Advisory 

Circular 

SUBJECT: OUTDOOR LASER OPERATIONS Date: 12/30/04

Initiated by: AFS-400/ 

ATO-R

AC No: 70-1 

Change:

1. PURPOSE.

a. This Advisory Circular (AC) provides

information for those proponents planning to conduct 

outdoor laser operations that may affect aircraft

operations in the National Airspace System (NAS). 

Also, the AC explains why notification to the Federal 

Aviation Administration (FAA) is necessary, how to 

notify the FAA of the planned laser operation, and 

what action the FAA will take to respond to such 

notifications. 

b. In addition, to assist proponents in providing 

information to be used by the FAA in its review of

outdoor laser operations, the AC includes: 

• Appendix 1: 

3⁄4 Notice of Proposed Outdoor Laser

Operation(s) and Instructions; 

3⁄4 Tables 1, 2, and 3, Maximum Permissible 

Exposure Limits;

3⁄4 Tables 4 and 5, Correction Factors;

3⁄4 Graphic Examples and Descriptions of

Airspace Flight Zones;

• Appendix 2: FAA Regional Office Addresses; 

and 

• Appendix 3: Glossary. 

c. The FAA’s interest in these types of 

operations does not supercede or invalidate any

existing rules or ordinances promulgated by other

Federal, state, county, or local government. The

proponent is responsible for compliance with these 

requirements. 

2. AUTHORITY. 

 a. The FAA has the authority to regulate the 

safe and efficient use of the navigable airspace (Title 

49 U.S.C., Section 40103, Sovereignty and Use of

Airspace, and the Public Right of Transit. 

 b. The Food and Drug Administration (FDA)

has the authority to regulate light emitting products 

and electronic product radiation (Title 21, U.S.C. 

Section 360hh.).

3. EFFECTIVE DATE. This advisory circular 

becomes effective December 30, 2004. 

4. NOTIFICATION FORM. 

a. Why is it necessary to Notify the FAA?

(1) In recognition of the FAA’s role in 

promoting aviation safety, the FDA requires notice to

the FAA as a condition of a variance for outdoor

laser operations. 

(2) Early notice of the planned activity

provides the FAA the opportunity to minimize the 

potentially hazardous adverse effects of laser 

operations on aircraft operators in the navigable

airspace. The possible effects are flash blindness and 

afterimage created when a laser beam interferes with

the vision of the pilot or air crewmember, and glare

when the laser beam illuminates the windshield of an 

aircraft.

(3) The FAA recognizes that there are

varied demands for the use of airspace, both by 

aviation and non-aviation interests. While a sincere 

effort is made to find equitable solutions to conflicts

over the use of this national resource, the FAA must 

give primary consideration to aviation operations. 

b. Who should file a Notice?

Any person/proponent who plans to conduct laser

operations in the navigable airspace should file notice

with the FAA. Navigable airspace is airspace above

the minimum altitudes of flight prescribed by

regulations including airspace needed for the takeoff

and landing of aircraft (49 U.S.C. Section 40102). 
AC 70-1 12/30/04

c. When should the Notice be Filed? 

Notice should be filed as early as possible, and at 

least 30 days before the planned event in order to

allow the FAA sufficient time to accomplish an

aeronautical study and make a determination 

regarding the planned activity. 

d. Where to File the Notice? 

Notice should be filed with the appropriate FAA 

regional office. A list of regional office addresses

and the states they are responsible for is provided in

Appendix 2.

e. What Information should be submitted

to the FAA?

The FAA requests the proponent submit the

following information:

 (1) If applicable, a variance from the FDA. 

(2) A completed “Notice of Proposed 

Outdoor Laser Operation(s)” including a completed 

“Laser Configuration Worksheet” for each laser. 

(3) Detailed diagrams depicting the planned

laser paths. 

NOTE: United States Geological Survey 

quadrangle maps are available from:

U.S. Geological Survey, 

Reston, Virginia 22092

Telephone No. (703) 860-6045

 or 

 District Branch 

P.O. Box 25286, Bldg. #41 

Denver, Colorado 80225 

Telephone No. (303) 844-4169

f. What Action will the FAA take regarding

this Information? 

(1) The FAA regional Air Traffic Divisions

(ATD) are responsible for conducting an aeronautical

study to evaluate the potential effect of the planned 

outdoor laser activity on users of the navigable

airspace. 

(2) The aeronautical study determination 

will be provided in a Letter of Determination (LOD) 

to the proponent. The determination is either 

“objectionable” or “non-objectionable” with respect 

to the laser activity’s effect on users of the navigable 

airspace. 

5. RELATED DOCUMENTS. 

a. TITLE 49 U.S.C., Subtitle VII, 

AVIATION PROGRAMS, Part A - (Air Commerce 

and Safety) & Part B - (Airport Development and

Noise)

b. FAA Order 7400.2, Procedures for 

Handling Airspace Matters. 

c FDA 223-99-6000, Memorandum of

Understanding between the Food and Drug 

Administration and the Federal Aviation 

Administration (available on the FDA CDRH web

site). 

d. 21 CFR Part 1010, Performance Standards

for Electronic Products, and Part 1040, Performance 

Standards for Light Emitting Products. 

e. HHS Publication FDA 86-8261, Laser

Light Show Safety – Who’s Responsibility?

(Available on the FDA CDRH web site). 

f. American National Standards Institute 

(ANSI) Z136 series of standards. 

g. Society of Automotive Engineers, Inc.

(SAE) Aerospace Standard, AS4970, Human

Factors Considerations for Outdoor Laser Operations

in the Navigable Airspace. 

h. SAE Aerospace Recommended Practice, 

ARP5290, Laser Beam Divergence Measurements 

Techniques Comparison. 

6. ADMINISTRATIVE ASSISTANCE. 

Airspace specialists are available in each regional

office to assist proponents on non-technical matters

such as filing their notice. It should be also noted 

that limited resources might prevent the specialist 

from responding spontaneously without advance 

planning or preparation. Address technical questions

in regard to the Laser Configuration Worksheet and

Tables 1-5 to the manufacturer and /or the FDA.

7. PAPERWORK REDUCTION ACT STATEMENT.

a. Through use of this AC, the FAA intends 

to maintain a high level of safety between laser 

operations and aircraft operations. The FAA is

Page 2 Par 4 
12/30/04 AC 70-1 

requesting that laser operators submit information on

a voluntary basis using the form listed in this AC. 

b. It will take the proponent approximately 10

hours to provide the necessary information for the 

initial system analysis. The time should decrease 

/s/ John M. Allen for 

James J. Ballough 

Director, Flight Standards Service, AFS-1 

with subsequent submissions for the use of the same

laser system by the same respondent. A person is not 

required to respond to an information collection

request unless it displays a currently valid Office of

Management and Budget (OMB) number. The OMB

control number assigned to this request is 2120-0662. 

/s/ Stephen P. Creamer 

Acting Director, System Operations and Safety, 

ATO-R 

Par 7 Page 3 (and 4) 

12/30/04 AC-70-1 

 Appendix 1 

APPENDIX 1 

Notice of Proposed Outdoor 

Laser Operation(s) and Instructions 

Tables 1, 2, and 3, 

Maximum Permissible exposure Limits 

Tables 4 and 5, Correction Factors 

Graphic Examples and Descriptions 

of Airspace Flight Zones 

Page 1 (and 2)

12/30/04 AC-70-1 

 Appendix 1 

 Page 3 

 
AC 70-1 12/30/04 

Appendix 1 

INSTRUCTIONS FOR COMPLETING NOTICE OF PROPOSED 

OUTDOOR LASER OPERATION(S) 

The information on this form will be used by the FAA Regional Office to perform an aeronautical study to evaluate the safety of a 

proposed laser operation. Provide all information that may be needed to perform the study. If additional details are necessary, list 

these in the “ATTACHMENTS” section of this form. 

1. GENERAL INFORMATION - In 1.(a), enter the name, address, telephone, and fax numbers of the FAA Regional Office Air 

Traffic Division responsible for the area which includes the laser operation site. (A list of regional offices is available in APPENDIX

3 of this circular.) In 1.(b), enter the proponent's name, address, telephone, fax, and E-mail information. This is the party primarily 

responsible for the laser safety of this operation. When the proponent is a manufacturer or a governmental agency (e.g., NASA), and 

the laser is located at a different site, list the proponent here. In 1.(c), enter the event name (for temporary shows) or the facility name

(for permanent installations). In 1.(d), enter the date the report is prepared or sent to FAA. It is not the date of the laser operation. - If

the laser user is different than the proponent, fill in section 1.(e) Customer; if not, enter “Same as proponent.” In 1.(f) enter the site

address. 

2. DATE(S) AND TIME(S) OF LASER OPERATION - Enter the dates and times of testing alignment procedures, and 

operation. 

3. BRIEF DESCRIPTION OF OPERATION - The description should be a general overview of the operation. Specific laser 

configurations of the operation are described in detail using the Laser Configuration Worksheet on page 2. If necessary, attach 

additional pages.

4. ON-SITE OPERATION INFORMATION - List names and/or titles of operators. There should be at least one working, direct

telephone link to the operator, or equivalent way of quickly reaching the operator (e.g., telephoning a central station that reaches

operator via radio). Two telephone numbers are requested on the form; the number in 2.(c) should be used as an alternate or backup. 

5. FDA CDRH LASER LIGHT SHOW VARIANCE - List the variance number, accession number, and variance date if the 

operation uses or is a “demonstration laser” (generally, a laser light show) and therefore, is regulated by the Food and Drug

Administration’s Center for Devices and Radiological Health.

6. BRIEF DESCRIPTION OF CONTROL MEASURES - Describe the method(s) used to protect airspace; for example, 

termination on a building (where the beam path is not accessible by aircraft including helicopters), use of observers, use of radar and 

imaging equipment, physical methods of limiting the beam path, etc. The more the operation relies on the control measures to ensure 

safety, the more detailed the description should be. 

7. ATTACHMENTS – In 7.(a) list the number of “Laser Configurations” you are submitting with this notice. If a particular setup

operates with more than one laser, with different beam characteristics (power settings, pulse modes, divergence, etc.) or has multiple

output devices (example: projector heads), then each should be analyzed as a separate Laser Configuration. In 7.(b) list all additional 

attachments which are included to assist the FAA in sufficiently evaluating the proposal, such as maps, diagrams, and details of 

control measures. 

8. DESIGNATED CONTACT PERSON - Specify the person with whom the FAA will communicate if additional information is 

needed. This should be the person most knowledgeable about laser safety of this operation. However, the person could also be the

laser operation central contact that interfaces with the FAA. The Designated Contact Person should work for or represent the 

proponent listed in 1.(b).

9. STATEMENT OF ACCURACY - The person having the authority to bind the proponent must sign the form. 

10. WORKSHEET INSTRUCTIONS – See AC 70-1, Outdoor Laser Operation(s). 

11. PAPERWORK REDUCTION ACT STATEMENT -Through use of this AC, the FAA intends to maintain a high level

of safety between laser operations and aircraft operations. The FAA is requesting that laser operators submit information on a

voluntary basis using the forms listed in this AC. It will take the proponent approximately 10 hours to provide the necessary

information for the initial system analysis. The time should decrease with subsequent submissions for the use of the same laser system

by the same respondent. A person is not required to respond to an information collection request unless it displays a currently valid 

Office of Management and Budget (OMB) number. The OMB control number assigned this request is 2120-0662. 

Page 4 
12/30/04 AC 70-1 

 Appendix 1 

 Page 5 
AC 70-1 12/30/04 

Appendix 1 

INSTRUCTIONS FOR COMPLETING LASER CONFIGURATION WORKSHEET 

A single outdoor operation may have a number of lasers or “laser configurations” – power settings, wavelength, pulse modes, 

divergence, etc. In section 7.(a), of the Notice of Proposed Outdoor Laser Operations form, enter the number of different laser 

configurations for the outdoor operation. Then, complete one Laser Configuration Worksheet (page 3) for each different 

configuration. 

Through use of the AC the FAA intends to maintain a high level of safety between laser operations and aircraft operations without 

regulating certain entities that were not previously regulated. The FAA is requesting that laser operators submit information on a 

voluntary basis by using the forms listed and enclosed in this AC. 

It will take the proponent approximately 10 hours to provide the necessary information for the initial system analysis. The time

should decrease with subsequent submissions based on use of the same laser system per respondent per request. A person is not

required to respond to an information collection request unless it displays a currently valid Office of Management and Budget 

(OMB) control number. The OMB control number assigned to this request is 2121-0662. 

Data sources: This form requires calculations based on data concerning the laser beam’s characteristics. The data can be obtained 

from direct measurement, manufacturer specifications, or specialized instruments. Also, data may be derived by making reasonable,

conservative assumptions (e.g., that a certain value makes the beam more hazardous than it would be in reality). All data should err

on the side of safety. In borderline situations where data accuracy is crucial to compliance, provide additional information on 

measurement techniques, data sources, and assumptions. 

Alternative analysis: This form and accompanying tables must cover a wide variety of laser configurations. They are necessarily

simplified, and they make conservative assumptions. Some laser configurations may warrant a more complex analysis. Any such 

alternative analysis should be based on the American National Standards Institute (ANSI) Z136 series of standards or other

established methods. Both the methods and the calculations must be documented. 

1. CONFIGURATION INFORMATION – In 1.(a), enter the number of the specific configuration and the total number

of configurations. In 1.(b), enter the name of the event or facility. In 1.(c), enter the date the worksheet is prepared or 

sent to the FAA. In 1.(d), describe the beam projecting or directing system. Include a description of the site layout.

Attach additional sheets if more space is required.

2. GEOGRAPHIC LOCATION – In 2.(a), enter the elevation of the site in feet above Mean Sea Level (MSL). In 2.(b), 

enter the height of the laser above the site elevation. This value should reflect the total height including any tall structure 

or building on which the laser may be located. In 2.(c), enter the total height of the laser above MSL (site elevation + 

height above site elevation). For aircraft or spacecraft operations, attach additional information on the flight locations 

and altitudes. In 2.(d) and (e), enter the latitude and longitude in degrees, minutes and seconds. Some maps or devices

may give this information in “Degrees Decimal” form; convert this value into degrees, minutes, and seconds. In 2.(f),

enter the method used to determine the latitude and longitude. In 2.(g), enter the horizontal datum used to determine the 

latitude and longitude. In 2.(h), enter the vertical datum used to determine the site elevation.

3. BEAM CHARACTERISTICS AND CALCULATIONS - Determine the mode of operation for this configuration: single 

pulse, continuous wave, or repetitively pulsed. Check the appropriate column and fill out only the Beam Characteristics, MPE 

Calculations, and Visual Effect Calculations applicable to that column. 

Laser Type - Enter the lasing medium, for example, “Argon,” “Nd-YAG,” “Copper-vapor," “CO2,” etc.

Beam Diameter and Divergence - Provide the diameter using the 1/e peak-irradiance points; be sure the diameter is 

entered in centimeters, not millimeters. The divergence is the full angle given at the 1/e points. If you know the diameter or 

divergence measured at the 1/e

2

 points instead, multiply by 0.707 to convert to 1/e diameter or divergence. 

NOTE - Diameter and divergence measurements can be complex; if necessary, use conservative (larger diameter/smaller

divergence) simplifications. 

Wavelength - If the laser emits a single wavelength, enter this. If the laser emits multiple wavelengths, each wavelength 

should be analyzed separately to find the MPEs and NOHDs. There may be one wavelength that is most hazardous (e.g., MPE

the smallest, and NOHD the largest) so that subsequent calculations can make a simplifying, conservative assumption by

ignoring the less-hazardous wavelengths. For visible multiple-wavelength lasers, a simplifying, conservative assumption can

be made when performing Visual Effect Calculations: that the entire beam has the same wavelength as the most visible 

wavelength (largest Visual Correction Factor). In all cases of multiple-wavelength lasers, you must document your methods 

and calculations. If you do not analyze all wavelengths in full, then you must explicitly state your simplifying, conservative

assumptions.

Page 6 
12/30/04 AC 70-1 

 Appendix 1 

Repetitively pulsed vs. scanning- “Repetitively pulsed” refers to lasers that naturally emit repetitive pulses, such as 

Q-switched lasers. The form and tables are not intended for analyzing pulses due to scanning the beam over a viewer or aircraft (examples: 

graphics or beam patterns used in laser displays; scanned patterns used for LIDAR). Pulses resulting from scanning are often extremely

variable in pulse width and duration. Therefore, for a conservative analysis, assume the beam is static (non-scanned). Should you rely on 

scanning to be in compliance, you must: 1) provide a more comprehensive analysis, documenting your methods and calculations, and 2) 

document and use scan-failure protection devices. 

(a) MAXIMUM PERMISSIBLE EXPOSURE (MPE) CALCULATIONS - Provide the Maximum Permissible Exposure 

(MPE) calculation results in the applicable block. For convenience, a simplified, conservative method is provided in Tables 

1-4 of this document. If you require less conservative levels, use the American National Standards Institute (ANSI) Z136 

series of standards or other established methods. Both the methods and calculations must be documented.

 Single Pulse - Use Table 1 for lasers that produce a single pulse of energy with a pulse width < 0.25 seconds or a pulse 

repetition frequency < 1 Hz. Fill in the “MPE per pulse” block in the Single Pulse column. 

 Continuous Wave (cw) - A laser that produces a continuous (non-pulsed) output for a period > 0.25 seconds is 

regarded as a cw laser. Use Table 2 to find the MPE. Fill in the “MPE” block in the Continuous Wave column. 

 Repetitively Pulsed - Lasers that produce recurring pulses of energy at a frequency of 1 Hz or faster are considered to

be repetitively pulsed. These can produce an additional hazard above that of a single pulse or continuous wave laser. The 

MPE is adjusted for repetitively pulsed lasers based on its pulse repetition frequency and is designated as MPEPRF. The 

MPEPRF can be determined using either the per-pulse energy or the average power. This document provides a simplified

method for calculating the MPEPRF for average power with wavelengths in the visible and infrared region. (ANSI Z136 series 

can provide a less conservative value in some cases.) Although designated MPEPRF, the values should be placed in either the 

“MPE” or “MPE per pulse” blocks of the repetitively pulsed column. Following are the simplified methods for determining

the MPEPRF for: 

(1) Ultraviolet wavelengths: Reference the American National Standards Institute ANSI Z136 series. 

(2) Visible wavelengths: Use Table 3 to determine the MPEPRF. Table 3 results have already applied the correction factor 

to the cw MPE. Fill in the “MPE” block in the Repetitively Pulsed column. 

(3) Infrared wavelengths: 

Use Table 2 to find the cw MPE.

Use Table 4 to find the infrared pulse repetition correction factor.

Multiply the cw MPE times the infrared pulse repetition correction factor to give the MPEPRF. Fill in the “MPE” block 

in the Repetitively Pulsed column. 

NOTE - For Repetitively Pulsed lasers. The simplified methods of Tables 2-4 use the Average Power to determine the MPE in

W/cm2

. It is possible with other methods to use the Pulse Energy to determine the MPE per pulse in J/cm2. Only one of the two 

MPEs is required. 

(b) VISUAL EFFECT CALCULATIONS - If the laser has no wavelengths in the visible range (400-700 nm), enter “N/A (nonvisible laser)” in these blocks and go to the next section. For visible lasers, the FAA is concerned about beams that are eye-safe 

(below the MPE) but are bright enough to distract aircrews. The FAA has therefore established “Sensitive,” “Critical” and

“Laser-Free” areas where aircraft should not be exposed to light above 100μW/cm2

, 5μW/cm2, and 50nW/cm2 respectively.

Because apparent brightness varies with wavelength – green is more visible than red or blue – a visual effect correction factor can 

be applied if desired. This has the effect of allowing more power for red and blue beams than for green beams. For any visible 

laser, you must submit Visual Effect Calculations:

First, determine the Pre-Corrected Power. 

(1) Single Pulse - Multiply the Pulse Energy (J) by 4, and enter in the form. 

NOTE - This technique averages the pulse’s energy over the 0.25 sec maximum pulse duration, and is a conservative 

approximation of the visual effect of a pulse. If you use less conservative calculations, you must document your methods and 

calculations. 

(2) Continuous Wave - Use the Average Power (W) block already entered on the form. 

(3) Repetitively Pulsed - If you entered the Average Power (W) on the form, use that value. If you entered the Pulse Energy (J) 

on the form, multiply that value times the Pulse Repetition Frequency (Hz) to determine the average power. 

 Page 7 
AC 70-1 12/30/04 

Appendix 1 

Next, decide on how precise you want to be: 

For the simplest, most conservative analysis - Assume no correction factor at all, enter “1.0 (assumed)” for the Visual

Correction Factor, and the Pre-Corrected Power found above for the Visually Corrected Power. 

For a single-wavelength beam use Table 5 to find the Visual Correction Factor. Multiply this by the Pre-Corrected Power to 

find the Visually Corrected Power. 

For a beam with multiple wavelengths, choose one method: 

a. Make a simplifying, conservative assumption. Use Table 5 to determine which wavelength has the largest Visual Correction 

Factor (is the most visible). Multiply this Visual Correction Factor by the Pre-Corrected Power of the laser (all wavelengths) to 

find the Visually Corrected Power. NOTE - You must attach data and calculations showing how you arrived at the 

Visually Corrected Power. 

b. Analyze each wavelength separately, then sum them. First, determine the Pre-Corrected Power for each wavelength. Next,

use Table 5 to find the Visual Correction Factor for each wavelength. Multiply each wavelength’s Pre-Corrected Power by its 

Visual Correction Factor, to find the Visually Corrected Power (VCP) for that wavelength. Add all the VCPs together to

determine the total VCP. Enter the total VCP in the “Visually Corrected Power” block of the form. NOTE – You must attach 

data and calculations showing how you arrived at the Visually Corrected Power.

4. BEAM DIRECTION(S) – Enter the maximum and minimum elevation angles. Also, provide the pointing directions and 

elevation angles (minimum and maximum) of the beam projections for this configuration only:

If the beam is moved horizontally during the operation, enter the movement range under “Azimuth.” For example, “20° to 50°.” 

Make sure you give the range going clockwise, otherwise your data will be interpreted as directing the beam everywhere but

where you intend. Specify if azimuth is in true or magnetic readings. Provide the magnetic variation for the location if this is 

known (this must be done if you mark the “Magnetic” check box or if you are using a compass as part of your control 

measures). 

For some configurations, additional information concerning the beam direction may be needed. For example, lasers that are 

very widely separated at the Geographic Location listed on page 3, or a laser used on an aircraft or spacecraft which is moving

and/or shoots downward. 

5. CALCULATED DISTANCES (From above data) - There are four distances that are important in evaluating the safety

of outdoor operations. Brief definitions of these distances are as follows: 

Nominal Ocular Hazard Distance - The beam is an eye hazard (is above the MPE), from the laser source to this distance. 

Sensitive Zone Exposure Distance - The beam is bright enough to cause temporary vision impairment, from the source to

this distance. Beyond this distance, the beam is 100μW/cm2 or less. 

Critical Zone Exposure Distance - The beam is bright enough to cause a distraction interfering with critical task 

performance, from the source to this distance. Beyond this distance, the beam is 5 μW/cm2

 or less. 

“Laser-Free” Exposure Distance - Beyond this distance, the beam is 50 nW/cm2 or less – dim enough that it is not expected 

to cause a distraction.

Visible/non-visible determination - Determine whether one or more of the laser wavelengths are visible (in the range 400-

700 nm). If the laser is outside the visible range, enter “N/A (non-visible laser)” in all SZED, CZED, and LFED blocks. If 

the laser is visible, then perform the SZED, CZED, and LFED calculations. 

IMPORTANT - For some visible pulsed lasers, the SZED, CZED, and LFED may be calculated to be less (shorter distance) 

than the NOHD. If this is the case, for safety reasons do not enter the distance numbers in the applicable block. Instead, you

must enter that the distance is “Less than NOHD.” This is because in this case, the NOHD (eye-damage distance) would be the 

most important for calculating safety distances and airspace to be protected.

NOHD Slant Range – To determine the Nominal Ocular Hazard Distance slant range (SR) in feet, use Equation 6.1 for Single

Pulse or Repetitively Pulsed (if you calculated the Pulse Energy and MPE per pulse). Use Equation 6.2 for Continuous Wave or 

Repetitively Pulsed (if you calculated the Average Power and MPE). 

Page 8 
12/30/04 AC 70-1 

 Appendix 1 

INSTRUCTIONS FOR COMPLETING 

LASER CONFIGURATION WORKSHEET (Continued) 

Equation 6.1 

MPE H

32.8 1.27 Q SR × = ×

φ

Where: 

φ = Beam Divergence (mrad) 

Q = Pulse Energy (J)

MPEH = MPE per pulse in J/cm2 

32.8 = Conversion factor used to convert centimeters into feet, and radians into milliradians 

Equation 6.2 

MPEE

32.8 1.27 SR Φ = × ×

φ

Where: 

φ = Beam Divergence (mrad)

Φ = Average Power (W) 

MPEE = MPE in W/cm2 

32.8 = Conversion factor used to convert centimeters into feet, and radians into milliradians 

Example: A 40-watt cw laser has a beam divergence of 1.5 milliradians 

Given:

φ = 1.5 mrad 

Φ = 40 W

MPEE = 0.00254 (2.54 mW/cm2

, from Table 2)

Solve Equation 6.2: 

 21.87 21.87 141.42 3,093ft.

1.5

32.8 SR 20000

0.00254

1.27 40 = × = × = × = ×

Visual Effect Slant Ranges - If the laser has no wavelengths in the visible range (400-700 nm), enter “N/A (nonvisible laser)” in all blocks under “Visual Effect Distances.” For a visible laser, to calculate the slant range (SR)

in feet you must calculate equation 6.3 three times, using different values of EL (exposure level) each time. 

 Page 9 
AC 70-1 12/30/04 

Appendix 1 

INSTRUCTIONS FOR COMPLETING 

LASER CONFIGURATION WORKSHEET (Continued) 

Equation 6.3 

EL

32.8 1.27 VCP SR Φ = × ×

φ

Where: 

φ = Beam Divergence (mrad) 

ΦVCP = Visually Corrected Power (from form)

32.8 = Conversion factor used to convert centimeters into feet, and radians into milliradians 

EL = 1.0×10-8 W/cm2

 (100 μW/cm2) when calculating slant range for Sensitive Zone Exposure Distance (SZED)

EL = 5.0×10-7 W/cm2

 (5 μW/cm2) when calculating slant range for Critical Zone Exposure Distance (CZED) 

EL = 5.0×10-10 W/cm2

 (50 nW/cm2) when calculating slant range for Laser Free Exposure Distance (LFED)

Source: The equations above are derived from ANSI Z136.1 and have been re-expressed to a simpler form as 

follows: Beam divergence (φ) is entered in milliradians, making the first ANSI fraction 1,000/φ instead of 1/φ. The 

radical (square root) sign is used instead of raising to a power of 0.5. Under the radical, the expression 4/π is 

reduced to 1.27, while beam diameter (a2

) is not used since its contribution to the overall slant range distance is 

negligible. ANSI results are in cm; to convert to FAA’s desired feet, a conversion factor of 0.0328 is used

(1 cm = 0.0328 ft). There are now two numeric constants, 1,000 (from the milliradians fraction) and 0.0328, which 

are multiplied into a single constant, 32.8, to give results in feet. For results in cm, use “1,000” as the constant; for 

results in meters, use “10.” 

HORIZONTAL DISTANCE is the distance along the ground. For example, if a beam’s power drops to 100 μW

/cm2

 at 1,000 feet, and the beam is elevated at 30° above horizontal, the ground distance where 100 μW /cm2 is 

reached is 866 feet (1,000 x cos (30°)). Note that the horizontal distance uses the minimum elevation angle. 

Calculate the horizontal distance using the equation: 

HD = SR × (cos(Minimum Elevation Angle)) 

HD = Horizontal distance. The units are the same as for the Slant Range. If SR is in feet, then HD will also be in

feet. 

SR = Calculated Slant Range for NOHD, SZED, CZED, and LFED respectively.

Minimum Elevation Angle = Minimum elevation angle of laser beam as provided on form.

VERTICAL DISTANCE is the distance above the ground. In the example above, the beam’s power drops to

100 μW /cm2 at 500 feet (1000 x sin(30°)) above the ground. Note that the vertical distance uses the maximum

elevation angle. Calculate the vertical distance using the equation. 

VD= SR × (sin (Maximum Elevation Angle)). 

VD = Vertical distance. The units are the same as for the Slant Range(feet). 

SR = Calculated Slant Range for NOHD, SZED, CZED, and LFED respectively.

Maximum Elevation Angle = Maximum elevation angle of laser beam as provided on form.

6. CALCULATION METHOD - List the method by which the calculations were performed.

Page 10 
12/30/04 AC 70-1 

 Appendix 1 

TABLE 1. SINGLE PULSE SELECTED 

MAXIMUM PERMISSIBLE EXPOSURE (MPE) LIMITS 

Wavelength 

(nm) 

Exposure Duration 

(sec) 

MPE 

(J/cm2) 

Ultraviolet 

180 to 400 10-9 to 10 Reference American National

Institute Standard (ANSI) Z136 

series 

Visible 

400 to 700 <10-9

10-9 to 18×10-6

18×10-6 to 10 

0.25 

Reference ANSI Z136 series

0.5×10-6

1.8×t

0.75×10-3 

0.64×10-3

Infrared 

700 to 1050 <10-9

10-9 to 18×10-6

18×10-6 to 10 

0.25 

10 

Reference ANSI Z136 series

0.5×CA×10-6

1.8×CA×t

0.75×10-3 

0.64×CA×10-3 

10×CA×10-3

1050 to 1400 <10-9

10-9 to 50×10-6

50×10-6 to 10 

10 

Reference ANSI Z136 series

5.0×CC×10-6

9×CC×t

0.75×10-3

50×CC×10-3

1400 to 1500 <10-9

10-9 to 10-3

10-3 to 10 

10 

Reference ANSI Z136 series

0.1 

0.56×t

0.25

1.0 

1500 to 1800 <10-9

10-9 to 10 

10 

Reference ANSI Z136 series

1.0 

1.0 

1800 to 2600 <10-9

10-9 to 10-3

10-3 to 10 

10 

Reference ANSI Z136 series

0.1 

0.56×t

0.25

1.0 

2600 to 10,000 <10-9

10-9 to 10-7

10-7 to 10 

10 

Reference ANSI Z136 series

10×10-3

0.56×t

0.25

1.0 

To find CA:

For wavelength = 700 to 1050nm, CA = 100.002 (wavelength-700) 

Example 1 

Laser wavelength is 850nm; CA = 100.002(850-700) = 100.002*150 = 100.3 = 1.995

Example 2 

Laser wavelength is 933nm; CA = 100.002(933-700) = 100.002*233 = 100.466 = 2.924 

To find CC:

For wavelength = 1050 to 1150nm, CC = 1.0 

For wavelength = 1150 to 1200nm, CC = 100.018 (wavelength-1150)

For wavelength = 1200 to 1400nm, CC = 8.0 

Example 3 

Laser wavelength is 1175nm; Cc = 100.018(1175-1150) = 100.018*125 = 102.25 = 177.828

To find t: “t” is the pulse duration in seconds.

 Page 11 
AC 70-1 12/30/04 

Appendix 1 

TABLE 2. CW MODE MAXIMUM PERMISSIBLE EXPOSURE (MPE) LIMITS 

Values are for selected wavelengths for unintentional viewing. 

Wavelength

(nm) 

MPE 

(W/cm2) 

Ultraviolet 

180 to 400 Reference American National Standards Institute

ANSI Z136 series 

Visible 

400 to 700 2.54x10-3

Infrared 

700 to 1050 (100.002(wavelength - 700))(1.01x10-3) 

1050 to 1150 5x10-3

1150 to 1200 (10 0.018(wavelength-1150))(5 x10-3) 

1200 to 1400 4.0 x10-2

1400 to 10,000 0.1 

Example 1 

Laser wavelength is visible; MPE = 0.00254 W/cm2 

Example 2 

Laser wavelength is 850nm; MPE = (100.002(850 - 700))(1.01x10-3) = (100.002* 150)(0.0101) = (100.3) x 0.0101 = 

1.995 x 0.0101 = 0.02 W/cm2 

Example 3 

Laser wavelength is 1175nm; MPE = (10 0.018(1175-1150))(5 x10-3) = (10 0.018* 25)(0.005) = (10 0.45) x 0.005 =

2.818 x 0.005 = 0.01409 W/cm2 

“Unintentional viewing”: Exposure durations used for unintentional viewing of a cw exposure are 0.25 seconds

or shorter for visible lasers, and 10 seconds or shorter for infrared lasers. (For visible light, it is assumed that

within 0.25 seconds, the person will blink or will move to avoid the light. For infrared, it is assumed that the laser

will not stay in the same spot for more than 10 seconds, due to normal body movement.) 

Source: ANSI Z136.1 Table 5 for CW Exposure. 

Page 12 
12/30/04 AC 70-1 

 Appendix 1 

TABLE 3. MAXIMUM PERMISSIBLE EXPOSURE – PULSE REPETITION 

FREQUENCY (MPEPRF) LIMITS FOR VISIBLE LASERS

For unintentional viewing of repetitively pulsed visible (400-700nm) laser light with pulse width between 1ns and 18μs. 

Pulse 

Repetition 

Frequency 

(Hz)

MPEPRF 

(W/cm2) 

Pulse 

Repetition 

Frequency 

(Hz)

MPEPRF 

(W/cm2) 

Pulse 

Repetition 

Frequency 

(Hz)

MPEPRF 

(W/cm2) 

1 7.07×10-7 30 9.06×10-6 5,000 4.20×10-4

2 1.19×10-6 40 1.12×10-5 10,000 7.07×10-4

3 1.61×10-6 50 1.33×10-5 15,000 9.58×10-4

4 2.00×10-6 75 1.80×10-5 20,000 1.19×10-3

5 2.36×10-6 100 2.24×10-5 25,000 1.41×10-3

6 2.71×10-6 150 3.03×10-5 30,000 1.61×10-3

7 3.04×10-6 200 3.76×10-5 40,000 2.00×10-3

8 3.36×10-6 250 4.45×10-5 50,000 2.36×10-3

9 3.67×10-6 500 7.48×10-5 55,000 2.54×10-3

10 3.98×10-6 1000 1.26×10-4 100,000 2.54×10-3

15 5.39×10-6 1500 1.70×10-4

20 6.69×10-6 2000 2.11×10-4

25 7.91×10-6 2500 2.50×10-4

If the laser’s pulse repetition frequency falls between two table entries, use the more conservative (smaller) value of the 

two resulting MPEPRF values. 

NOTE: This table for MPEPRF is based on repetitively pulsed lasers with a pulse width between 1ns and 18μs. These 

MPEPRF numbers can be used to estimate larger pulse widths, and will provide a conservative (safer) result. 

Not intended for scanning analysis: This table is intended for lasers that naturally emit repetitive pulses, such as

Q-switched lasers. It is not intended for analyzing “scanned” pulses, caused by moving the beam quickly over a viewer 

or aircraft. (Examples: graphics or beam patterns used in laser displays, or scanned patterns used for atmospheric

analysis.) Pulses resulting from scanning are often extremely variable in pulse width and duration, and thus require a 

more stringent analysis. 

 Page 13 
AC 70-1 12/30/04 

Appendix 1 

TABLE 4. CORRECTION FACTORS (MPEPULSED / MPECW) 

FOR REPETITIVELY PULSED INFRARED LASERS

Use to define MPEPRF of repetitively pulsed infrared (700-1400nm) laser light with pulse width between 1ns and 18μs. 

Pulse Repetition 

Frequency 

(Hz)

Correction Factor

For wavelengths 

700 –1050 nm

Correction Factor

For wavelengths 

1050-1400 nm

1 2.8×10-4 5.5×10-4

5 9.4×10-4 1.8×10-3

10 1.6×10-3 3.1×10-3

15 2.1×10-3 4.2×10-3

20 2.6×10-3 5.2×10-3

25 3.1×10-3 6.2×10-3

50 5.3×10-3 1.0×10-2

75 7.1×10-3 1.4×10-2

100 9.0×10-3 1.7×10-2

150 1.2×10-2 2.4×10-2

200 1.5×10-2 2.9×10-2

250 1.8×10-2 3.5×10-2

500 3.0×10-2 5.9×10-2

1,000 5.0×10-2 1.0×10-1

2,000 8.0×10-2 1.7×10-1

3,000 1.1×10-1 2.3×10-1

4,000 1.4×10-1 2.8×10-1

5,000 1.7×10-1 3.3×10-1

10,000 2.8×10-1 5.6×10-1

15,000 3.8×10-1 7.5×10-1

20,000 4.7×10-1 9.3×10-1

21,000 4.8×10-1 9.7×10-1

22,000 5.0×10-1 1.00 * 

23,000 5.2×10-1 1.00 

24,000 5.4×10-1 1.00 

25,000 5.5×10-1 1.00 

30,000 6.3×10-1 1.00 

40,000 7.9×10-1 1.00 

50,000 9.3×10-1 1.00 

55,000 1.00 * 1.00

* The MPE for lasers which operate at a PRF greater (faster) than 55,000 Hz for wavelengths 700-1050nm (or 

22,000 Hz for wavelengths 1050-1400nm) is the same as for continuous wave lasers, so the correction factor is 1. 

To find the MPE for repetitively pulsed infrared lasers, multiply the CW Mode MPE by a correction factor from

this table. If the laser’s pulse repetition frequency falls between two table entries, use the more conservative 

(smaller) value of the two resulting correction factors. 

Example: A laser operating at a pulse repetition frequency (PRF) of 12,000 Hz emits infrared light at 850nm. First,

go to Table 2 and find the CW Mode MPE for the 850nm wavelength; this is 0.002 W/cm2 (see example 2 from

Table 2). Next, from the table above determine which of the right two columns should be used; in this case, the

column labeled “For wavelength 700-1050nm." The laser’s PRF of 12,000 Hz falls between the 10,000 and 15,000 

rows, so use the more conservative (smaller) value of the 10,000 Hz PRF: 2.8 x 10-1. The correction factor is thus 

0.28. Multiply this by the CW Mode MPE found from Table 2 to get a MPEPRF of 0.28 x 0.002 W/cm2

 = 0.00056 

W/cm2

 = 5.6 x 10-4 W/cm2. 

Page 14 
12/30/04 AC 70-1 

 Appendix 1 

TABLE 5. VISUAL CORRECTION FACTOR FOR VISIBLE LASERS

Use for visible lasers only (400-700 nm). 

Laser Wavelength 

(nm)

Visual Correction 

Factor 

(VCF) 

400 

410 

420 

430 

440 

450 

460 

470 

480 

490 

500 

510 

520 

530 

540 

550 

555 

560 

570 

580 

590 

600 

610 

620 

630 

640 

650 

660 

670 

680 

690 

700 

4.0 x 10-4

1.2 x 10-3

4.0 x 10-3

1.16 x 10-2

2.30 x 10-2

3.80 x 10-2

5.99 x 10-2

9.09 x 10-2

1.391 x 10-1

2.079 x 10-1

3.226 x 10-1

5.025 x 10-1

7.092 x 10-1

8.621 x 10-1

9.524 x 10-1

9.901 x 10-1

1.0 x 100

9.901 x 10-1

9.524 x 10-1

8.696 x 10-1

7.576 x 10-1

6.329 x 10-1

5.025 x 10-1

3.817 x 10-1

2.653 x 10-1

1.751 x 10-1

1.070 x 10-1

6.10 x 10-2

3.21 x 10-2

1.70 x 10-2

8.2 x 10-3

4.1 x 10-3

(VCF=1) 

To find the Visually Corrected Power (VCP) for a specified wavelength, multiply the Visual Correction Factor 

(VCF) for the wavelength (from the table above) by the Average Power. If the laser’s wavelength falls between 

two table entries, use the more conservative (larger) value of the two resulting VCFs. 

Example 1: A frequency-doubled YAG laser emits 10 watts of 532nm continuous wave light. From the table, 532

is between 530 and 540; use the more conservative (larger) Visual Correction Factor of 540nm: 9.524 x 10-1. 

Multiply the VCF of 0.9524 by the Average Power of 10 watts, to obtain the Visually Corrected Power of 9.524 

watts. 

Example 2: An 18-watt argon laser emits 10 watts of 514nm light, and 8 watts at 488nm light, both continuous 

wave. Calculate each wavelength separately, and then add the resulting Visually Corrected Powers together. 

 Page 15 
AC 70-1 12/30/04 

Appendix 1 

TABLE 5. VISUAL CORRECTION FACTOR FOR VISIBLE LASERS (Continued) 

10 watts at 514nm: From the table, 514 is between 510 and 520, use the more conservative (larger) VCF of 520nm:

7.092 x 10-1. Multiply the VCF of 0.7092 by the Average Power of 10 watts to obtain the Visually Corrected Power of

7.092 watts. 

8 watts at 488nm: From the table, 488 is between 480 and 490; use the more conservative (larger) VCF of 490nm:

2.079 x 10-1. Multiply the VCF of 0.2079 by the Average Power of 8 watts, to obtain the Visually Corrected Power of

1.6632 watts. 

Finally, add the two VCPs together: 7.092 + 1.6632 = 8.7552. The 18-watt laser in this example has a Visually

Corrected Power of only 8.7552 watts. 

Note: Example 1 is the 10-watt YAG which appears brighter to the eye (9.5 WVCP) than an 18-watt argon (8.8 WVCP).

Source: The Visual Correction Factor used in this table (CF) is the CIE normalized efficiency photopic visual 

function curve for a standard observer. The luminance (lm•cm-

2) is the measured irradiance multiplied by CF

and 683. The effective irradiance is the actual (measured) irradiance multiplied by CF. The effective irradiance 

(W⋅cm-2) multiplied by 683 lm⋅W-1 is the illuminance (lm⋅cm-2). The term “Visually Corrected Power” used in this

document is the same as “effective irradiance.” 

Page 16 
12/30/04 AC 70-1 

 Appendix 1 

LASER FREE ZONE 

 Page 17 
AC 70-1 12/30/04 

Appendix 1 

AIRSPACE FLIGHT ZONES 

1. Laser Free Zone (LFZ): Airspace in the 

immediate proximity of the airport, up to and 

including 2,000 feet AGL, extending 2 nautical miles 

in all directions measured from the runway centerline. 

Additionally, the LFZ includes a 3nm extension,

2,500 feet each side of the extended runway

centerline, up to 2,000 feet AGL of each useable

runway surface. The level of laser light is restricted

to a level that should not cause any visual disruption. 

2. Critical Flight Zone (CFZ): Airspace within a 

10-nautical-mile (nm) radius of the Airport Reference 

Point (ARP), up to and including 10,000 feet AGL, 

where a level of laser light is restricted to avoid 

flashblindness or afterimage effects. 

3. Sensitive Flight Zone (SFZ): Airspace outside 

the Critical Flight Zone(s) that authorities (e.g., FAA, 

local departments of aviation, military, etc.) have 

identified that must be protected from flashblindness 

or afterimage effects. 

4. Normal Flight Zone (NFZ): Airspace not defined 

by the Laser Free, Critical, or Sensitive Flight Zones.

Page 18 
12/30/04 AC 70-1 

 Appendix 1 

Page 19 (and 20) 

12/30/04 AC 70-1 

 Appendix 2 

APPENDIX 2 

FEDERAL AVIATION ADMINISTRATION REGIONAL OFFICE ADDRESSES

ADDRESS

Attn: Manager, Operations Branch 

Alaskan Region, AAL-530 

222 West 7th Ave # 14

Anchorage, AK 99513-7587 

Attn: Manager, Airspace Branch 

Central Region, ACE-520 

901 Locust 

Kansas City, MO 64106 

Attn: Manager, Airspace Branch 

Eastern Region, AEA-520

1 Aviation Plaza 

Jamaica, NY 11434-4809

Attn: Manager, Airspace Branch 

Great Lakes Region, AGL-520

2300 East Devon Avenue

Des Plaines, IL 60018 

Attn: Manager, Airspace Branch 

New England Region, ANE-520 

12 New England Executive Park 

Burlington, MA 01803 

Attn: Manager, Airspace Branch 

Northwest Mountain Region, ANM-520

1601 Lind Avenue, S.W. 

Renton, WA 98055

Attn: Manager, Airspace Branch 

Southern Region, ASO-520 

P.O. Box 20636

Atlanta, GA 30320

Attn: Manager, Airspace Branch 

Southwest Region, ASW-520 

2601 Meacham Blvd. 

Fort Worth, TX 76137

Attn: Manager, Airspace Branch 

Western Pacific Region, AWP-520 

P.O. Box, 92007

Los Angeles, CA 90009

REGION/STATES/PHONES

ALASKA

AK 

(907) 271-5470

CENTRAL 

IA, NE, KS, MO

(816) 329-2520

EASTERN 

NY, WV, VA, MD, PA,

NJ, DE, WASH D.C. 

(718) 553-4530

GREAT LAKES 

OH, MI, IL, IN, 

MN, WI, ND, SD 

(847) 294-7477 

NEW ENGLAND 

RI, MA, ME, CT, VT, NH

(781) 238-7520 

NORTHWEST MOUNTAIN 

WA, OR, ID, MT, WY, UT, CO

(425) 227-2520 

SOUTHERN 

GA, AL, MS, FL, 

KY, TN, NC, SC

(404) 305-5491

SOUTHWEST 

TX, AR, OK, NM, LA 

(817) 222-5594

WESTERN PACIFIC 

CA, NV, AZ, HI 

(310) 725-6539

Page 1 (and 2)

12/30/04 AC 70-1 

 Appendix 3 

APPENDIX 3. GLOSSARY 

j) Laser – An acronym for light amplification by

stimulated emission of radiation. A laser is a device that 

produces an intense, directonal, coherent beam of visible or

invisible light..

a) Afterimage – A residual image left in the visual 

field after an exposure to a bright light. 

b) Center for Devices and Radiological Health

(CDRH) – An office of the FDA concerned with enforcing

compliance with the Federal requirements for laser

products including laser light shows.

k) Laser Manufacturer – A term that refers to persons 

who make laser products, including those who are engaged

in the business of design, assembly, or presentation of a 

laser light show. c) Demonstration – Any laser product designed or

intended for purposes of visual display of laser beams, for

artistic composition, entertainment, and /or advertising

display (see 21 CFR 1040.10(b) 13).

l) Laser Safety Officer (LSO) – One who has

authority to monitor and enforce the control of laser 

hazards and affect the knowledgeable evaluation and

control of laser hazards. d) Divergence – The increase in the diameter of the

laser beam with distance from the exit aperture based on

the full angle at the point where the irradiance (or radiant

exposure for pulsed lasers) is 1/e times the maximum

value. 

m) Laser Operator – A knowledgeable person present

during laser operation who has been given authority to

operate the laser system in compliance with applicable

safety standards, subject to recommendations of the LSO.

e) Flashblindness – Generally, a temporary visual 

interference effect that persists after the source of

illumination has ceased. 

n) Laser Safety Observer – One who is responsible

for monitoring the safe operation of a laser and can effect 

termination of the laser emission in the event an unsafe

condition is imminent. f) Flight Safe Level – An estimate of the maximum

exposure of radiant light energy emission (irradiance value)

allowed to illuminate an aircraft within specific flight

zones. 

o) Local Laser Working Group (LLWG) – A group 

that, when necessary, is convened to assist the regional air 

traffic division in evaluating the potential effect of laser

emissions on aircraft operators in the local vicinity of the 

proposed laser activity.

g) Flight Zones – Airspace areas specifically intended 

to mitigate the potential hazardous effect of laser 

emissions. These areas may not be contiguous or 

concentric as the other zones. There are several types of

flight zones: 

p) Maximum Permissible Exposure (MPE) – The level

of laser radiation to which a person may be exposed without 

hazardous effect or adverse biological change in the eye or 

skin. In general, MPE is expressed as mW/cm2 or mJ/cm2. 1. Laser Free Zone (LFZ) – Airspace zone where the

level of laser light is restricted to a level that should not

cause any visual disruption. q) Milliradian (mrad) – A measure of angle used for 

beam divergence. 2. Critical Flight Zone (CFZ) – Airspace zone where a 

level of laser light is restricted to avoid flashblindness or

afterimage effects. 

r) Nominal Ocular Hazard Distance (NOHD) – The 

maximum distance from the laser system beyond which the 

laser-beam irradiance does not exceed the MPE for that 

laser. 3. Sensitive Flight Zone (SFZ) – Airspace zone

outside the critical flight zones that authorities (e.g., FAA, 

local departments of aviation, military) have identified that 

must be protected from the potential effects of laser 

emissions. 

s) Radiant Exposure – A means of expressing the

intensity of the beam. This is generally expressed as 

J/cm2. 

4. Normal Flight Zones (NFZ) – Airspace zone not t) Reflected Beams – 

defined by the Laser Free, Critical, or Sensitive Flight 

Zones. 1. Diffuse - The component of a reflection from a surface

that is incapable of producing a virtual image such as is 

commonly found with flat finish paints or rough 

surfaces. A diffuse surface will reflect the laser beam in

many directions. 

h) Irradiance – Irradiance is a means of expressing the

intensity of the beam. Generally, the power per unit area

expressed in watts per centimeter squared.

i) Joule (J) – The International system unit of energy,

equal to the work done when a current of one ampere is 

passed through a resistance of one ohm for one second.

2. Specular - A mirror-like reflection that usually

maintains the directional characteristics of the beam. 

 Page 1 
AC 70-1 12/30/04 

Appendix 3 

u) Slant Range – The distance directly along the beam

(e.g., “slant range” does not vary depending on beam

elevation angle). 

v) Terminated Beam - A laser beam that enters 

navigable airspace that is confined by an object that blocks 

the beam or prohibits the continuation of the beam at levels 

above the applicable flight safe level. 

w) Unterminated Beam - A laser beam that is directed 

or reflected into navigable airspace. The proponent should 

provide sufficient evidence to the FDA and the FAA that

users of the NAS are not affected. 

x) Variance - Permission from FDA for a laser 

manufacturer and/or operator to deviate from one or more 

requirements of 21 CFR 1040 when alternate steps are 

taken to provide equivalent level of safety. 

y) Watts - A unit of measurement associated with

power output. Often the wattage of a laser system is

prefixed with milli (mW), micro (μW), and nano (nW). 

One watt is one joule per second. 

Page 2