any of the following methods:
    [squ] Federal eRegulations Portal: Go to http://www.regulations.gov 
and follow the online instructions for sending your comments 
electronically.
    [squ] 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.
    [squ] Hand Delivery of 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.
    [squ] Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://regulations.gov, including any personal information 
the commenter provides. Using the search function of the docket 
website, anyone can find and read the electronic form of all comments 
received into any FAA docket, including the name of the individual 
sending the comment (or signing the comment for an association, 
business, labor union, etc.). DOT's complete Privacy Act Statement can 
be found in the Federal Register published on April 11, 2000 (65 FR 
19477-19478), as well as at http://DocketsInfo.dot.gov.
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov at any time. Follow the online instructions 
for accessing the docket or go to the 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: Jeff Pretz, AIR-691, Small Airplane 
Standards Branch, Policy & Innovation Division, Aircraft Certification 
Service, Federal Aviation Administration, 901 Locust, Room 301, Kansas 
City, MO 64106; telephone (816) 329-3239; facsimile (816) 329-4090.

SUPPLEMENTARY INFORMATION: 

Reason for No Prior Notice and Comment Before Adoption

    The FAA has determined, in accordance with 5 U.S. Code Sec. Sec.  
553(b)(3)(B) and 553(d)(3), that notice and opportunity for prior 
public comment hereon are unnecessary because substantially identical 
special conditions have been subject to the public comment process in 
several prior instances such that the FAA is satisfied that new 
comments are unlikely. For the same reason, the FAA finds that good 
cause exists for making these special conditions effective upon 
issuance. The FAA is requesting comments to allow interested persons to 
submit views that may not have been submitted in response to the prior 
opportunities for comment.

------------------------------------------------------------------------
        Special conditions No.               Company/airplane model
------------------------------------------------------------------------
23-291-SC \1\........................  Innovation Solutions & Support,
                                        Inc.; Textron Aviation, Inc./
                                        Model B200.
23-283-SC \2\........................  Pilatus Aircraft Ltd./Model PC-
                                        24.
23-272-SC \3\........................  Cirrus Aircraft Corporation/Model
                                        SF-50.
------------------------------------------------------------------------

Comments Invited
---------------------------------------------------------------------------

    \1\ https://www.federalregister.gov/d/2018-28116.
    \2\ https://www.federalregister.gov/d/2017-14938.
    \3\ https://federalregister.gov/a/2015-31058.
---------------------------------------------------------------------------

    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 
asks that you send two copies of written comments.
    The FAA will consider all comments received on or before the 
closing date for comments. The FAA will consider comments filed late if 
it is possible to do so without incurring expense or delay. The FAA may 
change these special conditions based on the comments received.

Background

    On March 9, 2017, Pilatus Aircraft Ltd. (Pilatus) applied for FAA 
validation of its change to Type Certificate No. A78EU \4\ for 
installation of an autothrust system (ATS)--also known as an 
autothrottle system--in the Model PC-12/47E airplane. The Model PC-12/
47E is a normal category, metallic, pressurized, low-wing, monoplane 
that seats nine passengers and two flightcrew. A single Pratt & Whitney

[[Page 41598]]

PT6E-67XP \5\ engine driving a five bladed variable pitch constant 
speed Hartzell propeller powers the airplane. The airplane has 
retractable tricycle landing gear, a Honeywell APEX avionics suite, and 
a maximum takeoff weight of 10,450 pounds.
---------------------------------------------------------------------------

    \4\ See http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/EED2BA802A848862583360061A683?OpenDocument&Highlight=a78eu.
    \5\ As of this special condition publishing date, engine 
approval is in process. The final engine model number will be 
updated on Type Certification Data Sheet A78EU upon engine approval 
completion.
---------------------------------------------------------------------------

    The installation of an ATS in the Model PC-12/47E is intended to 
reduce pilot workload. The ATS is useable in all phases from takeoff to 
approach. The system includes torque and airspeed management capability 
along with monitors to prevent the system from exceeding critical 
engine or airspeed limits. Throttle movement is provided by a servo, 
which moves the throttle lever. The servo can be overridden by pilot 
movement of the throttle and disengages upon selection of the A/T 
disconnect switch on the throttle.
    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. 14 CFR 
25.1329, amendment 25-119, addresses these concerns for transport 
airplanes. 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 14 CFR 21.101, Pilatus must show that the 
Model PC-12/47E airplane, as changed, continues to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. A78EU 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.'' In addition to the original type 
certification basis, the FAA has determined that the Model PC-12/47E 
must also comply with Sec.  23.905(d) as amended by amendment 23-59, 
Sec.  23.1306 as amended by amendment 23-61, Sec.  23.1308 as amended 
by amendment 23-57, and Sec. Sec.  23.1309 and 23.1310 as amended by 
amendment 23-62.
    If the Administrator finds that the applicable airworthiness 
regulations in part 23 do not contain adequate or appropriate safety 
standards for the Model PC-12/47E airplane because of a novel or 
unusual design feature, special conditions are prescribed under the 
provisions of Sec.  21.16.
    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.  21.101.
    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, the FAA would apply these special conditions to 
the other model.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model PC-12/47E 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; and the FAA must issue a 
finding of regulatory adequacy under Sec.  611 of Public Law 92-574, 
the ``Noise Control Act of 1972.''

Novel or Unusual Design Features

    The Model PC-12/47E airplane will incorporate the following novel 
or unusual design features:
    An ATS, which provides commands to a servo attached to the throttle 
lever that automatically controls engine thrust. The ATS can be 
operated to control torque or airspeed.

Discussion

    The part 23 airworthiness regulations in the type certification 
basis do not contain appropriate safety standards for this design 
feature. However, part 25 regulations contain appropriate airworthiness 
standards; therefore, these special conditions are derived from 14 CFR 
25.1329, ``Flight guidance system,'' applicable to autothrust systems.

Applicability

    These special conditions are applicable to the Model PC-12/47E 
airplane. Should Pilatus apply at a later date for a change to the type 
certificate to include another model incorporating the same novel or 
unusual design feature, the FAA would apply these special conditions to 
that model as well.

Conclusion

    This action affects only a certain novel or unusual design feature 
on the Model PC-12/47E airplane. It is not a rule of general 
applicability.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702; 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 Pilatus Aircraft Ltd. Model PC-12/47E 
airplanes.

Autothrust 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 function 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 function 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 (l)(1) of these special 
conditions.
    (d) Under normal conditions, 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.
    (e) Under rare normal and non-normal conditions, 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 (l)(2) of these special conditions.
    (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

[[Page 41599]]

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 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 that 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 flightcrew 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 
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 these special conditions, a transient is a 
disturbance in the control or flight path of the airplane that is not 
consistent with response to flightcrew 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 
flightcrew 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 flightcrew 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 which 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 August 1, 2019.
Pat Mullen,
Manager, Small Airplane Standards Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2019-17570 Filed 8-14-19; 8:45 am]
BILLING CODE 4910-13-P


