Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 33139 

REVISIONS TO IFR ALTITUDES AND CHANGEOVER POINTS—Continued 

[Amendment 494 effective date June 30, 2011] 

From To MEA 

*3500—MRA 

§ 95.6438 VOR Federal Airway V438 

IS AMENDED TO READ IN PART.

#Grantsville, MD VOR/DME .......................................................... *Flint, MD FIX .............................................................................. 5300 

*4300—MCA Flint, MD FIX, W BND 

#Grantsville DME Unusable Beyond 20NM, Below 6000 

Flint, MD FIX ................................................................................. Hagerstown, MD VOR ................................................................. 4000 

From To MEA MAA 

§ 95.7001 Jet Routes 

§ 95.7079 Jet Route J79 

IS AMENDED TO READ IN PART.

#Key west, FL VORTAC ................................................... Dolphin, FL VORTAC ....................................................... 18000 45000 

#Key West R–037 Unusable 

§ 95.8003 VOR Federal Airway Changeover Points Airway Segment V157 

From To 

Changeover Points 

Distance From 

IS AMENDED TO ADD CHANGEOVER POINT.

Vance, SC VORTAC ......................................................... Florence, SC VORTAC .................................................... 21 Vance 

V3 

IS AMENDED TO ADD CHANGEOVER POINT.

Vance, SC VORTAC ......................................................... Florence, SC VORTAC .................................................... 21 Vance 

V438 

IS AMENDED TO ADD CHANGEOVER POINT.

Grantsville, MD VOR/DME ................................................ Hagerstown, MD VOR ..................................................... 39 Grantsville 

[FR Doc. 2011–14043 Filed 6–7–11; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 417 

[Docket No. FAA–2011–0181; Amdt. No. 

417–2] 

RIN 2120–AJ84 

Launch Safety: Lightning Criteria for 

Expendable Launch Vehicles 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Direct final rule; request for 

comments. 

SUMMARY: The FAA is amending its 

lightning commit criteria to account for 

new information about the risks of 

natural and triggered lightning. This 

action amends flight criteria for 

mitigating against naturally occurring 

lightning and lightning triggered by the 

flight of an expendable launch vehicle 

through or near an electrified 

environment in or near a cloud. These 

changes will increase launch 

availability and implement changes 

already adopted by the United States 

Air Force. 

DATES: Effective July 25, 2011. Submit 

comments on or before July 8, 2011. 

ADDRESSES: You may send comments 

identified by Docket Number FAA– 

2011–0181 using any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov and follow 

the instructions for sending your 

comments electronically. 

• Mail: Send comments to Docket 

Operations, U.S. Department of 

Transportation, 1200 New Jersey 

Avenue, SE., West Building Ground 

Floor, Room W12–140, Washington, DC 

20590. 

• Fax: Fax comments to Docket 

Operations at 202–493–2251. 

• 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. 

For more information on the 

rulemaking process, see the 

SUPPLEMENTARY INFORMATION section of 

this document. 

Privacy: We will post all comments 

we receive, without change, to http:// 

www.regulations.gov, including any 

personal information you provide. 

Using the search function of our docket 

web site, anyone can find and read the 

comments received into any of our 

dockets, including the name of the 

individual sending the comment (or 

signing the comment for an association, 

business, labor union, etc.). You may 

review DOT’s complete Privacy Act 

Statement in the Federal Register 

published on April 11, 2000 (65 FR 

19477–78) or you may visit http:// 

DocketsInfo.dot.gov. 

Docket: To read background 

documents or comments received, go to 

http://www.regulations.gov at any time 

or 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 


srobinson on DSK4SPTVN1PROD with RULES
33140 Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 

5 p.m., Monday through Friday, except 

Federal holidays. 

FOR FURTHER INFORMATION CONTACT: For 

technical questions concerning this rule 

contact Karen Shelton-Mur, Office of 

Commercial Space Transportation, 

AST–300, Federal Aviation 

Administration, 800 Independence 

Avenue, SW., Washington, DC 20591; 

telephone (202) 267–7985; facsimile 

(202) 267–5463, e-mail Karen.SheltonMur@faa.gov. 

For legal questions concerning this 

rule contact Laura Montgomery, Senior 

Attorney for Commercial Space 

Transportation, Office of the Chief 

Counsel, Federal Aviation 

Administration, 800 Independence 

Avenue, SW., Washington, DC 20591; 

telephone (202) 267–3150; facsimile 

(202) 267–7971, e-mail 

laura.montgomery@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Authority for This Rulemaking 

The FAA’s authority to issue rules on 

commercial space transportation safety 

is found in Title 49 of the United States 

Codes, section 322(a), which authorizes 

the Secretary of Transportation to carry 

out rulemakings. 51 U.S.C. subtitle V, 

chapter 509, 51 U.S.C. 50901–50923 

(Chapter 509) governs the FAA’s 

regulation of the safety of commercial 

space transportation. This rulemaking is 

promulgated under the authority of 

section 322(a). 

Direct Final Rule Procedure 

The FAA anticipates this regulation 

will not result in adverse or negative 

comment and therefore is issuing it as 

a direct final rulemaking. Because the 

changes to the lightning commit criteria 

will increase launch availability and are 

already implemented at Air Force 

launch ranges, the public interest is well 

served by this rulemaking. 

Unless a written adverse or negative 

comment or a written notice of intent to 

submit an adverse or negative comment 

is received within the comment period, 

the regulations will become effective on 

the date specified above. After the close 

of the comment period, the FAA will 

publish a document in the Federal 

Register indicating that no adverse or 

negative comments were received and 

confirming the date on which the final 

rule will become effective. If the FAA 

does receive, within the comment 

period, an adverse or negative comment, 

or written notice of intent to submit 

such a comment, the FAA will 

withdraw the direct final rule by 

publication in the Federal Register, and 

a notice of proposed rulemaking may be 

published with a new comment period. 

Comments Invited 

The FAA invites interested persons to 

participate in this rulemaking by 

submitting written comments, data, or 

views. The agency also invites 

comments relating to the economic, 

environmental, energy, or federalism 

impacts that might result from adopting 

the changes. The most helpful 

comments reference a specific portion of 

the proposal, explain the reason for any 

recommended change, and include 

supporting data. To ensure the docket 

does not contain duplicate comments, 

please send only one copy of written 

comments, or if you are filing comments 

electronically, please submit your 

comments only one time. 

The FAA will file in the docket all 

comments we receive, as well as a 

report summarizing each substantive 

public contact with FAA personnel 

concerning this rulemaking. Before 

acting on this proposal, the FAA will 

consider all comments received on or 

before the closing date for comments. 

The agency will consider comments 

filed after the comment period has 

closed if possible without incurring 

expense or delay. The FAA may make 

changes in light of the comments 

received. 

Proprietary or Confidential Business 

Information 

Do not file in the docket information 

that you consider to be proprietary or 

confidential business information. Send 

or deliver this information directly to 

the person identified in the FOR FURTHER

INFORMATION CONTACT section of this 

document. Mark the information that is 

considered proprietary or confidential. 

If the information is on a disk or CD– 

ROM, mark the outside of the disk or 

CD–ROM and also identify 

electronically within the disk or CD– 

ROM the specific information that is 

proprietary or confidential. 

Under 14 CFR 11.35(b), when the 

FAA is aware of proprietary information 

filed with a comment, the agency does 

not place it in the docket. The FAA 

holds it in a separate file to which the 

public does not have access, and the 

agency places a note in the docket that 

it has received it. If the FAA receives a 

request to examine or copy this 

information, the FAA treats it as any 

other request under the Freedom of 

Information Act, 5 U.S.C. 552. The FAA 

processes such a request under the DOT 

procedures found in 49 CFR part 7. 

Availability of Rulemaking Documents 

You can get an electronic copy using 

the Internet by: 

(1) Searching the Federal 

eRulemaking portal at http:// 

www.regulations.gov; 

(2) Visiting the FAA’s Regulations and 

Policies web page at http:// 

www.faa.gov/regulations_policies/; or 

(3) Accessing the Government 

Printing Office’s web page at http:// 

www.gpoaccess.gov/fr/index.html. 

You can also get a copy by sending a 

request to the Federal Aviation 

Administration, Office of Rulemaking, 

ARM–1, 800 Independence Avenue, 

SW., Washington, DC 20591, or by 

calling (202) 267–9680. Make sure to 

identify the docket and amendment 

numbers of this rulemaking. 

I. Background 

On August 25, 2006, the FAA issued 

requirements designed for an 

expendable launch vehicle (ELV) to 

avoid natural and triggered lightning 

during flight. Licensing and Safety 

Requirements for Launch, 71 FR 50508 

(Aug. 25, 2006). An ELV is an 

unmanned rocket that typically carries 

satellites to orbit. ELVs carry large 

amounts of fuel and, due to the 

explosive nature of the fuel, may not be 

permitted to reach populated areas in 

the event they go off course. In the 

United States, safety for ELVs is 

achieved by use of a flight termination 

system. A flight termination system 

prevents an errant launch vehicle from 

reaching a populated area by destroying 

the vehicle. A flight termination system 

consists of all components on board a 

launch vehicle that provide the ability 

to end its flight in a controlled manner. 

Without the restrictions mandated by 

appendix G of part 417, a lightning 

strike could disable a flight safety 

system yet allow continued flight of the 

launch vehicle without a launch 

operator being able to stop its flight. 

By codifying appendix G, the FAA 

implemented criteria developed by a 

Lightning Advisory Panel (LAP) to the 

National Aeronautics and Space 

Administration (NASA) and the U.S. Air 

Force. See Merceret et al., ed., A History 

of the Lightning Launch Commit Criteria 

and the Lightning Advisory Panel for 

America’s Space Program, NASA/SP– 

2010–216283, 124, par. 25 (Aug. 2010) 

(A History of the Lightning Criteria) and 

Rationales for the Lightning FlightCommit Criteria, NASA/TP–2010– 

216291, (Oct. 7, 2010)(Rationales for 

Lightning Criteria). Appendix G’s flight 

commit criteria impose time and 

distance restrictions on launch, 

requiring a launch operator to wait to 

initiate flight for specified amounts of 

time after a lightning strike or when 

launch would take a flight path too 

close to an electrified cloud. 


srobinson on DSK4SPTVN1PROD with RULES
Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 33141 

1A launch operator must follow its safety rules. 

14 CFR 417.113(a)(3). 

In this direct final rule, the FAA is 

permitting greater launch availability. In 

brief, the FAA is reducing requirements 

that a launch operator wait to launch by 

expanding the applicability of certain 

exceptions and recognizing that the risk 

of triggering lightning is less than 

previously understood at distances 

closer than previously believed. The 

FAA is also codifying criteria for 

obtaining accurate radar reflectivity 

measurements to ensure calculation of 

the volume-averaged, height-integrated 

radar reflectivity (VAHIRR) and other 

measurements, such as the vertical 

extent of a cloud top, are representative 

of actual conditions at the time of 

launch, because these calculations are 

instrumental in determining the 

presence of and risk posed by electrified 

clouds. 

II. New Requirements 

A. General Applicability 

The FAA is revising the general 

description of appendix G to clarify that 

the flight commit criteria are to mitigate 

lightning strikes and avoid initiation of 

lightning when a launch vehicle flies 

near or through a highly electrified 

environment in or near a cloud. The 

FAA is also clarifying that, when a 

launch operator uses optional 

equipment, such as a field mill, to 

increase launch availability, an operator 

may not ignore data that does not satisfy 

the requirement. This addition, 

particularly when read in conjunction 

with 14 CFR 417.113(c)(1)(ii), should 

ensure that a launch takes place only 

when it is clear that all the criteria are 

satisfied. Section 417.113(c)(1)(ii) states 

that a launch operator’s launch safety 

rules 1 must ensure there is clear and 

convincing evidence that the criteria of 

appendix G, which apply to the 

conditions present at the time of lift-off, 

are not violated. Section G417.1 states 

that all lightning flight commit criteria 

of Appendix G must be satisfied. In 

other words, each paragraph of each 

section must be individually satisfied at 

the time of launch. In short, the burden 

is on the launch operator to ensure that 

conditions are safe for launch. 

A launch operator must understand 

that each of the sections of appendix G 

deliberately prohibits launch under 

certain conditions. Since all of the 

criteria must be satisfied, appendix G 

must be read in its entirety to determine 

whether or not launch is prohibited. 

Thus, the satisfaction of any particular 

paragraph or section cannot be 

considered to permit launch. Even the 

simultaneous satisfaction of all sections 

means only that there are no known 

natural- or triggered-lightning threats 

that prohibit launch. According to 

§ 417.113(c)(1)(ii), it is still necessary for 

the launch weather team to report any 

other hazardous conditions to the 

person with authority for deciding 

whether or not to launch. 

B. New Definitions and Clarifications of 

Existing Definitions 

Section G.417.3 of appendix G defines 

terms if they would not be familiar to 

a trained meteorological observer, such 

as ‘‘field mill,’’ or if they constitute nonstandard usage of an otherwise familiar 

term, such as ‘‘associated.’’ The FAA is 

adding new definitions, clarifying 

existing ones, and making minor 

editorial changes to others. For terms 

not defined in this section, a useful 

reference is the AMS Glossary of 

Meteorology, American Meteorological 

Society, 2000: Glossary of Meteorology, 

2nd ed., American Meteorological 

Society, Boston, MA, 850; also available 

on line at http:// 

amsglossary.allenpress.com/glossary. 

New definitions to appendix G 

include definitions of Cone of silence, 

Electric field, Horizontal distance, 

Radar reflectivity, and Slant distance. 

A cone of silence is a volume within 

which a radar cannot detect any object 

and is an inverted circular cone 

centered on the radar antenna. A cone 

of silence consists of all elevation angles 

greater than the maximum elevation 

angle reached by the radar. The cone of 

silence is a volume that the radar beam 

cannot access because of a radar’s 

maximum tilt elevation. Radar echoes 

close to and directly above the radar 

cannot be detected. The methodology of 

section G417.25(b) provides that the 

specified volume for the VAHIRR 

calculation must not contain any 

portion of the cone of silence. Note as 

well that, for any given search pattern, 

certain sectors may be blocked out for 

reasons of payload safety, and the 

specified volume also may not contain 

any portion of a sector blocked out for 

these reasons. The methodology of 

section G417.25(a) also provides that no 

other radar reflectivity measurements, 

such as those used to delineate a cloud, 

may be affected by any volume that is 

inaccessible to the radar. 

An electric field is a vertical electric 

field (Ez) at the surface of the Earth. 

This definition differentiates the surface 

electric field from those measured aloft. 

A horizontal distance is a distance 

that is measured horizontally between a 

field mill or electric-field-measurement 

point and the nearest part of the vertical 

projection of an object or flight path 

onto the surface of the Earth. The FAA 

is defining horizontal distance in order 

to distinguish between the measurement 

of this two-dimensional distance and 

the three-dimensional ‘‘slant distance.’’ 

Radar reflectivity means the radar 

reflectivity factor due to hydrometeors, 

in dBZ. This is non-standard usage of a 

term that is defined in the Glossary of 

Meteorology. Radar reflectivity 

measurements in units of dBZ (as 

defined in the Glossary and not further 

discussed herein) are further specified 

in section G417.25(a) and are used 

throughout this appendix, including for 

the calculation of VAHIRR. 

A slant distance means the shortest 

distance between two points, whether 

horizontal, vertical, or inclined in three 

dimensional space. A slant distance is 

used in measuring the distance between 

a radar reflectivity or VAHIRR 

measurement point and either a flight 

path or an object such as a cloud. 

The FAA is also clarifying the 

definitions of Associated, Cloud, 

Disturbed weather, Flight path, 

Transparent, and Volume-averaged 

height-integrated radar reflectivity 

(VAHIRR). The following paragraphs 

describe the changes made to these 

definitions and the reasons for those 

changes. 

Associated means two or more clouds 

are caused by the same disturbed 

weather or are physically connected. 

The FAA is deleting the discussion 

contained in the current definition. 

Discussion is better placed in 

explanatory material like this preamble, 

and is unnecessary in regulatory text. 

Accordingly, it is still the case that 

‘‘associated’’ does not have to mean 

occurring at the same time. It is also still 

the case that a cumulus cloud formed 

locally and a cirrus layer physically 

separated from that cumulus cloud and 

generated by a distant source are not 

associated, even if they occur over or 

near the launch point at the same time. 

A cloud is a visible mass of 

suspended water droplets, ice crystals, 

or a combination of water droplets and 

ice crystals. A ‘‘cloud’’ includes the 

entire volume containing such particles. 

This clarification omits an unnecessary 

reference to the particles being 

produced by condensation of water 

vapor in the atmosphere. Note that this 

definition works together with that of 

‘‘slant distance’’ to specify that standoff 

distances from a cloud be measured 

from the nearest edge of that cloud. 

Disturbed weather is a weather system 

where a dynamical process destabilizes 

the air on a scale larger than individual 

clouds or cells. Disturbed weather 

specifically includes, but is not limited 

to, fronts, troughs, and squall lines. (In 


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33142 Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 

this case, the examples are retained as 

a critical part of the definition.) The 

body of the definition remains 

unchanged, but the FAA is now adding 

a squall line as an important example of 

disturbed weather because, along with 

fronts and troughs, it is frequently 

related to electrification of the 

associated clouds. 

Flight path means a launch vehicle’s 

planned flight trajectory, including the 

trajectory’s vertical and horizontal 

uncertainties resulting from all threesigma guidance and performance 

deviations. The FAA is no longer 

referencing wind effects because threesigma dispersions already take wind 

effects into account. 

The definition of transparent is 

clarified to mean any of the following 

conditions apply: 

➣ Objects above, including higher 

clouds, blue sky, and stars are not 

blurred, are distinct, and are not 

obscured when viewed at visible 

wavelengths; 

➣ Objects below, including terrain, 

buildings, and lights on the ground, are 

clear, distinct, and not obscured when 

viewed at visible wavelengths; 

➣ Objects above or below are seen 

distinctly not only through breaks in a 

cloud; 

➣ The cloud has a radar reflectivity 

of less than 0 dBZ. 

Historically, transparency has been 

determined by a person watching the 

sky. The weather experts at the Federal 

launch ranges prefer observations 

undertaken by a person. Rather than 

limiting visual observations to those 

made by a person standing outdoors, 

this definition reflects the fact that 

transparency may be determined by 

satellite or camera as well. A person 

may also look at images of the 

conditions outside to ascertain 

transparency. For these reasons, the 

phrase ‘‘at visible wavelengths’’ has been 

retained; clouds that look transparent to 

a human observer may not look 

transparent to an imaging sensor 

operating at another wavelength, and 

vice versa. 

Volume-averaged height-integrated 

radar reflectivity means the product, 

expressed in units of dBZ-km, of the 

volume-averaged radar reflectivity (in 

dBZ) and the average cloud thickness 

(in kilometers) in the specified volume 

determined by a VAHIRR-measurement 

point. The old definition states that the 

calculation applies to ‘‘a specified 

volume relative to a point along the 

flight track.’’ The change clarifies that 

VAHIRR may be computed at points 

other than along a flight path. New 

section G417.25(b) describes in detail 

how VAHIRR is calculated. 

Additionally, the FAA is making 

minor editorial changes to the following 

definitions: Anvil cloud, Precipitation, 

Moderate precipitation, Thick cloud 

layer, Triboelectrification, and Volumeaveraged height-integrated radar 

reflectivity. 

The FAA is also deleting several 

definitions. 

Cloud edge is being deleted because it 

is now part of the definition of a cloud. 

Electric field measurement at the 

surface of the Earth is being deleted. 

The criteria this term contained are 

more accurately characterized as 

requirements, and, therefore, now 

appear in new section G417.25(c) 

Electric field measurement, which 

governs how to measure electric fields. 

Electric field measurement aloft is 

removed because Appendix G contains 

no criteria for electric field 

measurement aloft in the regulations. 

Although the FAA initially considered 

criteria for electric fields aloft, in the 

end, it did not promulgate requirements 

when it issued part 417. The definition 

was inadvertently left in the final rule. 

The definition of Ohms/square is 

removed because the term is a standard 

unit of measurement. The definition of 

Specified volume is no longer necessary 

because the term contained 

requirements now located in section 

G417.25. Treated is being deleted 

because it contained requirements now 

located in section G417.23(b). Within is 

being deleted because more precise 

language regarding the distance between 

a flight path and a cloud should prevent 

any misunderstanding regarding the 

distance for which a launch operator 

must account. 

III. Changes to Temperature, Time, and 

Distance Restrictions for Anvil and 

Debris Clouds 

In this direct final rule, the FAA is 

permitting greater launch availability. In 

brief, the FAA is reducing requirements 

that a launch operator wait to launch by 

expanding the applicability of certain 

exceptions and decreasing waiting time 

requirements because of recognition that 

the risk of triggering lightning is less 

than previously understood at distances 

closer than previously believed. In order 

to ensure satisfaction of minimum 

standards of measurement and 

uniformity across launch sites, the FAA 

is codifying in new section G417.25 the 

measurement criteria used during a 

second airborne field mill campaign 

(ABFM–II) conducted during 2000 and 

2001. A lightning advisory panel that 

provides expertise to the Air Force and 

NASA recommended this approach to 

the ranges. The FAA also accepts the 

more simple approach that the ranges 

currently use to calculate volumeaveraged, height-integrated radar 

reflectivity because it is more 

conservative than the codified 

approach. Acceptable techniques to 

calculate VAHIRR are further discussed 

in Section III.C.3 below. 

A. Structural Changes 

At the outset, the FAA must note that 

the order of the new requirements for 

anvil and debris clouds is reversed from 

the old requirements. These new rules 

have also been written so that only one 

set of restrictions applies at a time. For 

example, for attached anvil clouds, in 

old section G417.9. 

• Paragraph (a) contains requirements 

for flight paths through or within 10 

nautical miles of the cloud, 

• Paragraph (b) contains requirements 

for flight paths through or within 5 

nautical miles of the cloud, and 

• Paragraph (c) contains requirements 

for flight paths through a cloud. 

This organization is potentially 

confusing, since all three paragraphs 

apply to flight through, and both 

paragraphs (a) and (b) apply to flight 

within 5 nautical miles of, the cloud. 

The application has been simplified in 

the new G417.9, where— 

• Paragraph (b) contains all 

requirements for flight paths through a 

cloud, 

• Paragraph (c) contains all 

requirements for flight paths greater 

than 0 and less than or equal to 3 

nautical miles from the cloud, 

• Paragraph (d) contains all 

requirements for flight paths greater 

than 3 and less than or equal to 5 

nautical miles from the cloud, and 

finally, 

• Paragraph (e) contains all 

requirements for flight paths greater 

than 5 and less than or equal to 10 

nautical miles from a cloud. 

Whereas more than one paragraph 

could apply under the old rule, the end 

result of this restructuring is that, for 

any given slant distance from a cloud, 

at most, one paragraph will apply in the 

new rule. For example, suppose a 

launch vehicle’s flight path would place 

the closest approach of the vehicle 2 

nautical miles from an attached anvil 

cloud. Under the old rule, the operator 

would need to satisfy the requirements 

of both sections G417.9(a), because 2 

nautical miles is less than 10 nautical 

miles, and G417.9(b), because 2 nautical 

miles is less than 5 nautical miles. 

Under the new rule, the operator only 

needs to satisfy the requirements of 

G417.9(c) because 2 nautical miles is 

between zero and 3 nautical miles. This 

change should make the rules easier to 

follow. However, because of this 


srobinson on DSK4SPTVN1PROD with RULES
Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 33143 

2Willett, ed., Rationales for Lightning Criteria, at 

9, 45, 61, and 108. 

3 Id. at 45. 

4 Dye, J.E., W.P. Winn, J.J. Jones, and D.W. Breed, 

1989: The electrification of New Mexico 

Thunderstorms. 1. Relationship between 

precipitation development and the onset of 

electrification, J. Geophys. Res., 94, 8643–8656. 

Breed, D.W., and J.E. Dye, 1989: The electrification 

of New Mexico Thunderstorms Part 2. Electric field 

growth during initial electrification. J. Geophys. 

Res, 94, 14, 841–14, 854. 

restructuring, there is not a one-to-one 

correspondence between the paragraphs 

of the old and new rules. 

Even in the rules that have been 

structurally rearranged, it must be 

remembered that slant distance from a 

cloud refers only to the closest approach 

of the vehicle. Otherwise multiple 

paragraphs may still be taken to apply. 

An operator must always take care that 

all paragraphs are satisfied. 

B. Clarification of Applicability of 

Restrictions to Anvil Clouds Formed 

From Parents at Altitudes below ¥10 

Degrees Celsius 

Under new paragraphs (a) of sections 

G417.9 and G417.11, for both attached 

and detached anvil clouds, the 

requirements to wait before initiating 

flight apply only when an anvil cloud 

forms from a parent cloud that has a top 

at an altitude where the temperature is 

¥10 degrees Celsius or colder. Even 

though anvil clouds can form in 

temperatures slightly above freezing, 

only anvil clouds with parents whose 

tops are at altitudes with temperatures 

at or below ¥10 degrees Celsius pose a 

real possibility of containing high 

electric fields.2 When a convective 

cloud grows through different altitudes, 

it may reach altitudes with freezing or 

colder temperatures. At these altitudes 

the cloud may acquire ice particles, ice 

crystals, super-cooled water droplets or 

a combination thereof. It is primarily 

this mixture of phases that can produce 

a strong electrical generator within the 

cloud. When the cloud top has become 

colder than ¥10 degrees Celsius, the 

cloud is likely to be electrified, and 

when its top has become colder than 

¥20 degrees Celsius, strong 

electrification is likely.3

The temperature criterion in 

paragraphs (a) applies to the parent 

cloud. Anvil clouds are limited to 

outflow from convective clouds at 

altitudes with temperatures at or colder 

than ¥-10 degrees Celsius. According to 

studies, anvil clouds that develop from 

cumulus clouds with cloud top 

temperatures warmer than ¥10 degrees 

Celsius rarely develop electric fields 

with the strength of a thunderstorm.4

In practice, this limitation of the flight 

commit criteria to anvil clouds formed 

from parents at sufficiently cold 

altitudes is not new. Although not 

clearly expressed in the old appendix G, 

the Federal ranges have historically 

limited their restrictions on flight to 

non-transparent anvil clouds formed 

from parents at altitudes where the 

temperatures are ¥10 degrees Celsius or 

colder. 

C. Exceptions to the Requirement To 

Wait To Initiate Flight 

This rulemaking increases the 

availability of exceptions to certain 

prohibitions on initiating flight under 

circumstances posing a risk of natural or 

triggered lightning. Specifically, 

although an FAA licensee must wait 

specified amounts of time after the last 

lightning discharge to initiate flight 

through a non-transparent attached or 

detached anvil cloud or a nontransparent debris cloud, the licensee 

need not wait, under the new versions 

of the anvil and debris-cloud rules, if all 

of the non-transparent anvil or debris 

clouds within 3 nautical miles of a flight 

path are located at altitudes where the 

temperature is colder than 0 degrees 

Celsius and if the volume-averaged, 

height-integrated radar reflectivity 

(VAHIRR) is less than +10 dBZ-km. For 

the longer standoff distances, anvil 

clouds must be cold within 10 nautical 

miles, but there is no requirement to 

calculate VAHIRR. 

The launch operator must always 

remember, however, that all sections of 

Appendix G must be satisfied 

simultaneously. In particular, section 

G417.5, requires standoff distances of 10 

nautical miles from a parent 

thunderstorm and from the lightning 

itself, so there will usually be portions 

of a non-transparent anvil or debris 

cloud through which flight is prohibited 

by the lightning provision even though 

it may not be prohibited by the anvil or 

debris cloud requirements themselves. 

1. Reduced Restrictions on Launches 

With a Flight Path Greater Than 3 

Nautical Miles From an Anvil or Debris 

Cloud 

The first change reduces some 

restrictions on launches with a flight 

path greater than 3 nautical miles from 

a non-transparent anvil or debris cloud. 

For flight paths more than 3 nautical 

miles from a non-transparent anvil 

cloud, rather than requiring that a 

launch operator always wait after a 

lightning discharge, the FAA now 

requires only that the altitude of the 

portion of the cloud within a specified 

distance of the flight path be at 

temperatures less than 0 degrees Celsius 

to permit flight. For non-transparent 

debris clouds with flight paths greater 

than 3 nautical miles from the cloud, 

the FAA will no longer require any 

waiting after a lightning discharge or 

detachment. 

For non-transparent anvil clouds, the 

requirements for a waiting period for 

flight paths more than 3 nautical miles 

from a cloud are not being dropped 

entirely. However, the requirements for 

anvil clouds will be more flexible 

beyond 3 nautical miles than they are 

under the current rules. For anvil clouds 

more than 3 nautical miles from a flight 

path, the FAA will require, unless the 

operator waits 3 hours after the last 

lightning discharge, that the altitudes at 

which the flight path passes within a 

specified distance of the cloud have 

temperatures of less than 0 degrees 

Celsius. This restriction was based on 

the first Airborne Field Mill campaign 

(ABFM–II) which showed that clouds at 

altitudes with temperatures of less than 

0 degrees Celsius do not contain electric 

field magnitudes of greater than 

3 kV/m. Merceret et al., supra, 242. The 

specific rule changes for attached and 

detached anvil clouds are explained in 

turn below. The reasons for the changes 

follow these descriptions. 

i. Attached Anvil Clouds (G417.9) 

A launch operator using flight paths 

of greater than 3 and less than or equal 

to 5 nautical miles from an attached 

non-transparent anvil cloud will no 

longer always need to wait 30 minutes 

after a lightning discharge, and will no 

longer need to show that the VAHIRR is 

less than 33 dBZ-kft within 3 hours of 

a lightning discharge. The old 

requirement is contained in both section 

G417.9(a), which requires waiting for 30 

minutes after a lightning discharge 

regardless of distance, and in section 

G417.9(b), which only allows passage 

between 30 minutes and 3 hours after a 

lightning discharge, if the VAHIRR 

measurement is under +33 dBZ-kft and 

the altitudes at which the flight path 

passes within 5 nautical miles of the 

cloud have temperatures of less than 0 

degrees Celsius. 

Under the new requirements, the 

restriction applicable to flight paths 

between 3 and 5 nautical miles will be 

contained in section G417.9(d) and will 

require waiting for 3 hours after a 

lighting discharge unless, as with the 

old rule, the portion of the attached 

anvil cloud at a slant distance of less 

than or equal to 5 nautical miles from 

the flight path is located entirely at 

altitudes where the temperature is 

colder than 0 degrees Celsius. A launch 

operator will no longer be required to 

wait for 30 minutes after a lightning 

discharge and will not need to calculate 

VAHIRR to be able to launch within 3 


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33144 Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 

5For the sake of brevity, the references to ‘‘cold’’ 

anvil clouds in this discussion refer to those whose 

parent clouds have tops at an altitude where the 

temperature is equal to or colder than ¥10 degrees 

Celsius. 

hours of a lightning discharge. However, 

a launch operator will still need to show 

satisfaction of the temperature at 

altitude restriction in order to launch 

within 3 hours of a lightning discharge. 

Launch operators with flight paths of 

greater than 5 and less than or equal to 

10 nautical miles from an attached nontransparent anvil cloud will no longer 

always need to wait 30 minutes after a 

lightning discharge as required by old 

section G417.9(a). Section G417.9(e) 

will now require waiting 30 minutes 

unless the portion of the attached anvil 

cloud at a slant distance of less than or 

equal to 10 nautical miles from the 

flight path is located entirely at altitudes 

where the temperature is colder than 0 

degrees Celsius. 

ii. Detached Anvil Clouds (G417.11) 

Launch operators with flight paths 

between 3 and 10 nautical miles from a 

detached non-transparent anvil cloud 

will no longer always need to wait 30 

minutes after a lightning discharge and 

will no longer need to meet any 

requirements once 30 minutes have 

passed since the last lightning 

discharge. The new G417.11(d) will 

require that the launch operator wait 30 

minutes after a lightning discharge from 

the cloud unless the portion of the 

detached anvil cloud at a slant distance 

of less than or equal to 10 nautical miles 

from the flight path is located entirely 

at altitudes where the temperature is 

colder than 0 degrees Celsius. Section 

G417.11(a) currently requires that a 

launch operator wait 30 minutes after a 

lightning discharge, without the benefit 

of any exceptions. Additionally, current 

G417.11(b) does not allow a launch 

operator to pass between 3 and 5 

nautical miles from a cloud between 30 

minutes and 3 hours after a lightning 

discharge unless one of two sets of 

conditions are met. The new 

requirements are more flexible because 

they allow an exception to the 

requirement that the launch operator 

wait 30 minutes after a lightning 

discharge and because they do not 

require any conditions to be met after 30 

minutes, even between 3 and 5 nautical 

miles. 

iii. Rationale 

The reduced restrictions on a flight 

path in excess of 3 nautical miles of a 

cold 5 anvil or debris cloud arise out of 

experimental and statistical work 

performed by the LAP, which 

recommends lightning requirements for 

launches at Federal launch ranges. The 

LAP has performed statistical analyses 

of data collected during ABFM–II. The 

goal of ABFM–II was to characterize the 

electric fields of anvil and debris clouds 

by flying an aircraft into these types of 

clouds while taking measurements at 

various distances from the clouds using 

electric field mills. The ABFM II 

campaign used aircraft carrying airborne 

field mills to measure the electric fields 

of clouds of interest. The campaign used 

ground-based radar to measure the 

reflectivity of the same clouds so that it 

would be possible to correlate the radar 

reflectivity of the clouds with the 

electric field measurements of the 

airborne field mills. Francis J. Merceret, 

et al., On the Magnitude of the Electric 

Field near Thunderstorm-Associated 

Clouds, 47 Journal of Applied 

Meteorology and Climatology 240, 243 

(2008). These data were used to develop 

the VAHIRR parameter associated with 

cloud electrification. Both the 

temperature and VAHIRR criteria are 

correlated with mixed-phase 

precipitation, namely, the presence of 

water in both solid and liquid phases. 

When a cloud spans the freezing 

level, the cloud can acquire a charge 

due to processes involving the mixing of 

liquid water droplets and ice crystals. A 

build up of electric charge in a cloud 

can lead to natural or triggered 

lightning. When the VAHIRR is less 

than 10 dBZ-km, it means that any 

mixed phase processes are unable to 

produce significant charging. 

Like the Air Force and NASA before 

it, the FAA’s existing triggered lightning 

criteria are based on the determination 

that a launch vehicle will not trigger 

lightning in an electric field with a 

magnitude of less than 3 kilovolts per 

meter (kV/m). The following discussion 

of each of the changes to the FAA’s 

lightning commit criteria will, therefore, 

focus on showing how the FAA’s new 

requirements ensure that the electric 

field magnitude along the flight path 

will be less than 3 kV/m, so that the 

new requirements will be essentially as 

safe as the current requirements. 

Therefore, the FAA is able to follow 

the Federal launch range’s lead in 

making the rules less restrictive because 

of new analyses of the ABFM–II data. 

T.P. O’Brien & R. Walterscheid, 

Supplemental Statistical Analysis of 

ABFM–II Data for Lightning Launch 

Commit Criteria, Aerospace Report No. 

TOR–2007(1494)–6, 3 (2007). 

As a purely qualitative matter, out of 

158 flights through non-transparent 

debris or anvil clouds during ABFM–II, 

the field mills detected no electric field 

with a magnitude of greater than 3 kV/ 

m outside of a cloud. This was so even 

though the sample contained 30 flights 

through clouds with an electric field 

magnitude of more than 3 kV/m 

somewhere inside the cloud. Id. 

Based on the data obtained, a 

qualitative analysis shows that flying 

more than 3 nautical miles from a nontransparent anvil cloud is as safe as the 

FAA’s current requirements. The LAP 

also used this data to demonstrate 

statistically in two ways that it is 

extremely unlikely that the electric field 

magnitude will be more than 3 kV/m at 

distances greater than 3 nautical miles 

from the clouds. 

A launch operator may calculate 

VAHIRR to help determine whether it is 

safe to fly, even if there has been a 

relatively recent lightning discharge. If 

the VAHIRR is less than 10 dBZ-km 

(about 33 dBZ-kft), the probability of an 

electric field of greater than 3 kV/m 

occurring is less than 1 in 10,000. Dye 

et al., supra, 14. 

Calculating VAHIRR consists of 

multiplying the average cloud thickness 

and the average radar reflectivity found 

in a column with an 11 kilometer by 11 

kilometer cross-section centered on a 

point of interest, where the two sides 

are oriented north-south and east-west. 

Because 3 nautical miles is 5.52 

kilometers, a VAHIRR box centered on 

a flight path more than 3 nautical miles 

from the anvil cloud’s edge will not 

contain the anvil cloud and will, 

therefore, have a radar reflectivity of 

zero, meaning that the VAHIRR will be 

zero. Because zero is clearly less than 

+33 dBZ-kft, flight at more than 3 

nautical miles from the cloud will be at 

least as safe as the current requirements 

of G417.9(b)(2) and G417.11(b)(2)(ii), 

which only require a VAHIRR of less 

than +33 dBZ-kft. James E. Dye, et al., 

Analysis of Proposed 2007–2008 

Revisions to the Lightning Launch 

Commit Criteria for United States Space 

Launches, 13th Conference on Aviation, 

Range and Aerospace Meteorology 8.2, 

2–3 (available at http://ams.confex.com/ 

ams/88Annual/techprogram/ 

programexpanded_474.htm) (2008); 

Francis J. Merceret, Risk Analysis of 

Proposed Reduction of Anvil and Debris 

Cloud LLCC Standoff Distances from 

Five to Three Miles, 1–2 (2007) (internal 

LAP memorandum). 

The LAP also performed a Gaussian 

statistical analysis on the electric field 

data collected between 6 kilometers (3.2 

nautical miles) and 12 kilometers (6.5 

nautical miles) from anvil and debris 

clouds in an attempt to determine the 

likelihood of various electric field 

magnitudes occurring at those distances 

from the clouds. The LAP found that an 

electric field of significance was highly 

unlikely. 


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Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 33145 

The LAP used a Gaussian distribution 

to perform a conservative three-sigma 

worst-case risk analysis by using an 

assumed mean of three times the 

measured mean and an assumed error 

estimate of three times the calculated 

error. The LAP concluded that, even 

with these conservative assumptions, 

the probability that an electric field with 

a magnitude of 3 kV/m would occur 

within 3.2 to 6.5 nautical miles of a nontransparent anvil or debris cloud was 

negligible; the probability of a field of 

even 2 kV/m was on the order of 10¥7. 

Dye et al., supra, at 3–4. These 

probabilities were obtained by only 

analyzing non-transparent clouds that 

typically contain elevated electric fields, 

namely, those that somewhere 

contained electric fields greater than 3 

kV/m. Merceret, supra, at 2–6. The FAA 

concludes from this analysis that 

launches more than 3 nautical miles 

from anvil and debris clouds are 

unlikely to trigger lightning because it is 

extremely remote for the electric field to 

reach a magnitude of 3 kV/m at 

distances more than 3 nautical miles 

from these clouds. 

However, this analysis uses an 

unconventional technique for extreme 

value analysis. Gaussian analysis is not 

typically used to determine the 

likelihood of a quantity that is relatively 

far from any of the observed quantities. 

Therefore, the LAP also performed a 

second statistical analysis. Dye et al., 

supra, at 4–5. 

The LAP used a second statistical 

method to determine the probability of 

the electric field magnitude exceeding 3 

kV/m at various distances from the anvil 

and debris clouds in increments of 0.6 

kilometers (0.32 nautical miles) and 

again found it extremely unlikely. 

O’Brien & Walterscheid, supra, at 7. 

Gaussian distributions are not 

necessarily well suited to extrapolating 

fits to the wings of a frequency 

distribution where the event frequency 

(in this case the frequency of fields 

exceeding 3 kV/m) is very small. A 

widely used function for extreme value 

estimation is the Weibull function. For 

each distance increment from the 

clouds, a 2-parameter Weibull 

distribution was a good statistical fit for 

the data. Extrapolating the tail of the 

Weibull shows how likely it would be 

at each increment to encounter an 

electric field with a magnitude greater 

than 3 kV/m. Even at 0.6 kilometers 

(0.32 nautical miles) from the cloud’s 

edge, the probability of exceeding 3 kV/ 

m was on the order of 10¥9. If only 

clouds containing an electric field of 

over 3 kV/m were considered, the 

calculated probability was somewhat 

lower, but this is most likely a statistical 

artifact relating to sample size. At 5.4 

kilometers (2.9 nautical miles), the 

probability was under 10¥16 even if 

only clouds containing an electric field 

of over 3 kV/m were considered. 

O’Brien & Walterscheid, supra, at 7. 

Therefore, the FAA concludes that the 

risk of encountering electric field 

magnitudes greater than 3 kV/m is very 

small if the flight path is more than 3 

nautical miles from the edge of an anvil 

or debris cloud. In fact, the Weibull fit 

analysis indicates that a launch would 

not likely encounter a field of 3 kV/m 

even if the flight path was at 0.32 

nautical miles from the cloud’s edge, so 

the requirements to wait or satisfy the 

VAHIRR criteria on launches with flight 

paths more than 3 nautical miles from 

a cloud’s edge are not necessary. 

iv. Reduced Restrictions on Launches 

With a Flight Path Within 3 Nautical 

Miles of a Debris Cloud 

Analysis of the ABFM–II data has also 

demonstrated that satisfying the 

VAHIRR criteria can allow greater 

launch opportunities near a nontransparent debris cloud that has 

discharged lightning. This change 

expands launch availability because at 

any distance from a cloud the 

regulations permit flight if the 

conditions satisfy the VAHIRR and 

temperature restrictions. For a flight 

path through a non-transparent debris 

cloud under old section G417.13(a), a 

launch operator must wait 3 hours after 

detachment or a lightning discharge 

without exception. New section 

G417.13(a) requires a launch operator to 

wait 3 hours only if the operator cannot 

demonstrate that the VAHIRR is below 

10 dBZ-km (+33 dBZ-kft) and that every 

portion of the non-transparent debris 

cloud at a slant distance within 5 

nautical miles of the flight path is at 

altitudes where the cloud has 

temperatures of less than 0 degrees 

Celsius. 

For flight paths between 0 and 3 

nautical miles from the debris cloud, the 

current section G417.13(b) requires 

waiting 3 hours unless the launch meets 

three conditions: 

1. There is at least one working field 

mill within 5 nautical miles of the 

cloud, 

2. The magnitude of the electric field 

measurements has been less than 1 kV/ 

m for 15 minutes within 5 nautical 

miles of the cloud, and 

3. The maximum radar reflectivity has 

been less than 10 dBZ for 15 minutes 

within 5 nautical miles of the cloud. 

The new requirements still allow the 

fulfillment of these three conditions as 

a method to avoid waiting the 3-hour 

period, but will also allow earlier flight 

if the operator meets the VAHIRR 

exception, and if every portion of the 

debris cloud at a slant distance within 

5 nautical miles of the flight path is at 

altitudes where the cloud has 

temperatures of less than 0 degrees 

Celsius. 

A VAHIRR measurement of less than 

10 dBZ-km (or approximately 33 dBZkft), along with satisfactory field mill 

measurements and temperatures, means 

that a debris cloud does not contain an 

elevated electric field, even if portions 

of it are located at an altitude conducive 

to the creation of an electric charge. In 

fact, the VAHIRR method may be even 

more reliable when applied to nontransparent debris clouds than to anvil 

clouds. To demonstrate this, the LAP 

used a Weibull distribution to show that 

the upper bound of the 95-percentconfidence-interval for the probability 

of the electric field exceeding 3 kV/m if 

the VAHIRR measurement is between 5 

and 15 dBZ-km is on the order of 10¥5

for debris clouds, as opposed to 10¥2 for 

anvil clouds. The expected value of the 

probability of exceeding 3 kV/m is 

much less. A more detailed examination 

demonstrated that the expected value of 

the probability of exceeding 3 kV/m for 

anvil clouds is 10¥4 if the VAHIRR is 

less than 10 dBZ-km, so the probability 

of exceeding 3 kV/m for debris clouds 

is probably even lower than 10¥5 if the 

VAHIRR is less than 10 dBZ-km. Dye et 

al., supra, 4–5. Therefore, the FAA has 

concluded that it is appropriate to 

extend the availability of the VAHIRR 

exception to waiting to launch to debris 

clouds. 

2. Changes for Launches With a Flight 

Path Within Three Nautical Miles of an 

Attached Anvil Cloud 

For flight paths within 3 nautical 

miles of a cold, non-transparent anvil 

cloud, the FAA will now permit flight 

within 30 minutes of a lightning 

discharge when temperature and 

VAHIRR readings satisfy the regulatory 

criteria. Therefore, for flight paths 

between 0 and 3 nautical miles from a 

cloud, the new section G417.9(c) allows 

launch at any time if the VAHIRR is 

below 10 dBZ-km and every portion of 

the anvil cloud at a slant distance 

within 5 nautical miles of the flight path 

is at altitudes where the non-transparent 

cloud has temperatures of less than 0 

degrees Celsius. The old rule requires 

waiting for 30 minutes after lightning 

discharge if not passing through the 

non-transparent cloud (current 

G417.9(a) and (b)) or 3 hours after 

lightning discharge if passing through 

the non-transparent cloud (current 

G417.9(c)) unless VAHIRR and 

temperature at altitude conditions are 


srobinson on DSK4SPTVN1PROD with RULES
33146 Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 

6 Dye, J. E., et al. (2007), Electric fields, cloud 

microphysics, and reflectivity in anvils of Florida 

thunderstorms. J. Geophys. Res., 112, D11215, 

doi:10.1029/2006JD007550. 

7Rationales for Lightning Criteria, at 123. 

8NEXRAD is a network of 159 high-resolution 

Doppler weather radars operated by the National 

Weather Service, an agency of the National Oceanic 

and Atmospheric Administration (NOAA) within 

the United States Department of Commerce. 

9The Federal launch ranges employ 

meteorological radars because other radars do not 

provide sufficient granularity in depicting 

reflectivity on a gridded representation. 

10The radar used at the Eastern and Western 

Ranges is WSR–88D and WSR–74C. They meet this 

criterion. 

11 45th Weather Squadron, Steps for Evaluating 

VAHIRR, par. 6 (March 2005. 

12Blakeslee, R.J., H.J. Christian, and B. Vonnegut 

(1989), Electrical measurements over 

thunderstorms, J. Geophys. Res., 94, 135–140. 

13 45th Weather Squadron, Steps for Evaluating 

VAHIRR, Par. 2, (March 2005). 

14A History of the Lightning Criteria, 124, par. 25. 

met. The new requirements will allow 

VAHIRR and the temperature at altitude 

conditions to always be an alternative to 

having to wait after a lightning 

discharge. For detached non-transparent 

anvil clouds, the requirements remain 

the same for flight paths less than or 

equal to 3 nautical miles except that 

now a launch operator can pass within 

3 nautical miles of the non-transparent 

cloud within 30 minutes of a lightning 

discharge if the VAHIRR is below 10 

dBZ-km and every portion of the nontransparent cloud at a slant distance 

within 5 nautical miles of the flight path 

is at altitudes where the cloud has 

temperatures of less than 0 degrees 

Celsius. This change is contained in 

G417.11(c)(1). This change is possible 

because the studies of the ABFM–II 

campaign show, as discussed above, 

that electric fields greater than 3 kv/m 

do not extend as far and the decay rate 

is much more rapid near the anvil edge 6

than previously believed. Cloud charges 

decay in time in the absence of active 

charge generation and, real-time radar 

reflectivity readings and calculations 

may be used to confirm that the electric 

field has, in fact, subsided to acceptable 

levels. 

The FAA will not require a launch 

operator to wait 30 minutes when 

temperature and VAHIRR readings 

satisfy the criteria for attached and 

detached non-transparent anvil clouds 

when the flight path is between 0 and 

3 nautical miles. As described above, 

statistical analysis of the ABFM II 

measurements for all anvils shows that, 

even for highly electrified anvils with 

electric fields much greater than 3 kV/ 

m inside the cloud, the electric field 

outside of the anvil cloud falls off very 

rapidly and once falling to low levels 

remains small at greater distances. 

O’Brien. et. al. at 9. For attached and 

detached non-transparent anvil clouds 

and debris clouds, when the electric 

field is strong, namely, when it exceeds 

3 kV/m, the radar reflectivity in the 

same location over the ABFM II data set 

is invariably greater than approximately 

10 dBZ. As noted, the Weibull 

distribution and extreme value analysis 

for anvil and debris clouds showed that, 

when VAHIRR is ≤ 10 dBZ-km, the 

probability of having electric fields in 

excess of 3 Kv/m is very small (on the 

order of 10¥4 or lower). Based on these 

results, the FAA finds that a launch that 

meets the VAHIRR criterion obviates 

concerns regarding electric fields in 

excess of 3 kV/m. Strong electric fields 

are known to occur in the melting zone 

of many precipitating layer clouds.7

Satisfaction of the temperature 

requirement ensures that this type of 

electric charging within the melting 

zone will not occur. 

3. Codification of Measurement Criteria 

New section G417.25 represents a 

codification of three different sets of 

measurement specifications. Section 

G417.25(a) contains requirements for 

accurate and reliable radar reflectivity 

measurements that qualify for use 

throughout the other sections of this 

appendix. In addition to VAHIRR 

calculations, such uses include all radar 

measurements of the location, spatial 

extent, and intensity of clouds and 

precipitation. Such specifications are 

currently applied by the U.S. Air Force 

and NASA at the Federal ranges and can 

also be met by correct application of 

data from the national Next-Generation 

Radar (NEXRAD) network.8 If the 

available radar does not meet these 

requirements, a launch operator must 

fall back on visual and other 

observations to convincingly 

demonstrate that the rules are not 

violated. 

Section G417.25(b) applies 

specifically to VAHIRR calculations and 

explains how valid VAHIRR 

measurements must be made. These 

specifications are the same as those 

used during the ABFM II of 2000 and 

2001 from which a safe VAHIRR 

threshold of ≤10 dBZ-km was 

statistically determined for anvil and 

debris clouds. Because there is no 

guarantee that this threshold would be 

safe if VAHIRR were calculated 

operationally in a different way, the 

FAA is codifying these specifications 

here. See below, however, for an 

alternative calculation that is currently 

in use by the U.S. Air Force and NASA 

at the Eastern Range and that satisfies 

section G417.1(c) by being at least as 

safe as the FAA’s requirements. 

Finally, section G417.25(c) specifies 

the measurement techniques for electric 

fields to qualify for use in this 

appendix. Again, these are the 

specifications currently used by the 

federal launch ranges. 

Section G417.25(a) requires that a 

licensee who relies on radar reflectivity 

measurements, including the 

calculation of VAHIRR, to increase 

launch availability must satisfy a 

number of requirements. The Federal 

launch ranges satisfy the requirements 

of paragraph (a) of this section because 

they employ meteorological radar,9 and 

they ensure that— 

(1) The radar wavelength is greater 

than or equal to 5 centimeters in order 

that attenuation by intervening clouds 

and/or precipitation not be 

significant; 10

(2) Any reflectivity measurement is of 

a meteorological target, such as a cloud 

or precipitation, and not of some other 

objects, such as birds or insects, nor due 

to ‘‘anomalous propagation’’; 11

(3) The spatial accuracy and 

resolution of a reflectivity measurement 

is one kilometer or better in order that 

the locations and spatial extent of 

clouds—especially their critical 

altitudes and thicknesses—and of 

precipitation can be determined with 

sufficient accuracy for use in this 

appendix; 12

(4) Any attenuation caused by 

precipitation or an accumulation of 

water or ice on the radome that protects 

the radar antenna is less than or equal 

to 1 dBZ because the requirements in 

this appendix can be met only with that 

degree of accuracy; 13 and 

(5) A reflectivity measurement 

contains no portion of the cone of 

silence or other blocked out portion so 

that it is not giving a bogus indication.14

A launch operator who relies on 

VAHIRR to increase launch availability 

under this appendix must satisfy the 

requirements of both sections 

G417.25(a) and (b), or must otherwise 

ensure that its estimates of VAHIRR are 

at least as large as those that would 

result from section G417.25(b) to ensure 

that its invocation of any VAHIRR 

exceptions to these rules are at least as 

safe. The current requirements for 

calculating VAHIRR at the Federal 

launch ranges satisfy section G417.1(c) 

because they are more conservative, 

even though there are certain 

requirements of section G417.25(b) that 

they do not satisfy. The Federal launch 

ranges do not, as required by paragraph 

(b)(1), ensure that a digital signal 

processor provide radar reflectivity 

measurements on a three-dimensional 


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Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 33147 

15 Id. 

16Technical name for NEXRAD is WSR–88D, 

which stands for Weather Surveillance Radar, 1988, 

Doppler. 

17A History of the Lightning Criteria, 124, par. J. 

18 Id. (describing the interim methodology). 

Cartesian grid having a maximum gridpoint-to-grid-point spacing of one 

kilometer in each of the three 

dimensions. The ranges do, as required 

by paragraph (b)(2), ensure that the 

specified volume is bounded in the 

horizontal by vertical plane, 

perpendicular sides located 5.5 

kilometers (3 nautical miles) north, east, 

south, and west of the point where 

VAHIRR is to be evaluated; on the 

bottom by the 0 degree Celsius level; 

and on the top by an altitude of 

18 kilometers.15 Note that the specified 

volume need not contain the VAHIRR 

evaluation point, which may be either 

below the lower boundary of that 

volume (as when the vehicle is on the 

launch pad) or above the upper 

boundary (as when the vehicle is flying 

high above an anvil cloud) of the 

specified volume. 

To calculate VAHIRR a launch 

operator must compute both a volume 

averaged radar reflectivity and an 

average cloud thickness in a specified 

volume before multiplying them to 

obtain a value for VAHIRR. Neither of 

these quantities is available yet as an 

output product of the WSR–88D.16 or 

WSR–74C radar systems that the Federal 

ranges use to support commercial 

launches.17 Instead, the Federal ranges 

and NASA rely on Interim 

Instructions 18 for computing these 

quantities, which are more conservative 

and, thus, afford less launch availability 

than allowed by section G417.25(b). 

Paragraph (c) of section G417.25 

requires a launch operator who 

measures an electric field to comply 

with this appendix to— 

• Employ a ground-based field mill in 

order to obtain a reliable and easily 

calibrated measurement with a 

relatively low-maintenance instrument; 

• Use only the one-minute arithmetic 

average of the instantaneous readings 

from that field mill to minimize the 

effects of local space charge and 

lightning field changes; 

• Ensure that all field mills are 

calibrated so that the polarity of the 

electric field measurements is the same 

as the polarity of a voltage placed on a 

test plate above the sensor as discussed 

in more detail below; 

• Ensure that the altitude of the flight 

path of the launch vehicle is equal to or 

less than 20 kilometers (66 thousand 

feet) everywhere above a horizontal 

circle of 5 nautical miles centered on 

the field mill being used as discussed 

further below, and 

• Use only direct measurements from 

a field mill. A launch operator may not 

interpolate based on electric-field 

contours because interpolation schemes 

are highly variable and can give 

unexpected results. 

The Federal launch ranges use electric 

field mills that satisfy each of the 

requirements of paragraph (c) of section 

G417.25. Accordingly, no new 

methodology is being codified here. 

Regarding the polarity of an electric 

field measurement, note that the 

required polarity is the opposite of the 

so-called ‘‘physics sign convention’’ that 

is now used almost exclusively in the 

atmospheric electricity literature. This 

older sign convention is retained here, 

however, because it has been in 

exclusive use at the Kennedy Space 

Center and the Eastern Range since the 

early days of the Launch Pad Lightning 

Warning System and it remains in use 

today. 

The FAA is relaxing the requirements 

for field measurement by limiting the 

altitude of the flight path of the launch 

vehicle to less than 20 kilometers (66 

thousand feet) everywhere above a 

horizontal circle of 5 nautical miles 

centered on the field mill. Electric field 

measurements above 20 kilometers are 

to be ignored. 

Small Business Regulatory Enforcement 

Fairness Act 

The Small Business Regulatory 

Enforcement Fairness Act (SBREFA) of 

1996 requires the FAA to comply with 

small entity requests for information or 

advice about compliance with statutes 

and regulations within its jurisdiction. 

Therefore, any small entity that has a 

question regarding this document may 

contact their local FAA official, or the 

person listed under FOR FURTHER

INFORMATION CONTACT. You can find out 

more about SBREFA on the Internet at 

http://www.faa.gov/ 

regulations_policies/rulemaking/ 

sbre_act/. 

IV. Regulatory Analyses 

Paperwork Reduction Act 

The Paperwork Reduction Act of 1995 

(44 U.S.C. 3507(d)) requires that the 

FAA consider the impact of paperwork 

and other information collection 

burdens imposed on the public. The 

FAA has determined that this final rule 

has no new additional burden to 

respondents over and above that which 

the Office of Management and Budget 

already approved under the existing 

rule titled, ‘‘Commercial Space 

Transportation Licensing Regulations’’ 

(OMB 2120–0608). 

International Compatibility 

The FAA has determined that a 

review of the Convention on 

International Civil Aviation Standards 

and Recommended Practices is not 

warranted because there is not a 

comparable rule under ICAO standards. 

Regulatory Evaluation, Regulatory 

Flexibility Determination, International 

Trade Regulatory Flexibility 

Determination 

Changes to Federal regulations must 

undergo several economic analyses. 

First, Executive Order 12866 directs that 

each Federal agency may propose or 

adopt a regulation only upon a reasoned 

determination that the benefits of the 

intended regulation justify its costs. 

Second, the Regulatory Flexibility Act 

of 1980 (Pub. L. 96–354) requires 

agencies to analyze the economic 

impact of regulatory changes on small 

entities. Third, the Trade Agreements 

Act (Pub. L. 96–39) prohibits agencies 

from setting standards that create 

unnecessary obstacles to the foreign 

commerce of the United States. In 

developing U.S. standards, the Trade 

Act requires agencies developing 

standards to consider international 

standards and, where appropriate, that 

they be the basis of U.S. standards. 

Fourth, the Unfunded Mandates Reform 

Act of 1995 (Pub. L. 104–4) requires 

agencies to prepare a written assessment 

of the costs, benefits, and other effects 

of proposed or final rules that include 

a Federal mandate likely to result in the 

expenditure by State, local, or tribal 

governments, in the aggregate, or by the 

private sector, of $100 million or more 

annually (adjusted for inflation with 

base year of 1995). This portion of the 

preamble summarizes the FAA’s 

analysis of the economic impacts of this 

direct final rule. 

Department of Transportation Order 

DOT 2100.5 prescribes policies and 

procedures for simplification, analysis, 

and review of regulations. If the 

expected cost impact is so minimal that 

a proposed or final rule does not 

warrant a detailed evaluation, this order 

permits that a statement to that effect 

and the basis for it be included in the 

preamble if a full regulatory evaluation 

of the cost and benefits is not prepared. 

Such a determination has been made for 

this direct final rule. The reasoning for 

this determination follows. Note that the 

following discussion represents a gross 

simplification of the new requirements 

and that there is no safe substitute for 

reading the rules themselves. 

These changes are being made 

because studies and data that were not 

available when the current regulations 


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33148 Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 

were established have led the FAA to 

conclude that the intended level of 

safety can be maintained with fewer 

constraints on launch through and near 

anvil and debris clouds. 

The FAA concluded from studies that 

a launch vehicle will not trigger 

lightning in a steady electric field with 

a magnitude of less than 3 kV/m. 

Furthermore, the Lightning Advisory 

Panel performed analyses which 

support the conclusion that the 

possibility of encountering electric field 

magnitudes of more than 3 kV/m is very 

small if the flight path is more than 3 

nautical miles from an anvil or debris 

cloud’s edge, provided that all other 

sections of Appendix G are also 

satisfied. Furthermore, quantitative 

studies from the LAP indicate that, if 

the VAHIRR is less than 10 dBZ-km 

(about 33 dBZ-kft), the probability of an 

electric field of greater than 3 kV/m 

occurring is less than 1 in 10,000 under 

these conditions. 

With this rule, launch initiation may 

occur sooner and certainly no later than 

under current regulations. There will be 

fewer constraints on launch initiation 

because in some situations, fewer 

conditions will be needed to meet 

criteria for launch initiation and in 

other situations; alternative conditions 

that meet prescribed criteria will be 

accepted for launch initiation. 

Therefore, the rule will increase launch 

availability and likely decrease costs. 

The direct final rule adds a section 

(G417.25) which describes the methods 

for calculating the VAHIRR currently 

accepted by the FAA. These precise 

methods are not prescribed in the 

current Code of Federal Regulations. 

The direct final rule codifies VAHIRR 

calculation methods and recognizes as 

acceptable the method used by the 

federal launch ranges, and therefore 

increases clarity. The direct final rule 

also reorganizes rule language and adds 

and changes definitions to enhance 

clarity of the rule language. 

Since this direct final rule will be cost 

relieving without degrading safety, a 

regulatory evaluation was not prepared. 

FAA has, therefore, determined that this 

direct final rule is not a ‘‘significant 

regulatory action’’ as defined in section 

3(f) of Executive Order 12866, and is not 

‘‘significant’’ as defined in DOT’s 

Regulatory Policies and Procedures. 

Regulatory Flexibility Determination 

The Regulatory Flexibility Act of 1980 

(Pub. L. 96–354) (RFA) establishes ‘‘as a 

principle of regulatory issuance that 

agencies shall endeavor, consistent with 

the objectives of the rule and of 

applicable statutes, to fit regulatory and 

informational requirements to the scale 

of the businesses, organizations, and 

governmental jurisdictions subject to 

regulation. To achieve this principle, 

agencies are required to solicit and 

consider flexible regulatory proposals 

and to explain the rationale for their 

actions to assure that such proposals are 

given serious consideration.’’ The RFA 

covers a wide-range of small entities, 

including small businesses, not-forprofit organizations, and small 

governmental jurisdictions. 

Agencies must perform a review to 

determine whether a rule will have a 

significant economic impact on a 

substantial number of small entities. If 

the agency determines that it will, the 

agency must prepare a regulatory 

flexibility analysis as described in the 

RFA. 

However, if an agency determines that 

a rule is not expected to have a 

significant economic impact on a 

substantial number of small entities, 

section 605(b) of the RFA provides that 

the head of the agency may so certify 

and a regulatory flexibility analysis is 

not required. The certification must 

include a statement providing the 

factual basis for this determination, and 

the reasoning should be clear. 

This direct final rule is cost relieving, 

and thus is not expected to have a 

significant economic impact. Therefore 

as FAA Administrator, I certify this rule 

will not have a significant economic 

impact on a substantial number of small 

entities. 

International Trade Impact Assessment 

The Trade Agreements Act of 1979 

(Pub. L. 96–39), as amended by the 

Uruguay Round Agreements Act (Pub. 

L. 103–465), prohibits Federal agencies 

from establishing standards or engaging 

in related activities that create 

unnecessary obstacles to the foreign 

commerce of the United States. 

Pursuant to these Acts, the 

establishment of standards is not 

considered an unnecessary obstacle to 

the foreign commerce of the United 

States, so long as the standard has a 

legitimate domestic objective, such as 

the protection of safety, and does not 

operate in a manner that excludes 

imports that meet this objective. The 

statute also requires consideration of 

international standards and, where 

appropriate, that they be the basis for 

U.S. standards. The FAA has found no 

comparable international standards. The 

FAA has assessed the potential effect of 

this direct final rule and determined 

that it will have only a domestic impact 

and therefore no affect on international 

trade. 

Unfunded Mandates Assessment 

Title II of the Unfunded Mandates 

Reform Act of 1995 (Pub. L. 104–4) 

requires each Federal agency to prepare 

a written statement assessing the effects 

of any Federal mandate in a proposed or 

final agency rule that may result in an 

expenditure of $100 million or more (in 

1995 dollars) in any one year by State, 

local, and tribal governments, in the 

aggregate, or by the private sector; such 

a mandate is deemed to be a ‘‘significant 

regulatory action.’’ The FAA currently 

uses an inflation-adjusted value of 

$140.8 million in lieu of $100 million. 

This direct final rule does not contain 

such a mandate; therefore, the 

requirements of Title II of the Act do not 

apply. 

Executive Order 13132, Federalism 

The FAA has analyzed this final rule 

under the principles and criteria of 

Executive Order 13132, Federalism. We 

determined that this action will not 

have a substantial direct effect on the 

States, or the relationship between the 

national government and the States, or 

on the distribution of power and 

responsibilities among the various 

levels of government. Therefore, we 

determined that this final rule does not 

have federalism implications. 

Environmental Analysis 

FAA Order 1050.1E identifies FAA 

actions that are categorically excluded 

from preparation of an environmental 

assessment or environmental impact 

statement under the National 

Environmental Policy Act in the 

absence of extraordinary circumstances. 

The FAA has determined this 

rulemaking action qualifies for the 

categorical exclusion identified in 

Chapter 3, paragraph 312d, governing 

rulemakings such as this, and involves 

no extraordinary circumstances. 

Regulations That Significantly Affect 

Energy Supply, Distribution, or Use 

The FAA has analyzed this final rule 

under Executive Order 13211, Actions 

Concerning Regulations that 

Significantly Affect Energy Supply, 

Distribution, or Use, 66 FR 28355 (May 

18, 2001). We have determined that it is 

not a ‘‘significant energy action’’ under 

the executive order because it is not a 

‘‘significant regulatory action’’ under 

Executive Order 12866, and it is not 

likely to have a significant adverse effect 

on the supply, distribution, or use of 

energy. 

List of Subjects in 14 CFR Part 417 

Space Safety, Space transportation 

and exploration. 


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Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 33149 

The Amendments 

In consideration of the foregoing, the 

Federal Aviation Administration 

amends Chapter I of Title 14 Code of 

Federal Regulations as follows: 

PART 417—LAUNCH SAFETY 

■ 1. The authority citation for part 417 

is revised to read as follows: 

Authority: 51 U.S.C. 50901–50923. 

■ 2. Revise Appendix G to read as 

follows: 

Appendix G to Part 417—Natural and 

Triggered Lightning Flight Commit 

Criteria 

G417.1 General 

This appendix provides flight commit 

criteria for mitigating against natural 

lightning strikes and lightning triggered by 

the flight of a launch vehicle through or near 

an electrified environment. A launch 

operator may not initiate flight unless the 

weather conditions at the time of launch 

satisfy all lightning flight commit criteria of 

this appendix. 

(a) In order to meet the lightning flight 

commit criteria, a launch operator must 

employ any: 

(1) Weather monitoring and measuring 

equipment needed, and 

(2) Procedures needed to verify 

compliance. 

(b) When equipment or procedures, such as 

a field mill or calculation of the volumeaveraged, height-integrated radar reflectivity 

(VAHIRR) of clouds, are used with the 

lightning flight commit criteria to increase 

launch opportunities, a launch operator must 

evaluate all applicable measurements to 

determine whether the measurements satisfy 

the criteria. A launch operator may not turn 

off available instrumentation to create the 

appearance of meeting a requirement and 

must use all radar reflectivity measurements 

within a specified volume for a VAHIRR 

calculation. 

(c) If a launch operator proposes any 

alternative lightning flight commit criteria, 

the launch operator must clearly and 

convincingly demonstrate that the alternative 

provides an equivalent level of safety to that 

required by this appendix. 

G417.3 Definitions 

For the purpose of this appendix: 

Anvil cloud means a stratiform or fibrous 

cloud formed by the upper-level outflow or 

blow-off from a thunderstorm or convective 

cloud. 

Associated means two or more clouds are 

caused by the same disturbed weather or are 

physically connected. 

Bright band means an enhancement of 

radar reflectivity caused by frozen 

hydrometeors falling and beginning to melt at 

any altitude where the temperature is 0 

degrees Celsius or warmer. 

Cloud means a visible mass of suspended 

water droplets or ice crystals, or a 

combination of water droplets and ice 

crystals. The cloud is the entire volume 

containing such particles. 

Cloud layer means a vertically continuous 

array of clouds, not necessarily of the same 

type, whose bases are approximately at the 

same altitude. 

Cone of silence means the volume within 

which a radar cannot detect any object, and 

is an inverted circular cone centered on the 

radar antenna. A cone of silence consists of 

all elevation angles greater than the 

maximum elevation angle reached by the 

radar. 

Debris cloud means any cloud, except an 

anvil cloud, that has become detached from 

a parent cumulonimbus cloud or 

thunderstorm, or that results from the decay 

of a parent cumulonimbus cloud or 

thunderstorm. 

Disturbed weather means a weather system 

where a dynamical process destabilizes the 

air on a scale larger than the individual 

clouds or cells. Examples of disturbed 

weather include fronts, troughs, and squall 

lines. 

Electric field means a vertical electric field 

(Ez) at the surface of the Earth. 

Field mill means an electric-field sensor 

that uses a moving, grounded conductor to 

induce a time-varying electric charge on one 

or more sensing elements in proportion to the 

ambient electrostatic field. 

Flight path means a launch vehicle’s 

planned flight trajectory, and includes the 

trajectory’s vertical and horizontal 

uncertainties resulting from all three-sigma 

guidance and performance deviations. 

Horizontal distance means a distance that 

is measured horizontally between a field mill 

or electric field measurement point and the 

nearest part of the vertical projection of an 

object or flight path onto the surface of the 

Earth. 

Moderate precipitation means a 

precipitation rate of 0.1 inches/hr or a radar 

reflectivity of 30 dBZ. 

Non-transparent means that one or more of 

the following conditions apply: 

(1) Objects above, including higher clouds, 

blue sky, and stars, are blurred, indistinct, or 

obscured when viewed from below when 

looking through a cloud at visible 

wavelengths; or objects below, including 

terrain, buildings, and lights on the ground, 

are blurred, indistinct, or obscured when 

viewed from above when looking through a 

cloud at visible wavelengths; 

(2) Objects above an observer are seen 

distinctly only through breaks in a cloud; or 

(3) The cloud has a radar reflectivity of 0 

dBZ or greater. 

Precipitation means detectable rain, snow, 

hail, graupel, or sleet at the ground; virga; or 

a radar reflectivity greater than 18 dBZ. 

Radar reflectivity means the radar 

reflectivity factor due to hydrometeors, in 

dBZ. 

Slant distance means the shortest distance 

between two ports, whether horizontal, 

vertical, or inclined, in three dimensional 

space. 

Thick cloud layer means one or more cloud 

layers whose combined vertical extent from 

the base of the bottom cloud layer to the top 

of the uppermost cloud layer exceeds 4,500 

feet. Cloud layers are combined with 

neighboring layers for determining total 

thickness only when they are physically 

connected by vertically continuous clouds. 

Thunderstorm means any convective cloud 

that produces lightning. 

Transparent means that any of the 

following conditions apply: 

(1) Objects above, including higher clouds, 

blue sky, and stars, are not blurred, are 

distinct and are not obscured when viewed 

at visible wavelengths; or objects below, 

including terrain, buildings, and lights on the 

ground, are clear, distinct, and not obscured 

when viewed at visible wavelengths; (2) 

Objects identified in paragraph (1) of this 

definition are seen distinctly not only 

through breaks in a cloud; and (3) The cloud 

has a radar reflectivity of less than 0 dBZ. 

Triboelectrification means the transfer of 

electrical charge between ice particles and a 

launch vehicle when the ice particles collide 

with the vehicle during flight. 

Volume-averaged, height integrated radar 

reflectivity (VAHIRR) means the product, 

expressed in units of dBZ-km or dBZ-kft, of 

a volume-averaged radar reflectivity and an 

average cloud thickness in a specified 

volume corresponding to a point. 

G417.5 Lightning 

(a) A launch operator must wait 30 minutes 

to initiate flight after any type of lightning 

occurs in a thunderstorm if the flight path 

will carry the launch vehicle at a slant 

distance of less than or equal to 10 nautical 

miles from that thunderstorm. This 

paragraph does not apply to an anvil cloud 

that is attached to a parent thunderstorm. 

(b) A launch operator must wait 30 

minutes to initiate flight after any type of 

lightning occurs at a slant distance of less 

than or equal to 10 nautical miles from the 

flight path, unless: 

(1) The non-transparent part of the cloud 

that produced the lightning is at a slant 

distance of greater than 10 nautical miles 

from the flight path; 

(2) There is at least one working field mill 

at a horizontal distance of less than or equal 

to 5 nautical miles from each such lightning 

discharge; and 

(3) The absolute values of all electric field 

measurements at a horizontal distance of less 

than or equal to 5 nautical miles from the 

flight path and at each field mill specified in 

paragraph (b)(2) of this section have been less 

than 1000 volts/meter for at least 15 minutes. 

G417.7 Cumulus Clouds 

(a) This section applies to non-transparent 

cumulus clouds, except for cirrocumulus, 

altocumulus, or stratocumulus clouds. This 

section does not apply to an anvil cloud that 

is attached to a parent cumulus cloud. 

(b) A launch operator may not initiate 

flight if the slant distance to the flight path 

is less than or equal to 10 nautical miles from 

any cumulus cloud that has a top at an 

altitude where the temperature is colder than 

or equal to ¥20 degrees Celsius. 

(c) A launch operator may not initiate 

flight if the slant distance to the flight path 

is less than or equal to 5 nautical miles from 

any cumulus cloud that has a top at an 

altitude where the temperature is colder than 

or equal to ¥10 degrees Celsius. 

(d) A launch operator may not initiate 

flight if the flight path will carry the launch 

vehicle through any cumulus cloud with its 


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33150 Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 

top at an altitude where the temperature is 

colder than or equal to ¥5 degrees Celsius. 

(e) A launch operator may not initiate 

flight if the flight path will carry the launch 

vehicle through any cumulus cloud that has 

a top at an altitude where the temperature is 

colder than or equal to +5, and warmer than 

¥5 degrees Celsius unless: 

(1) The cloud is not producing 

precipitation; 

(2) The horizontal distance from the center 

of the cloud top to at least one working field 

mill is less than 2 nautical miles; and 

(3) All electric field measurements at a 

horizontal distance of less than or equal to 

5 nautical miles of the flight path and at each 

field mill specified in paragraph (e)(2) of this 

section have been between ¥100 volts/meter 

and +500 volts/meter for at least 15 minutes. 

G417.9 Attached Anvil Clouds 

(a) This section applies to any nontransparent anvil cloud formed from a parent 

cloud that has a top at an altitude where the 

temperature is colder than or equal to ¥10 

degrees Celsius. 

(b) Flight path through cloud: If a flight 

path will carry a launch vehicle through any 

attached anvil cloud, the launch operator 

may not initiate flight unless: 

(1) The portion of the attached anvil cloud 

at a slant distance of less than or equal to 5 

nautical miles from the flight path is located 

entirely at altitudes where the temperature is 

colder than 0 degrees Celsius; and 

(2) The volume-averaged, height-integrated 

radar reflectivity is less than +10 dBZ-km 

(+33 dBZ-kft) at every point at a slant 

distance of less than or equal to 1 nautical 

mile from the flight path. 

(c) Flight path between 0 and 3 nautical 

miles from cloud: If a flight path will carry 

a launch vehicle at a slant distance of greater 

than 0, but less than or equal to 3, nautical 

miles from any attached anvil cloud, a 

launch operator must wait 3 hours to initiate 

flight after a lightning discharge in or from 

the parent cloud or anvil cloud, unless: 

(1) The portion of the attached anvil cloud 

at a slant distance of less than or equal to 5 

nautical miles from the flight path is located 

entirely at altitudes where the temperature is 

colder than 0 degrees Celsius; and 

(2) The volume-averaged, height-integrated 

radar reflectivity is less than +10 dBZ-km 

(+33 dBZ-kft) at every point at a slant 

distance of less than or equal to 1 nautical 

mile from the flight path. 

(d) Flight path between 3 and 5 nautical 

miles from cloud: If a flight path will carry 

a launch vehicle at a slant distance of greater 

than 3 and less than or equal to 5 nautical 

miles from any attached anvil cloud, a 

launch operator must wait 3 hours to initiate 

flight after every lightning discharge in or 

from the parent cloud or anvil cloud, unless 

the portion of the attached anvil cloud at a 

slant distance of less than or equal to 5 

nautical miles from the flight path is located 

entirely at altitudes where the temperature is 

colder than 0 degrees Celsius. 

(e) Flight path between 5 and 10 nautical 

miles from cloud: If the flight path will carry 

the launch vehicle at a slant distance of 

greater than 5 and less than or equal to 10 

nautical miles from any attached anvil cloud, 

the launch operator must wait to initiate 

flight for 30 minutes after every lightning 

discharge in or from the parent cloud or anvil 

cloud, unless the portion of the attached 

anvil cloud at a slant distance of less than or 

equal to 10 nautical miles from the flight 

path is located entirely at altitudes where the 

temperature is colder than 0 degrees Celsius. 

G417.11 Detached Anvil Clouds 

(a) This section applies to any nontransparent anvil cloud formed from a parent 

cloud that had a top at an altitude where the 

temperature was colder than or equal to ¥10 

degrees Celsius. 

(b) Flight path through cloud: If the flight 

path will carry the launch vehicle through a 

detached anvil cloud, the launch operator 

may not initiate flight unless: 

(1) The launch operator waits 4 hours after 

every lightning discharge in or from the 

detached anvil cloud; and observation shows 

that 3 hours have passed since the anvil 

cloud detached from the parent cloud; or 

(2) Each of the following conditions exists: 

(i) Any portion of the detached anvil cloud 

at a slant distance of less than or equal to 5 

nautical miles from the flight path is located 

entirely at altitudes where the temperature is 

colder than 0 degrees Celsius; and 

(ii) The VAHIRR is less than +10 dBZ-km 

(+33 dBZ-kft) everywhere in the flight path. 

(c) Flight path between 0 and 3 nautical 

miles from cloud: If a flight path will carry 

a launch vehicle at a slant distance of greater 

than 0 and less than or equal to 3 nautical 

miles from a detached anvil cloud, the 

launch operator must accomplish both of the 

following: 

(1) Wait 30 minutes to initiate flight after 

every lightning discharge in or from the 

parent cloud or anvil cloud before 

detachment of the anvil cloud, and after 

every lightning discharge in or from the 

detached anvil cloud after detachment, 

unless: 

(i) The portion of the detached anvil cloud 

less than or equal to 5 nautical miles from 

the flight path is located entirely at altitudes 

where the temperature is colder than 0 

degrees Celsius; and 

(ii) The VAHIRR is less than +10 dBZ-km 

(+33 dBZ-kft) at every point at a slant 

distance of less than or equal to 1 nautical 

mile from the flight path; and 

(2) If a launch operator is unable to initiate 

flight in the first 30 minutes under paragraph 

(c)(1) of this section, the launch operator 

must wait to initiate flight for 3 hours after 

every lightning discharge in or from the 

parent cloud or anvil cloud before 

detachment of the anvil cloud, and after 

every lightning discharge in or from the 

detached anvil cloud after detachment, 

unless: 

(i) All of the following are true: 

(A) There is at least one working field mill 

at a horizontal distance of less than or equal 

to 5 nautical miles from the detached anvil 

cloud; 

(B) The absolute values of all electric field 

measurements at a horizontal distance of less 

than or equal to 5 nautical miles from the 

flight path and at each field mill specified in 

paragraph (c)(2)(i)(A) of this section have 

been less than 1000 V/m for at least 15 

minutes; and 

(C) The maximum radar reflectivity from 

any part of the detached anvil cloud at a slant 

distance of less than or equal to 5 nautical 

miles from the flight path has been less than 

+10 dBZ for at least 15 minutes; or 

(ii) Both of the following are true: 

(A) The portion of the detached anvil cloud 

at a slant distance of less than or equal to 5 

nautical miles from the flight path is located 

entirely at altitudes where the temperature is 

colder than 0 degrees Celsius; and 

(B) The volume-averaged, height-integrated 

radar reflectivity is less than +10 dBZ-km 

(+33 dBZ-kft) at every point at a slant 

distance of less than or equal to 1 nautical 

mile from the flight path. 

(d) Flight path between 3 and 10 nautical 

miles from cloud: If a flight path will carry 

a launch vehicle at a slant distance of greater 

than 3 and less than or equal to 10 nautical 

miles from a detached anvil cloud, the 

launch operator must wait 30 minutes to 

initiate flight after every lightning discharge 

in or from the parent cloud or anvil cloud 

before detachment, and after every lightning 

discharge in or from the detached anvil cloud 

after detachment, unless the portion of the 

detached anvil cloud at a slant distance of 

less than or equal to 10 nautical miles from 

the flight path is located entirely at altitudes 

where the temperature is colder than 0 

degrees Celsius. 

G417.13 Debris Clouds 

(a) This section applies to any nontransparent debris cloud whose parent 

cumuliform cloud has had any part at an 

altitude where the temperature was colder 

than ¥20 degrees Celsius or to any debris 

cloud formed by a thunderstorm. This 

section does not apply to a detached anvil 

cloud. 

(b) A launch operator must calculate a ‘‘3- 

hour period’’ as starting at the latest of the 

following times: 

(1) The debris cloud is observed to be 

detached from the parent cloud; 

(2) The debris cloud is observed to have 

formed by the collapse of the parent cloud 

top to an altitude where the temperature is 

warmer than ¥10 degrees Celsius; or 

(3) Any lightning discharge occurs in or 

from the debris cloud. 

(c) Flight path through cloud: If a flight 

path will carry a launch vehicle through a 

debris cloud, the launch operator may not 

initiate flight during the ‘‘3-hour period,’’ of 

paragraph (b) of this section, unless: 

(1) The portion of the debris cloud at a 

slant distance of less than or equal to 5 

nautical miles from the flight path is located 

entirely at altitudes where the temperature is 

colder than 0 degrees Celsius; and 

(2) The VAHIRR is less than +10 dBZ-km 

(+33 dBZ-kft) everywhere in the flight path. 

(d) Flight path between 0 and 3 nautical 

miles from cloud: If the flight path will carry 

the launch vehicle at a slant distance of 

greater than or equal to 0 and less than or 

equal to 3 nautical miles from the debris 

cloud, the launch operator may not initiate 

flight during the ‘‘3-hour period,’’ unless one 

of the following applies: 

(1) A launch operator may initiate flight 

during the ‘‘3-hour period,’’ of paragraph (b) 

of this section if: 


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Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 33151 

(i) There is at least one working field mill 

at a horizontal distance of less than or equal 

to 5 nautical miles from the debris cloud; 

(ii) The absolute values of all electric field 

measurements at a horizontal distance of less 

than or equal to 5 nautical miles from the 

flight path and at each field mill specified in 

paragraph (d)(1)(i) of this section have been 

less than 1000 volts/meter for at least 15 

minutes; and 

(ii) The maximum radar reflectivity from 

any part of the debris cloud less than or equal 

to a slant distance of 5 nautical miles from 

the flight path has been less than +10 dBZ 

for at least 15 minutes; or 

(2) A launch operator may initiate flight 

during the ‘‘3-hour period,’’ of paragraph (b) 

of this section if: 

(i) The portion of the debris cloud at a slant 

distance of less than or equal to 5 nautical 

miles from the flight path is located entirely 

at altitudes where the temperature is colder 

than 0 degrees Celsius; and 

(ii) The VAHIRR is less than + 10 dBZ-km 

(+33 dBZ-kft) at every point at a slant 

distance of less than or equal to 1 nautical 

mile from the flight path. 

G417.15 Disturbed Weather 

A launch operator may not initiate flight if 

the flight path will carry the launch vehicle 

through a non-transparent cloud associated 

with disturbed weather that has clouds with 

tops at altitudes where the temperature is 

colder than 0 degrees Celsius and that 

contains, at a slant distance of less than or 

equal to 5 nautical miles from the flight path, 

either: 

(a) Moderate or greater precipitation; or 

(b) Evidence of melting precipitation such 

as a radar bright band. 

G417.17 Thick Cloud Layers 

(a) This section does not apply to either 

attached or detached anvil clouds. 

(b) A launch operator may not initiate 

flight if the flight path will carry the launch 

vehicle through a non-transparent cloud 

layer that is: 

(1) Greater than or equal to 4,500 feet thick 

and any part of the cloud layer in the flight 

path is located at an altitude where the 

temperature is between 0 degrees Celsius and 

¥20 degrees Celsius, inclusive; or 

(2) Connected to a thick cloud layer that, 

at a slant distance of less than or equal to 5 

nautical miles from the flight path, is greater 

than or equal to 4,500 feet thick and has any 

part located at any altitude where the 

temperature is between 0 degrees Celsius and 

¥20 degrees Celsius, inclusive. 

(c) A launch operator may initiate flight 

despite paragraphs (a)(1) and (a)(2) of this 

section if the thick cloud layer: 

(1) Is a cirriform cloud layer that has never 

been associated with convective clouds, 

(2) Is located entirely at altitudes where the 

temperature is colder than or equal to ¥15 

degrees Celsius, and 

(3) Shows no evidence of containing liquid 

water. 

G417.19 Smoke Plumes 

(a) A launch operator may not initiate 

flight if the flight path will carry the launch 

vehicle through any non-transparent 

cumulus cloud that has developed from a 

smoke plume while the cloud is attached to 

the smoke plume, or for the first 60 minutes 

after the cumulus cloud is observed to be 

detached from the smoke plume. 

(b) This section does not apply to nontransparent cumulus clouds that have formed 

above a fire but have been detached from the 

smoke plume for more than 60 minutes. 

Section G417.7 applies. 

G417.21 Surface Electric Fields 

(a) A launch operator must wait 15 minutes 

to initiate flight after the absolute value of 

any electric field measurement at a 

horizontal distance of less than or equal to 

5 nautical miles from the flight path has been 

greater than or equal to 1500 volts/meter. 

(b) A launch operator must wait 15 

minutes to initiate flight after the absolute 

value of any electric field measurement at a 

horizontal distance of less than or equal to 

5 nautical miles from the flight path has been 

greater than or equal to 1000 volts/meter, 

unless: 

(1) All clouds at a slant distance of less 

than or equal to 10 nautical miles from the 

flight path are transparent; or 

(2) All non-transparent clouds at a slant 

distance less than or equal to 10 nautical 

miles from the flight path: 

(i) Have tops at altitudes where the 

temperature is warmer than or equal to +5 

degrees Celsius, and 

(ii) Have not been part of convective clouds 

with cloud tops at altitudes where the 

temperature was colder than or equal to ¥10 

degrees Celsius for 3 hours. 

G417.23 Triboelectrification 

(a) A launch operator may not initiate 

flight if the flight path will carry the launch 

vehicle through any part of a cloud at any 

altitude where: 

(1) The temperature is colder than or equal 

to ¥10 degrees Celsius; and 

(2) The launch vehicle’s velocity is less 

than or equal to 3000 feet/second, 

(b) Paragraph (a) of this section does not 

apply if either: 

(1) The launch vehicle is treated for surface 

electrification so that: 

(i) All surfaces of the launch vehicle 

susceptible to ice particle impact are such 

that the surface resistivity is less than 10 9

Ohms per square; and 

(ii) All conductors on surfaces, including 

dielectric surfaces that have been coated with 

conductive materials, are bonded to the 

launch vehicle by a resistance that is less 

than 10 5 ohms; or 

(2) A launch operator demonstrates by test 

or analysis that electrostatic discharges on 

the surface of the launch vehicle caused by 

triboelectrification will not be hazardous to 

the launch vehicle or the spacecraft. 

G417.25 Measurement of Cloud Radar 

Reflectivity, Computation of VAHIRR, and 

Measurement of Electric Field 

(a) Radar reflectivity measurement. A 

launch operator who measures radar 

reflectivity to comply with this appendix 

must employ a meteorological radar and 

ensure that— 

(1) The radar wavelength is greater than or 

equal to 5 cm; 

(2) A reflectivity measurement is due to a 

meteorological target; 

(3) The spatial accuracy and resolution of 

a reflectivity measurement is 1 kilometer or 

better; 

(4) Any attenuation caused by intervening 

precipitation or by an accumulation of water 

or ice on the radome is less than or equal to 

1 dBZ; and 

(5) A reflectivity measurement contains no 

portion of the cone of silence above the radar 

antenna, nor any portion of any sector that 

is blocked out for payload safety reasons. 

(b) Computation of VAHIRR. A launch 

operator who measures VAHIRR to comply 

with this appendix must ensure that— 

(1) A digital signal processor provides 

radar reflectivity measurements on a threedimensional Cartesian grid having a 

maximum grid-point-to-grid-point spacing of 

one kilometer in each of the three 

dimensions; 

(2) The specified volume is the volume 

bounded in the horizontal by vertical, plane, 

perpendicular sides located 5.5 kilometers (3 

nautical miles) north, east, south, and west 

of the point where VAHIRR is to be 

evaluated; on the bottom by the 0 degree 

Celsius level; and on the top by an altitude 

of 20 kilometers; 

(3) Volume-averaged radar reflectivity is 

the arithmetic average of the radar reflectivity 

measurements in dBZ at grid points within 

the specified volume. A launch operator 

must include each grid point within the 

specified volume in the average if and only 

if that grid point has a radar reflectivity 

measurement equal to or greater than 0 dBZ. 

If fewer than 10% of the grid points in the 

specified volume have radar reflectivity 

measurements equal to or greater than 0 dBZ, 

then the volume-averaged radar reflectivity is 

either the maximum radar reflectivity 

measurement in the specified volume, or 0 

dBZ, whichever is greater. 

(4) Average cloud thickness is the 

difference in kilometers or thousands of feet 

between an average top and an average base 

of all clouds in the specified volume, 

computed as follows: 

(i) The cloud base to be averaged is the 

higher, at each horizontal position, of either 

(A) The 0 degree Celsius altitude, or 

(B) The lowest altitude of all radar 

reflectivity measurements of 0 dBZ or greater. 

(ii) The cloud top to be averaged is the 

highest altitude of all radar reflectivity 

measurements of 0 dBZ or greater at each 

horizontal position. 

(iii) A launch operator must— 

(A) Take the cloud base at any horizontal 

position as the altitude of the corresponding 

base grid point minus half of the grid-point 

vertical separation; 

(B) Take the cloud top at that horizontal 

position as the altitude of the corresponding 

top grid point plus half of this vertical 

separation. 

(5) All VAHIRR-evaluation points in the 

flight path itself are: 

(i) Greater than a slant distance of 10 

nautical miles from any radar reflectivity of 

35 dBZ or greater at altitudes of 4 kilometers 

or greater above mean sea level; and 

(ii) Greater than a slant distance of 10 

nautical miles from any type of lightning that 

has occurred in the previous 5 minutes. 


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33152 Federal Register / Vol. 76, No. 110 / Wednesday, June 8, 2011 / Rules and Regulations 

(iii) A launch operator need not apply 

paragraph (b)(5) of this section to VAHIRR 

evaluation points outside the flight path but 

within one nautical mile of the flight path. 

(6) VAHIRR is the product, expressed in 

units of dBZ-km or dBZ-kft, of the volumeaveraged radar reflectivity defined in 

paragraph (b)(3) of this section and the 

average cloud thickness defined in paragraph 

(b)(4) of this section in the specified volume 

defined in paragraph (b)(2) of this section. 

(c) Electric field measurement. A launch 

operator who measures an electric field to 

comply with this appendix must— 

(1) Employ a ground-based field mill, 

(2) Use only the one-minute arithmetic 

average of the instantaneous readings from 

that field mill, 

(3) Ensure that all field mills are calibrated 

so that the polarity of the electric field 

measurements is the same as the polarity of 

a voltage placed on a test plate above the 

sensor, 

(4) Ensure that the altitude of the flight 

path of the launch vehicle is equal to or less 

than 20 kilometers (66 thousand feet) 

everywhere above a horizontal circle of 5 

nautical miles centered on the field mill 

being used, 

(5) Use only direct measurements from a 

field mill, and 

(6) Not interpolate based on electric-field 

contours. 

Issued in Washington, DC, on May 23, 

2011. 

J. Randolph Babbitt, 

Administrator. 

[FR Doc. 2011–14146 Filed 6–7–11; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF HOMELAND 

SECURITY 

Coast Guard 

33 CFR Part 165 

[Docket No. USCG–2011–0265] 

RIN 1625–AA00 

Safety Zone; Michigan Bankers 

Association Fireworks, Lake Huron, 

Mackinac Island, MI 

AGENCY: Coast Guard, DHS. 

ACTION: Temporary final rule. 

SUMMARY: The Coast Guard is 

establishing a temporary safety zone in 

the Captain of the Port Sault Sainte 

Marie zone. This zone is intended to 

restrict vessels from certain portions of 

water areas within Sector Sault Sainte 

Marie Captain of the Port zone, as 

defined by 33 CFR 3.45–45. This 

temporary safety zone is necessary to 

protect spectators and vessels from the 

hazards associated with fireworks 

displays. 

DATES: This rule is effective from 9 p.m. 

to 11 p.m. on June 23, 2011. 

ADDRESSES: Comments and material 

received from the public, as well as 

documents mentioned in this preamble 

as being available in the docket, are part 

of docket USCG–2011–0265 and are 

available online by going to http:// 

www.regulations.gov, inserting USCG– 

2011–0265 in the ‘‘Keyword’’ box, and 

then clicking ‘‘Search’’. They are also 

available for inspection or copying at 

the Docket Management Facility (M–30), 

U.S. Department of Transportation, 

West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue SE., 

Washington, DC 20590, between 9 a.m. 

and 5 p.m., Monday through Friday, 

except Federal holidays. 

FOR FURTHER INFORMATION CONTACT: If 

you have questions on this temporary 

rule, call or email BMC Gregory Ford, 

Prevention Department, Coast Guard, 

Sector Sault Sainte Marie, MI, telephone 

(906) 635–3222, email 

Gregory.C.Ford@uscg.mil. If you have 

questions on viewing or submitting 

material to the docket, call Renee V. 

Wright, Program Manager, Docket 

Operations, telephone 202–366–9826. 

SUPPLEMENTARY INFORMATION: 

Regulatory Information 

On April 20, 2011, we published a 

notice of proposed rulemaking (NPRM) 

entitled Safety Zone; Michigan Bankers 

Association Fireworks, Lake Huron, 

Mackinac Island, Michigan, in the 

Federal Register (76 FR 22064). We 

received 0 public submissions 

commenting on the proposed rule. No 

public meeting was requested, and none 

was held. 

Under 5 U.S.C. 553(d)(3), the Coast 

Guard finds that good cause exists for 

making this rule effective less than 30 

days after publication in the Federal 

Register. Delaying the effective date of 

this rule would be impracticable and 

contrary to the public interest because it 

would inhibit the Coast Guard from 

ensuring the safety of vessels and the 

public during the fireworks display. 

Background and Purpose 

From June 21, 2011 through June 24, 

2011, the Michigan Bankers 

Association’s will celebrate its 125th 

anniversary. The celebration will take 

place on and around Mackinac Island. 

On the evening of June 23, 2011, the 

celebration will include a fireworks 

display to be launched from a water 

location. The Captain of the Port Sault 

Sainte Marie has determined that the 

fireworks event poses various hazards to 

the public, including obstructions to the 

navigable channel, explosive dangers 

associated with fireworks, and debris 

falling into the water. To minimize 

these and other hazards, this rule will 

establish a temporary safety zone 

around the fireworks display. 

Discussion of Comments and Changes 

The Coast Guard received 0 public 

submissions commenting on this rule. 

Regulatory Analyses 

We developed this rule after 

considering numerous statutes and 

executive orders related to rulemaking. 

Below we summarize our analyses 

based on 13 of these statutes or 

executive orders. 

Regulatory Planning and Review 

This rule is not a significant 

regulatory action under section 3(f) of 

Executive Order 12866, Regulatory 

Planning and Review, and does not 

require an assessment of potential costs 

and benefits under section 6(a)(3) of that 

Order. The Office of Management and 

Budget has not reviewed it under that 

Order. It is not ‘‘significant’’ under the 

regulatory policies and procedures of 

the Department of Homeland Security 

(DHS). We conclude that this rule is not 

a significant regulatory action because 

we anticipate that it will have minimal 

impact on the economy, will not 

interfere with other agencies, will not 

adversely alter the budget of any grant 

or loan recipients, and will not raise any 

novel legal or policy issues. The safety 

zone created by this rule will be 

relatively small and enforced for 

relatively short time. Also, the safety 

zone is designed to minimize its impact 

on navigable waters. Furthermore, the 

safety zone has been designed to allow 

vessels to transit around it. Thus, 

restrictions on vessel movement within 

that particular area are expected to be 

minimal. Under certain conditions, 

moreover, vessels may still transit 

through the safety zone when permitted 

by the Captain of the Port. 

Small Entities 

Under the Regulatory Flexibility Act 

(5 U.S.C. 601–612), we have considered 

whether this rule would have a 

significant economic impact on a 

substantial number of small entities. 

The term ‘‘small entities’’ comprises 

small businesses, not-for-profit 

organizations that are independently 

owned and operated and are not 

dominant in their fields, and 

governmental jurisdictions with 

populations of less than 50,000. 

The Coast Guard certifies under 5 

U.S.C. 605(b) that this rule will not have 

a significant economic impact on a 

substantial number of small entities. On 

April 20, 2011, the Coast Guard 

published a notice of proposed 


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