Document ID: FAA-2013-0772-0003
Agency: faa
Document Type: Proposed Rule
Title: Special Conditions: Embraer EMB-550 Airplane; Flight Envelope Protection: Normal Load Factor (g) Limiting
Posted Date: 2019-04-08T04:00Z

[Federal Register Volume 84, Number 67 (Monday, April 8, 2019)]
[Proposed Rules]
[Pages 13838-13840]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-06647]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-0772; Notice No. 25-19-01-SC]

Special Conditions: Embraer EMB-550 Airplane; Flight Envelope 
Protection: Normal Load Factor (g) Limiting

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes an amendment to special conditions for 
the Embraer EMB-550 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. This 
design feature is associated with an electronic flight control system 
that prevents the pilot from inadvertently or intentionally exceeding 
the positive or negative airplane limit load factor. The applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for this design feature. These proposed 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: Send comments on or before April 29, 2019.

ADDRESSES: Send comments identified by Docket No. FAA-2013-0772 using 
any of the following methods:
     Federal eRegulations Portal: Go to http://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.
    Privacy: The FAA will post all comments it receives, without 
change, to http://www.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).
    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 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: 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: 

[[Page 13839]]

Comments Invited

    We invite 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.
    We will consider all comments we receive by the closing date for 
comments. We may change these special conditions based on the comments 
we receive.

Background

    On August 9, 2016, Embraer applied for a change to Type Certificate 
No. TC00062IB to include additional flexibility to the normal load 
factor limit on the Model EMB-550 airplane, by amending the existing 
Model EMB-550 Special Conditions No. 25-520-SC as a result of 
harmonization efforts in the Flight Test Harmonization Working Group 
(FTHWG). The Embraer EMB-550 airplane, currently approved under Type 
Certificate No. TC00062IB, is a twin-engine, transport category 
airplane with a maximum takeoff weight of 42,857 pounds. The EMB-550 
has a maximum seating capacity of 12 passengers.
    The Model EMB-550 flight control system design incorporates normal 
load factor limiting on a full-time basis that will prevent the pilot 
from inadvertently or intentionally exceeding the positive or negative 
airplane limit load factor. This feature is considered novel and 
unusual in that the current regulations do not provide standards for 
maneuverability and controllability evaluations for such systems.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Embraer must show that the EMB-550 airplane, as changed, 
continues to meet the applicable provisions of the regulations listed 
in Type Certificate No. TC00062IB 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 Embraer EMB-550 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 Embraer EMB-550 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 Embraer EMB-550 airplane will incorporate the following novel 
or unusual design features:
    The Model EMB-550 flight control system design incorporates normal 
load factor limiting on a full-time basis that will prevent the pilot 
from inadvertently or intentionally exceeding the positive or negative 
airplane limit load factor. This feature is considered novel and 
unusual in that the current regulations do not provide standards for 
maneuverability and controllability evaluations for such systems.

Discussion

    The normal load factor limit on the Model EMB-550 is unique in that 
traditional airplanes with conventional flight control systems 
(mechanical linkages) are limited in the pitch axis only by the 
elevator surface area and deflection limit. The elevator control power 
is normally derived for adequate controllability and the 
maneuverability at the most critical longitudinal pitching moment. The 
result is that traditional airplanes have a significant portion of the 
flight envelope where maneuverability in excess of limit structural 
design values is possible. The Model EMB-550 because of the normal load 
factor limit does not have this excess maneuverability.
    Title 14, Code of Federal Regulations (14 CFR) part 25 does not 
specify requirements for demonstrating maneuver control that impose any 
handling qualities requirements beyond the design limit structural 
loads. Nevertheless, some pilots are accustomed to the availability of 
this excess maneuver capacity in case of extreme emergency such as 
upset recoveries or collision avoidance.
    As a result of harmonization efforts with other civil aviation 
authorities through the Flight Test Harmonization Working Group 
(FTHWG), the FAA is including additional flexibility in maneuverability 
limits by amending the existing Model EMB-550 Special Conditions No. 
25-520-SC. This additional flexibility allows for reduced 
maneuverability limits beyond Vmo/Mmo. The existing special conditions 
are otherwise unchanged.
    The proposed 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 
Embraer EMB-550 airplane. Should Embraer 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.
    Certification of the Embraer EMB-550 airplane is currently 
scheduled for April 2019. The substance of these special conditions has 
been subject to the notice and public comment procedure in several 
prior instances. Therefore, because a delay would significantly affect 
the applicant's installation of the system and the certification of the 
airplane, we are shortening the public comment period to 20 days.

Conclusion

    This action affects only certain novel or unusual design features 
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 Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for Embraer EMB-550 airplanes.

Flight Envelope Protection: Normal Load Factor (g) Limiting

    1. To meet the intent of adequate maneuverability and 
controllability required

[[Page 13840]]

by Sec.  25.143(a), and in addition to the requirements of Sec.  
25.143(a) and in the absence of other limiting factors, the 
following special conditions are proposed based on Sec.  25.333(b):
    a. The positive limiting load factor must not be less than:
    (1) 2.5g for the normal state of the electronic flight control 
system with the high lift devices retracted up to Vmo/Mmo. The 
positive limiting load factor may be gradually reduced down to 2.25g 
above Vmo/Mmo.
    (2) 2.0g for the normal state of the electronic flight control 
system with the high lift devices extended.
    b. The negative limiting load factor must be equal to or more 
negative than:
    (1) Minus 1.0g for the normal state of the electronic flight 
control system with the high lift devices retracted.
    (2) 0.0g for the normal state of the electronic flight control 
system with high lift devices extended.
    c. Maximum reachable positive load factor wings level may be 
limited by the characteristics of the electronic flight control 
system or flight envelope protections (other than load factor 
protection) provided that:
    (1) The required values are readily achievable in turns, and
    (2) Wings level pitch up responsiveness is satisfactory.
    d. Maximum achievable negative load factor may be limited by the 
characteristics of the electronic flight control system or flight 
envelope protections (other than load factor protection) provided 
that:
    (1) Pitch down responsiveness is satisfactory, and
    (2) From level flight, 0g is readily achievable or 
alternatively, a satisfactory trajectory change is readily 
achievable at operational speeds. For the FAA to consider a 
trajectory change as satisfactory, the applicant should propose and 
justify a pitch rate that provides sufficient maneuvering capability 
in the most critical scenarios.
    e. Compliance demonstration with the above requirements may be 
performed without ice accretion on the airframe.
    f. These special conditions do not impose an upper bound for the 
normal load factor limit, nor does it require that the limiter 
exist. If the limit is set at a value beyond the structural design 
limit maneuvering load factor ``n'' of Sec. Sec.  25.333(b), 
25.337(b) and 25.337(c), there should be a very obvious positive 
tactile feel built into the controller so that it serves as a 
deterrent to inadvertently exceeding the structural limit.

    Issued in Des Moines, Washington.
Suzanne Masterson,
Acting Manager, Transport Standards Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2019-06647 Filed 4-5-19; 8:45 am]
 BILLING CODE 4910-13-P