Rule2022-00129
Special Conditions: Dassault Aviation Model Falcon 6X Airplane; Hydrophobic Windshield Coatings in Lieu of Windshield Wipers
Primary source
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Published
January 10, 2022
Effective
January 10, 2022
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
These amended special conditions are issued for the Dassault Model Falcon 6X 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 hydrophobic windshield coatings in lieu of windshield wipers. 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.
Full Text
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<title>Federal Register, Volume 87 Issue 6 (Monday, January 10, 2022)</title>
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[Federal Register Volume 87, Number 6 (Monday, January 10, 2022)]
[Rules and Regulations]
[Pages 1066-1068]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-00129]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2014-1075; Special Conditions No. 25-599A-SC]
Special Conditions: Dassault Aviation Model Falcon 6X Airplane;
Hydrophobic Windshield Coatings in Lieu of Windshield Wipers
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions, amendment.
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SUMMARY: These amended special conditions are issued for the Dassault
Model Falcon 6X 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 hydrophobic windshield coatings in lieu of windshield
wipers. 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: This action is effective on Dassault on January 10, 2022.
FOR FURTHER INFORMATION CONTACT: Paul Pellicano, AIR-625, Performance
and Environment Section, Technical Innovation Policy Branch, Policy and
Innovation Division, Federal Aviation Administration, 1701 Columbia
Avenue, College Park, GA 30337; telephone and fax 404-474-5558, email
<a href="/cdn-cgi/l/email-protection#5e0e3f2b32700e3b3232373d3f30311e383f3f70393128"><span class="__cf_email__" data-cfemail="c898a9bda4e698ada4a4a1aba9a6a788aea9a9e6afa7be">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
On July 1, 2012, Dassault Aviation applied for a type certificate
for their new Model Falcon 5X airplane. Special conditions were issued
for that design on September 15, 2015 (80 FR 55226). However, Dassault
has decided not to release an airplane under the model designation
Falcon 5X, instead choosing to change that model designation to Falcon
6X.
In February of 2018, due to engine supplier issues, Dassault
extended the type certificate application date for their Model Falcon
5X airplane under new Model Falcon 6X. This amendment to the original
special conditions reflects the model-name change. This airplane is a
twin-engine business jet with seating for 19 passengers and a maximum
takeoff weight of 77,460 pounds. The Dassault Model Falcon 6X airplane
design remains unchanged from the Model Falcon 5X in all material
respects other than different engines.
Type Certification Basis
Under the provisions of Title 14, Code of Federal Regulations (14
CFR) 21.17, Dassault Aviation must show that the Model Falcon 6X
airplane meets the applicable provisions of part 25, as amended by
Amendments 25-1 through 25-146.
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 Dassault Model Falcon 6X 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
[[Page 1067]]
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, 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 Model Falcon 6X 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. 21.17(a)(2).
Novel or Unusual Design Features
The Dassault Model Falcon 6X airplane flight deck design
incorporates a hydrophobic coating as a primary means to provide
adequate windshield view in the presence of atmospheric precipitation.
Reliance on such a coating, in lieu of wipers, constitutes a novel or
unusual design feature for which the applicable airworthiness
regulations do not contain adequate or appropriate safety standards.
Discussion
Section 25.773(b)(1) requires a means to maintain a clear portion
of the windshield for both pilots operating a transport-category
airplane to have a sufficiently extensive view along the flight path
during precipitation conditions. The regulations require this means to
maintain such an area of clear vision during heavy-rain precipitation
at airplane speeds up to 1.5 V<INF>SR1</INF>.
This requirement has existed in principle since 1953 in part 4b of
the ``Civil Air Regulations'' (CAR). Section 4b.351(b)(1) required that
``Means shall be provided for maintaining a sufficient portion of the
windshield clear so that both pilots are afforded a sufficiently
extensive view along the flight path in all normal flight attitudes of
the airplane. Such means shall be designed to function under the
following conditions without continuous attention on the part of the
crew: (i) In heavy rain at speeds up to 1.6 V<INF>S1</INF>, flaps
retracted.''
Effective December 26, 2002, Amendment 25-108 changed the speed for
effectiveness of the means to maintain an area of clear vision from up
to 1.6 V<INF>S1</INF> to 1.5 V<INF>SR1</INF> to accommodate the
redefinition of the reference stall speed from the minimum speed in the
stall, V<INF>S1</INF>, to greater than or equal to the 1g stall speed,
V<INF>SR1</INF>. As noted in the preamble to the final rule for that
amendment, the reduced factor of 1.5 on V<INF>SR1</INF> is to maintain
approximately the same speed as the 1.6 factor on V<INF>S1</INF>.
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 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 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 to maintain a clear-vision area. The heavy rain and high speed
conditions specified in the current rule do not necessarily represent
the limiting condition 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-vision
area of the windshield in low-speed flight or during surface
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.
The current regulations identify speed and precipitation rate
requirements that represent limiting conditions for windshield wipers
and blowers, but not for hydrophobic coatings. Likewise, 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 the coating to be effective at low speeds
and low precipitation rates, as well as at the higher speeds and
precipitation rates identified in the current regulation.
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.
Discussion of Comments
The FAA issued Final special conditions, request for comment
Special Conditions No. 25-599-SC for the Dassault Model Falcon 5X
airplane, which was published in the Federal Register on September 15,
2015 (80 FR 55226). No comments were received, and the special
conditions are adopted as proposed, with amendments.
Applicability
As discussed above, these special conditions are applicable to the
Dassault Model Falcon 6X airplane. Should Dassault 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 the Dassault Model Falcon 6X airplane. 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(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 Dassault Model Falcon 6X airplanes.
[[Page 1068]]
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 V<INF>SR1</INF>
with lift and drag devices retracted.
Issued in Kansas City, Missouri, on January 4, 2022.
Patrick R. Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation
Division, Aircraft Certification Service.
[FR Doc. 2022-00129 Filed 1-7-22; 8:45 am]
BILLING CODE 4910-13-P
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</html>Indexed from Federal Register on January 10, 2022.
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