[Federal Register: October 31, 2006 (Volume 71, Number 210)]
[Proposed Rules]
[Page 63723-63725]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr31oc06-20]
[[Page 63723]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM358; Notice No. 25-06-12-SC]
Special Conditions: Gulfstream Aerospace Corporation, Model GV,
GV-SP, and GIV-X Airplanes; Windshield Coating in Lieu of Wipers
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special condition.
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SUMMARY: This action proposes a special condition for the Gulfstream
Aerospace Corporation Model GV, GV-SP, and GIV-X airplanes. These
airplanes will have a novel or unusual design feature(s) associated
with use of a hydrophobic windshield 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. This proposed special condition
contains 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 November 20, 2006.
ADDRESSES: You must mail two copies of your comments to: Federal
Aviation Administration, Transport Airplane Directorate, Attn: Rules
Docket (ANM-113), Docket No. NM358, 1601 Lind Avenue SW., Renton,
Washington, 98057-3356. You may deliver two copies to the Transport
Airplane Directorate at the above address. You must mark your comments:
Docket No. NM358. 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, 98057-3356; telephone (425) 227-1365; facsimile (425) 227-
1320, e-mail john.mcconnell@faa.gov.
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 condition, 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 this special condition. 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 7:30 a.m. and 4 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
this special condition 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 December 19, 2005, Gulfstream Aerospace Corporation applied for
a change to Type Certificate No. A12EA to use a hydrophobic windshield
coating as the sole means of providing adequate pilot compartment view
in the presence of precipitation for Gulfstream Model GV, GV-SP and
GIV-X airplanes. The Gulfstream Model GV, GV-SP and GIV-X airplanes are
currently approved under Type Certificate No. A12EA. The Model GV
airplane is powered by two BMW-Rolls Royce Deutschland BR700-710A1-10
engines, operates with a two person flightcrew, and has the capacity to
carry 19 passengers. The Model GV-SP airplane is powered by two BMW-
Rolls Royce Deutschland BR700-710C4-11 engines, operates with a two
person flightcrew, and has the capacity to carry 19 passengers. The
Model GIV-X airplane is powered by two Rolls Royce Tay Mark 611-8C
engines, operates with a two person flightcrew, and has the capacity to
carry 19 passengers.
Type Certification Basis
Under the provisions of Sec. 21.101, Gulfstream Aerospace
Corporation must show that the Model GV, GV-SP and GIV-X airplanes, as
changed, continue to meet the applicable provisions of the regulations
incorporated by reference in Type Certificate No. A12EA, 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.''
The regulations incorporated by reference in Type Certificate No.
A12EA include:
For Model GV airplanes--part 25, effective February 1,
1965, Amendment 25-1 through Amendment 25-81, with exceptions.
For Model GV-SP airplanes--part 25, effective February 1,
1965, Amendment 25-1 through Amendment 25-98.
For Model GIV-X airplanes--part 25, effective February 1,
1965, Amendment 25-1 through Amendment 25-101, with exceptions.
In addition, the certification basis includes other regulations,
special conditions and exemptions that are not relevant to this
proposed special condition.
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 GV, GV-SP and GIV-X
airplanes 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 GV, GV-SP and GIV-X airplanes 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 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 or similar
novel or unusual design feature, or should any other model already
included on the same type certificate be modified to incorporate 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 Gulfstream Model G-V, GV-SP and GIV-X flightdeck designs
[[Page 63724]]
incorporate a hydrophobic windshield coating to provide adequate pilot
compartment view in the presence of precipitation. Sole reliance on
such a coating, without windshield wipers or a windshield blower,
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.
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, 1990, Amendment 25-108
changed the criterion for effectiveness of the means to maintain an
area of clear vision from 1.6 VS1 to 1.5 VSR1 to
accommodate the redefinition of the reference stall speed as the 1-g
stall speed. As noted in the preamble to the final rule for that
amendment, the 7 percent decrease in the speed value offsets a
corresponding increase in the reference stall speed associated with the
use of VSR1 rather than 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 airflow 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 air stream blown 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 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 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.
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 sole 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, this special condition is applicable to
Gulfstream Model GV, GV-SP and GIV-X airplanes. Should Gulfstream
Aerospace Corporation 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 condition would apply to that model
as well.
The substance of this special condition has been subject to the
notice and public comment procedure in several prior instances.
Therefore, because a delay would significantly affect scheduled
airplane deliveries, we are shortening the public comment period to 20
days.
Conclusion
This action affects only certain novel or unusual design features
on Gulfstream Model GV, GV-SP, and GIV-X 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 Proposed Special Condition
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special condition as part of the type certification basis for
Gulfstream Aerospace Corporation Model GV, GV-SP, and GIV-X 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 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
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.
[[Page 63725]]
Issued in Renton, Washington, on October 23, 2006.
Kalene C. Yanamura,
Acting Manager,Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E6-18288 Filed 10-30-06; 8:45 am]
BILLING CODE 4910-13-P