[Federal Register Volume 77, Number 25 (Tuesday, February 7, 2012)]
[Rules and Regulations]
[Page 5990]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-2672]



[[Page 5990]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2011-1108; Special Conditions No. 25-456-SC]


Special Conditions: Learjet Inc., Model LJ-200-1A10 Airplane, 
Pilot-Compartment View Through Hydrophobic Windshield 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 Learjet Model LJ-
200-1A10 airplane. This airplane will have a novel or unusual design 
feature associated with 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: Effective Date: March 8, 2012.

FOR FURTHER INFORMATION CONTACT: Paul Bernado, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., 
Renton, Washington, 98057-3356; telephone (425) 227-1209; facsimile 
(425) 227-1149.

SUPPLEMENTARY INFORMATION:

Background

    On January 11, 2008, Learjet Inc. applied for a type certificate 
for a new Model LJ-200-1A10 airplane. This airplane is 68 feet long 
with a 65-foot wing span and accommodates up to 10 passengers. The LJ-
200-1A10 airplane uses a hydrophobic windshield coating, in lieu of 
windshield wipers, for an unobstructed outside view from the pilot 
compartment.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.17, Learjet Inc. must show that the Model LJ-200-1A10 airplane 
meets the applicable provisions of part 25, as amended by Amendments 
25-1 through 25-123.
    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 LJ-200-1A10 airplane 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 LJ-200-1A10 airplane must comply with the fuel-
vent and exhaust-emission requirements of part 34, and the noise-
certification requirements of part 36, and the FAA must issue a finding 
of regulatory adequacy pursuant to 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 Learjet Model LJ-200-1A10 airplane will incorporate the 
following novel or unusual design features:
    The Model LJ-200-1A10 airplane flight deck design incorporates a 
hydrophobic windshield coating to provide, during precipitation, an 
adequate outside view from the pilot compartment. Sole 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, a 
special condition is required to provide a level of safety equivalent 
to that established by the regulations.

Discussion

    Section 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 heavy-rain 
precipitation at airplane speeds up to 1.5 VSR1. 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 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.

Discussion of Comments

    Notice of proposed special conditions no. 25-11-16-SC for the 
Learjet Model LJ-200-1A10 airplane was published in the Federal 
Register on October 14, 2011 (76 FR 63851). No comments were received, 
and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Model LJ-200-1A10 airplane. Should Learjet Inc. apply at a later date 
for a change to the type certificate to include other type designs 
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 Model LJ-200-1A10 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: 49 106(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 Learjet Inc. Model LJ-200-1A10 
airplanes.
    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.

    Issued in Renton, Washington, on January 30, 2012.
K.C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-2672 Filed 2-6-12; 8:45 am]
BILLING CODE 4910-13-P