
[Federal Register Volume 76, Number 3 (Wednesday, January 5, 2011)]
[Proposed Rules]
[Pages 490-491]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-33310]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 77

[Docket No: FAA 2010-1326]


Marking Meteorological Evaluation Towers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Proposed revision to Advisory Circular; request for comments.

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SUMMARY: The FAA is considering revising its current Advisory Circular 
on Obstruction Marking and Lighting to include guidance for 
Meteorological Evaluation Towers (METs). These towers are erected in 
remote and rural areas, often are less than 200 feet above ground level 
(AGL), and fall outside of FAA regulations governing tall structures 
and their impact on navigable airspace. The proposed marking guidance 
would enhance the conspicuity of the towers and address the safety 
related concerns of low level agricultural operations. The FAA seeks 
comment on the proposed guidance.

DATES: Comments must be received on or before February 4, 2011.

ADDRESSES: You may send comments identified by docket number FAA 2010-
1326 using any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send Comments to Docket Operations, M-30; U.S. 
Department of Transportation, 1200 New Jersey Avenue, SE., West 
Building Ground Floor, Room W12-140, West Building Ground Floor, 
Washington, DC 20590-0001.
     Hand Delivery: Take comments to Docket Operations in Room 
W12-140 of the West Building Ground Floor at 1200 New Jersey Avenue, 
SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays.
     Fax: (202) 493-2251.

FOR FURTHER INFORMATION CONTACT: Sheri Edgett-Barron, Obstruction 
Evaluation Services, Air Traffic Organization, AJV-15, Federal Aviation 
Administration, 800 Independence Avenue, SW., Washington, DC 20591; 
telephone: (202) 267-8783; e-mail: sheri.edgett-baron@faa.gov.

SUPPLEMENTARY INFORMATION:

14 CFR Part 77

    Title 49 of the United States Code (U.S.C.), section 40103(a)(1), 
provides that the ``United States Government has exclusive sovereignty 
of airspace of the United States.'' Paragraph (b) of this section 
directs the FAA to ``develop plans and policy for the use of the 
navigable airspace and assign by regulation or order the use of the 
airspace necessary to ensure the safety of aircraft and the efficient 
use of the airspace.''
    In recognition of the threat tall structures can pose to aviation 
safety, 49 U.S.C. 44718 directed the FAA to promulgate regulations 
requiring notice of proposed structures or alterations of existing 
structures when the notice will promote safety in air commerce and the 
efficient use and preservation of the navigable airspace and of airport 
traffic capacity at public-use airports. (14 CFR part 77.) The agency 
was further directed to study such structures and determine the extent 
of any adverse impacts on the safe and efficient use of the airspace, 
facilities or equipment.

[[Page 491]]

    Consistent with the above statutory and regulatory framework, the 
FAA has adopted policy to establish the standards for which the FAA 
identifies ``obstructions'' and ``hazards'' in the navigable airspace 
in furtherance of its responsibilities to manage the navigable airspace 
safely and efficiently. See 14 CFR part 77, and FAA Order 7400.2, 
Procedures for Handling Airspace Matters. The FAA issues a 
determination advising whether the structure would be a hazard to air 
navigation. The FAA may condition its determination of no hazard with 
the structure appropriately being marked and lighted, as specified in 
the determination. FAA criteria for marking and lighting of tall 
structures are found in Advisory Circular No. 70/7460-1, Obstruction 
Marking and Lighting.
    Unless within the vicinity of an airport,\1\ proponents of new 
structures or alterations of existing structures must file notice with 
the FAA for ``any construction or alteration of more than 200 feet in 
height above the ground level at its site.'' 14 CFR 77.13(a)(1). 
Consequently, as the FAA does not study these structures there is no 
FAA determination that would specify the marking of these structures.
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    \1\ 14 CFR 77.13(a), paragraphs (2), (3), (4) and (5) are not 
relevant to this issue.
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Background

    The emphasis to discover sources of renewable energy in the United 
States has prompted individuals and companies to explore all means of 
energy generation. Wind energy, converted into electrical energy by 
wind turbines, is widely pursued as a viable alternative. In order to 
determine if a site meets requirements to construct a wind turbine or 
wind farm, companies erect METs. These towers are used to gather wind 
data necessary for site evaluation and development of wind energy 
projects. The data generally is gathered over a year to ascertain if 
the targeted area represents a potential location for the installation 
of wind turbines.
    Requirements to file notice under part 77 generally do not apply to 
structures at heights lower than 200 feet AGL unless close to an 
airport environment. Therefore, the FAA does not have a database of MET 
locations, nor does it conduct an aeronautical study to determine 
whether the particular structure would be hazardous to aviation. These 
towers are often installed in remote or rural areas, just under 200 
feet above ground level (AGL), usually at 198 feet or less. These 
structures are portable, erected in a matter of hours, installed with 
guyed wires and constructed from a galvanized material often making 
them difficult to see in certain atmospheric conditions.
    While the METs described above are not subject to the provisions of 
part 77 and therefore, the FAA does not conduct aeronautical studies to 
determine whether these structures are obstructions and adversely 
impact air navigation, the FAA does acknowledge that these towers under 
certain conditions may be difficult to see by low-level agricultural 
flights operating under visual flight rules. The color, portability of 
these towers, their placement in rural and remote areas, and their 
ability to be erected quickly are factors that pilots should be aware 
of when conducting operations in these areas.
    The FAA has received complaints and inquiries from agricultural 
operations in remote or rural areas regarding the safety impacts of 
these towers on low-level agricultural operations. In addition, 
representatives from the National Agricultural Aviation Association 
(NAAA) met with the FAA on November 16, 2010 to discuss safety specific 
concerns of the aerial application industry. The NAAA suggested safety 
guidelines and marking and lighting criteria in order to reduce the 
risks for aerial applications. A copy of the material provided by NAAA 
has been placed in the docket.

Proposed Guidance

    The FAA is considering revising AC No. 70/7460-1, Obstruction 
Marking and Lighting, to include guidance for the voluntary marking of 
METs that are less than 200 feet AGL. The FAA recognizes the need to 
enhance the conspicuity of these METs, particularly for low-level 
agricultural operations and seeks public comment on the guidance 
provided below.
    The FAA recommends that the towers be painted in accordance to the 
marking criteria contained in Chapter 3, paragraphs 30-33 of AC No. 70/
7460-1. In particular, we reference paragraph 33(d), which discusses 
alternate bands of aviation orange and white paint for skeletal 
framework of storage tanks and similar structures, and towers that have 
cables attached. The FAA also recommends spherical and/or flag markers 
be used in addition to aviation orange and white paint when additional 
conspicuity is necessary. Markers should be installed and displayed 
according to the existing standards contained in Chapter 3, paragraph 
34 of AC No. 70/70460-1.
    The FAA is also considering recommending high visibility sleeves on 
the outer guy wires of these METs. While the current Obstruction 
Marking and Lighting Advisory Circular does not contain such guidance 
for high visibility sleeves, the FAA specifically seeks comments on 
this recommendation.
    The FAA anticipates that a uniform and consistent scheme for 
voluntarily marking these METs would enhance safety by making these 
towers more readily identifiable for agricultural operations.

    Issued in Washington, DC, on December 29, 2010.
Edith V. Parish,
Manager, Airspace, Regulations and ATC Procedures Group.
[FR Doc. 2010-33310 Filed 1-4-11; 8:45 am]
BILLING CODE 4910-13-P


