[Federal Register Volume 71, Number 133 (Wednesday, July 12, 2006)]
[Proposed Rules]
[Pages 39235-39237]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-10894]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM348; Notice No. 25-06-07-SC]


Special Conditions: Dassault Aviation Model Falcon 7X Airplane, 
Windshield Coating in Lieu of Wipers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for the Dassault 
Aviation Model Falcon 7X airplane. This airplane will have a novel or 
unusual design feature(s) associated with use of a hydrophobic coating, 
rather than windshield wipers, as the means to maintain a clear portion 
of the windshield during precipitation conditions, as required by the 
airworthiness standards for transport category airplanes. 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: We must receive your comments by August 28, 2006.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM348, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356. You may deliver two copies to the Transport 
Airplane

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Directorate at the above address. You must mark your comments: Docket 
No. NM348 You can inspect comments in the Rules Docket weekdays, except 
Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: John McConnell, Airplane and Flight 
Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-1365; facsimile (425) 227-
1320, e-mail [email protected].

SUPPLEMENTARY INFORMATION:

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 ask 
that you send us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning these special conditions. You can inspect the docket before 
and after the comment closing date. If you wish to review the docket in 
person, go to the address in the ADDRESSES section of this preamble 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change 
these special conditions based on the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it back to you.

Background

    On June 4, 2002, Dassault Aviation applied for a type certificate 
for its new Model Falcon 7X airplane. The Model Falcon 7X is a 19 
passenger transport category airplane, powered by three aft mounted 
Pratt & Whitney PW307A high bypass ratio turbofan engines. Operation of 
the airplane is accomplished using a fly-by-wire (FBW) primary flight 
control system. This will be the first application of a FBW primary 
flight control system in a private/corporate use airplane.
    The Dassault Aviation Model Falcon 7X flightdeck design 
incorporates a hydrophobic coating to provide adequate pilot 
compartment view in the presence of precipitation. Primary reliance on 
such a coating, without windshield wipers, constitutes a novel or 
unusual design feature for which the applicable airworthiness 
regulations do not contain adequate or appropriate safety standards. 
Therefore, special conditions are required that provide the level of 
safety equivalent to that established by the regulations.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Dassault Aviation must show 
that the Model Falcon 7X airplane meets the applicable provisions of 
part 25, as amended by Amendment 25-1 through Amendment 25-108 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 Falcon 7X because of a novel 
or unusual design feature, special conditions are prescribed under the 
provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model Falcon 7X 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 Sec.  11.19, under 
Sec.  11.38, and they become part of the type certification basis under 
Sec.  21.17(a)(2).
    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.

Novel or Unusual Design Features

    The Model Falcon 7X will incorporate the following novel or unusual 
design feature:
    Hydrophobic windshield coating as the primary means to maintain a 
clear portion of the windshield, during precipitation conditions, 
sufficient for both pilots to have a sufficiently extensive view along 
the flight path.

Discussion

    Section 25.773(b)(1) requires that both pilots of a transport 
category airplane be provided a means to maintain a sufficiently clear 
portion of the windshield during precipitation conditions, and that 
this clear portion of the windshield must have a sufficiently extensive 
view along the flight path. The regulations require this means to 
maintain such an area during precipitation in heavy rain at speeds up 
to 1.5 VSR1.
    This requirement has existed in principle since 1953 in Part 4b of 
the Civil Air Regulations (CAR). Section 4b.351(b)(1) of CAR 4b 
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 VS1, 
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 VS1 to 1.5 VSR1 to 
accommodate the redefinition of the reference stall speed from the 
minimum speed in the stall, VS1, to greater than or equal to 
the 1-g stall speed, VSR1, as the 1-g stall speed. As noted 
in the preamble to the final rule for that amendment, the reduced 
factor of 1.5 on VSR1 is to maintain approximately the same 
speed as the 1.6 factor on VS1.
    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 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

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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. These are the only new or 
changed requirements relative to those in Sec.  25.773(b)(1) at 
Amendment 25-108.

Applicability

    As discussed above, these special conditions are applicable to the 
Model Falcon 7X. Should Dassault Aviation 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 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(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 Dassault Aviation Model Falcon 7X airplanes.

Pilot Compartment View--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 flight path in normal 
flight attitudes of the airplane. This means must be designed to 
function, without continuous attention on the part of the crew, 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 July 3, 2006.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E6-10894 Filed 7-11-06; 8:45 am]
BILLING CODE 4910-13-P