
[Federal Register Volume 78, Number 26 (Thursday, February 7, 2013)]
[Rules and Regulations]
[Pages 8961-8962]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-02740]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2012-1200; Special Conditions No. 25-475-SC]


Special Conditions: Embraer S.A., Model EMB-550 Airplane; 
Hydrophobic Coatings in Lieu of Windshield Wipers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Embraer S.A., 
Model EMB-550 airplane. This airplane will have a novel or unusual 
design feature(s) associated with hydrophobic coatings. 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: Effective Date: March 11, 2013.

FOR FURTHER INFORMATION CONTACT: Paul Bernado, FAA, Airplane and Flight 
Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington, 98057-3356; telephone 425-227-1209; facsimile 425-227-1320.

SUPPLEMENTARY INFORMATION:

Background

    On May 14, 2009, Embraer S.A. applied for a type certificate for 
their new Model EMB-550 airplane. The Model EMB-550 airplane is the 
first of a new family of jet airplanes designed for corporate flight, 
fractional, charter, and private owner operations. The aircraft has a 
conventional configuration with low wing and T-tail empennage. The 
primary structure is metal with composite empennage and control 
surfaces. The Model EMB-550 airplane is designed for 8 passengers, with 
a maximum of 12 passengers. It is equipped with two Honeywell HTF7500-E 
medium bypass ratio turbofan engines mounted on aft fuselage pylons. 
Each engine produces approximately 6,540 pounds of thrust for normal 
takeoff. The primary flight controls consist of hydraulically powered 
fly-by-wire elevators, aileron and rudder, controlled by the pilot or 
copilot sidestick.
    The Model EMB-550 airplane will use a hydrophobic coating on the 
windshield in lieu of windshield wipers. The existing regulation, Title 
14, Code of Federal Regulations (14 CFR) 25.773(b)(1), requires a means 
to maintain a sufficiently clear portion of the windshield for both 
pilots to have sufficiently extensive view along the flight path during 
precipitation conditions in heavy rain at speeds up to 1.5 
VSR1. The heavy rain and high speed conditions in the rule 
do not necessarily represent the limiting condition for this new 
technology. For example, airflow over the windshield may be necessary 
to remove moisture, but may not be adequate to maintain a sufficiently 
clear area of the windshield in low speed flight or during surface 
operations. Alternatively, airflow over the windshield may be disturbed 
during critical times such as the approach to land, where the airplane 
is at higher-than-normal pitch angle.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Embraer S.A. must show that 
the Model EMB-550 airplane meets the applicable provisions of part 25, 
as amended by Amendments 25-1 through 25-127 thereto.
    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 Model 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 or similar 
novel or unusual design feature, the 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 S.A. Model 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 and the FAA must 
issue a finding of regulatory adequacy under Sec.  611 of Public Law 
92-574, the ``Noise Control Act of 1972.''
    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.  21.17(a)(2).

Novel or Unusual Design Features

    The Embraer S.A. Model EMB-550 airplane will incorporate the 
following novel or unusual design features: The Model EMB-550 airplane 
has a hydrophobic coating on the windshield to provide adequate pilot 
compartment view in precipitation in lieu of windshield wipers.

Discussion

    14 CFR 25.773(b)(1) requires a means to maintain a clear portion of 
the windshield for both pilots to have a sufficiently extensive view 
along the flight path during precipitation conditions. The regulations 
require this means to maintain such an area during precipitation in 
heavy rain at speeds up to 1.5 VSR1. The requirement that 
the means to maintain a clear area of forward vision must function at 
high speeds and high precipitation rates is based on the use of 
windshield wipers as the means to maintain an adequate area of clear 
vision in precipitation conditions. The requirement in 14 CFR 
121.313(b), and in 14 CFR 125.213(b), to provide ``a windshield wiper 
or equivalent for each pilot station'' has remained unchanged since at 
least 1953.
    The effectiveness of windshield wipers to maintain an area of clear 
vision normally degrades as airspeed and precipitation rates increase. 
It is assumed that because high speeds and high precipitation rates 
represent limiting conditions for windshield wipers, they will also be 
effective at lower speeds and precipitation levels. Accordingly, Sec.  
25.773(b)(1)(i) does not require maintenance of a clear area of forward 
vision at lower speeds or lower precipitation rates.
    A forced airflow blown directly over the windshield has also been 
used to maintain an area of clear vision in precipitation. The limiting 
conditions

[[Page 8962]]

for this technology are comparable to those for windshield wipers. 
Accordingly, introduction of this technology did not present a need for 
special conditions to maintain the level of safety embodied in the 
existing regulations.
    Hydrophobic windshield coatings may depend to some degree on 
airflow directly over the windshield to maintain a clear vision area. 
The heavy rain and high-speed conditions specified in the current rule 
do not necessarily represent the limiting conditions for this new 
technology. For example, airflow over the windshield, which may be 
necessary to remove moisture from the windshield, may not be adequate 
to maintain a sufficiently clear area of the windshield in low speed 
flight or during ground operations. Alternatively, airflow over the 
windshield may be disturbed during such critical times as the approach 
to land, where the airplane is at a higher than normal pitch attitude. 
In these cases, areas of airflow disturbance or separation on the 
windshield could cause failure to maintain a clear vision area on the 
windshield.
    In addition to potentially depending on airflow to function 
effectively, hydrophobic coatings may also be dependent on water 
droplet size for effective precipitation removal. For example, 
precipitation in the form of a light mist may not be sufficient for the 
coating's properties to result in maintaining a clear area of vision.
    In summary, the current regulations identify speed and 
precipitation rate requirements that represent limiting conditions for 
windshield wipers and blowers, but not for hydrophobic coatings, so it 
is necessary to issue special conditions to maintain the level of 
safety represented by the current regulations.
    These special conditions provide an appropriate safety standard for 
the hydrophobic coating technology as the means to maintain a clear 
area of vision by requiring it to be effective at low speeds and 
precipitation rates as well as the higher speeds and precipitation 
rates identified in the current regulation.

Discussion of Comments

    Notice of proposed special conditions No. 25-12-07-SC for the 
Embraer S.A. Model EMB-550 airplanes was published in the Federal 
Register on November 9, 2012, (77 FR 67308). No comments were received, 
and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Embraer S.A. Model EMB-550 airplane. Should Embraer S.A. 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 
special conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on one model of airplanes. It is not a rule of general applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    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 Embraer S.A. Model EMB-550 airplanes.

Hydrophobic Coatings in Lieu of Windshield Wipers

    The airplane must have a means to maintain a clear portion of the 
windshield, during precipitation conditions, enough for both pilots to 
have a sufficiently extensive view along the ground or flight path in 
normal taxi and flight attitudes of the airplane. This means must be 
designed to function, without continuous attention on the part of the 
flightcrew, in conditions from light misting precipitation to heavy 
rain at speeds from fully stopped in still air, to 1.5 VSR1 
with lift and drag devices retracted.

    Issued in Renton, Washington, on February 4, 2013.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-02740 Filed 2-6-13; 8:45 am]
BILLING CODE 4910-13-P


