U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION

ORDER
JO 7400.2K
Effective Date:
April 3, 2014
 
     

Subject:  Procedures for Handling Airspace Matters
This Basic includes Change 1 effective 7/24/14.

 

Section 2. Evaluating Aeronautical Effect

29-2-1. AERONAUTICAL REVIEW

a. At a minimum the following items must be studied as part of any aeronautical review:

1. Location of the proposed laser operation.

2. Aircraft operations affected by the proposed operation.

3. Air traffic flows in the proposed area of the operation.

4. An analysis of adverse effect conducted by the ATC facility having control over the affected airspace.

5. A safety analysis conducted by the Flight Standards Division regarding the effects on flight crews.

6. For visible laser systems, plot the LFZ, CFZ, and SFZ (if applicable) for all potentially affected airports and evaluate any control measures, which may mitigate any adverse effect.

7. The effective irradiance levels listed below must not be exceeded in the corresponding zones.

(a) A laser-free zone is limited to 50nW/cm2 or less.

(b) A critical flight zone is limited to 5mW/cm2 or less.

(c) A sensitive flight zone is limited to 100mW/cm2 or less.

(d) A normal flight zone, as well as the above zones, is limited to the MPE or less.

EXCEPTION-
The LFZ, CFZ, and SFZ need only be considered for visible laser systems. Further, when control measures (e.g., safety observers) mitigate all hazards or other issues raised by the aeronautical review, irradiance levels may exceed the above levels.

b. Consult FDA/CDRH personnel for technical advice. (e.g., regarding repetitively pulsed laser calculations)

c. Scientific/research lasers in accordance with 21 CFR Section 1010.5 may be exempt from Title 49 and, in addition, may not be able to comply with the above procedures. Regardless of whether or not a proponent is exempt from the provisions, a proposal is still reviewed using the above procedures.

29-2-2. LOCAL LASER WORKING GROUP (LLWG)

When necessary, the service area office may convene a LLWG to assist in evaluating proposed laser operation.

a. The service area office must forward information on a proposed outdoor laser operation to the local air traffic facility.

b. The local air traffic facility must act as the focal point for the LLWG. Other participants may include, but not limited to, representatives from the ARTCC, ATCTs, airport management, airspace users, city/county/state officials, other government agencies, military representatives, qualified subject experts, laser manufacturers, etc.

c. The LLWG must resolve issues regarding local laser operations and forward recommendations to the service area office as soon as practicable.

29-2-3. PROTECTION DISTANCE CALCULATIONS

a. The laser system power range table (TBL 29-2-1) provides the applicable protection distances along the axis of the laser beam with a 1mrad divergence. This table must not be used to determine the protection distances for repetitively pulsed (RP) lasers. Proponents are required to resolve RP laser system calculations with the FDA or laser manufacture before submitting a completed Laser Configuration Worksheet to the FAA.

b. TBL 29-2-2 lists sine and cosine values to be used in determining the vertical and horizontal distances to be protected from the laser source. The distances obtained from TBL 29-2-1 are multiplied by these values to determine the appropriate vertical and horizontal distances to be protected based on the minimum and maximum vertical angles. Differences in site/ground elevations should be considered.

c. The vertical component of the protection distance may be determined by multiplying the laser distance from TBL 29-2-1 by the sine of the maximum elevation angle of the laser beam from TBL 29-2-2. For example, vertical component = protection distance x sine of the maximum elevation angle.

d. The horizontal component of the protection distance may be determined by multiplying the laser distance from TBL 29-2-1 by the cosine of the minimum elevation angle of the laser beam from TBL 29-2-2. For example, horizontal component = protection distance x cosine of the minimum elevation angle.

e. Do not reduce calculated distances for correction factor techniques unless validated by FDA/CDRH.

f. All distances must be rounded up to the next 100-foot increment. See example problems 1, 2, and 3 that follow the Vertical and Horizontal Component Table, TBL 29-2-2.

29-2-4. CONTROL MEASURES

Physical, procedural, and automated control measures may be used to ensure that aircraft will not be exposed to levels of illumination greater than the respective maximum irradiance levels established for the various protected zones.

a. Physical beam stops at the system location or at a distance may be used to prevent laser light from being directed into protected zones.

b. The beam divergence, azimuth, elevation, and output power may be adjusted to meet appropriate irradiance levels.

c. Beam direction should be specified by giving bearing in the azimuth scale 0 - 360 degrees and elevation in degrees ranging from 0 - 90 degrees, where zero degrees is horizontal and +90 degrees is vertical. Bearings must be given in both true and magnetic north.

d. Manual operation of a shutter or beam termination system can be used in conjunction with safety observers. Observers must have an adequate view of the airspace surrounding the beam's paths to a distance appropriate to the affected airspace.

e. Scanning of a laser system that is designed to automatically shift the direction of the laser beam can be used. However, scanning safeguards must be found to be acceptable by the FDA and the FAA. The FDA recommendation must be included in the proposal to the FAA.

NOTE-
Scanning may reduce the level of illumination; however, it may also increase the potential frequency of an illumination.

f. Any automated system designed to detect aircraft and automatically terminate the beam, redirect the beam, or shutter the system, must be reviewed and found to be acceptable by the FAA before the use of the device may be accepted as a control measure.

TBL 29-2-1
LASER SYSTEM POWER RANGE TABLE
CW Laser Beam Divergence: 1 Milliradian
* NOT TO BE USED WITH RP SYSTEMS

W/cm^2 --->

2.60E-03

1.00E-04

5.00E-06

5.00E-08

 

CW Laser Power (W)

Nominal Ocular Hazard Distance NOHD (ft)

Sensitive Zone Exposure Distance SZED (ft)

Critical Zone Exposure Distance CZED (ft)

Laser-Free Zone Exposure Distance LZED (ft)

LZED (nm)

1

726

3701

16553

165527

27

2

1026

5234

23409

234090

39

3

1257

6411

28670

286700

47

4

1452

7403

33105

331053

54

5

1623

8276

37013

370129

61

6

1778

9066

40546

405456

67

7

1920

9793

43794

437942

72

8

2053

10469

46818

468180

77

9

2178

11104

49658

496580

82

10

2295

11704

52344

523441

86

11

2407

12276

54899

548990

90

12

2514

12822

57340

573401

94

13

2617

13345

59681

596815

98

14

2716

13849

61934

619344

102

15

2811

14335

64108

641082

106

16

2903

14805

66211

662106

109

17

2993

15261

68248

682484

112

18

3080

15703

70227

702270

116

19

3164

16134

72151

721514

119

20

3246

16553

74026

740257

122

25

3629

18506

82763

827633

136

30

3976

20273

90663

906626

149

35

4294

21897

97927

979268

161

40

4591

23409

104688

1046882

172

45

4869

24829

111039

1110386

183

50

5133

26172

117045

1170450

193

55

5383

27449

122758

1227578

202

60

5623

28670

128216

1282163

211

65

5852

29841

133452

1334518

220

70

6073

30967

138489

1384895

228

75

6286

32054

143350

1433502

236

80

6492

33105

148051

1480515

244

85

6692

34124

152608

1526079

251

90

6886

35113

157032

1570323

258

95

7075

36076

161335

1613353

266

100

7259

37013

165527

1655266

272

105

7438

37927

169614

1696143

279

110

7613

38819

173606

1736057

286

115

7784

39692

177507

1775075

292

120

7952

40546

181325

1813253

298

125

8116

41382

185064

1850643

305

130

8276

42201

188729

1887293

311

135

8434

43005

192324

1923245

317

140

8589

43794

195854

1958537

322

145

8741

44569

199320

1993204

328

150

8890

45331

202728

2027278

334

155

9037

46081

206079

2060789

339

160

9182

46818

209376

2093764

345

* The FDA may be contacted to validate data for repetitively pulsed lasers.

NOTE-
[1] To determine the NOHD for lasers having divergence values other than 1.0 mrad use the formula - NOHD @ 1.0 mrad mrad (actual divergence) = NOHD.

EXAMPLE-
Power 40W, Divergence 7 mrad
NOHD 40W @ 1.0 mrad = 4,591
4,591 7 = 656 NOHD. Rounded up to nearest hundred feet = 700 feet.
(A beam divergence of .7 would make this calculation 7,000 feet)

* The proponent validates repetitive pulsed information with the FDA and submits a completed laser configuration worksheet.

TBL 29-2-2
VERTICAL AND HORIZONTAL COMPONENTS

VERTICAL COMPONENT

Maximum
Elevation Angle

Sine
(vertical component
multiplier)

90

1.0000

85

.9962

80

.9848

75

.9659

70

.9397

65

.9063

60

.8660

55

.8192

50

.7660

45

.7071

40

.6428

35

.5736

30

.5000

25

.4226

20

.3420

15

.2588

10

.1737

5

.0872

0

.0000

HORIZONTAL COMPONENT

Minimum
Elevation Angle

Cosine
(horizontal component
multiplier)

0

1.0000

5

.9962

10

.9848

15

.9659

20

.9397

25

.9063

30

.8660

35

.8192

40

.7660

45

.7071

50

.6428

55

.5736

60

.5000

65

.4226

70

.3420

75

.2588

80

.1737

85

.0872

90

.0000

 

LASER PROBLEM SOLUTIONS

EXAMPLE PROBLEM 1:
Laser output power = 15 watts
Laser beam divergence = 1.0 mrad
Find: Laser protection distances:
1. Find TBL 29-2-1 at 15 watts in the Laser Output Power column.
2. Proceed horizontally and read: NOHD of
2,811 feet, CFZ of 64,108 feet, SFZ 14,335 feet.
Answer: (with rounded up distances): NOHD
2,900 feet, CFZ 64,200 feet, SFZ 14,400 feet.

EXAMPLE PROBLEM 2
Laser output = 18 watts
Laser beam divergence = 1.0 mrad
Maximum elevation angle 60
Minimum elevation angle 20
Find:Vertical and horizontal distances to be protected:
1. Laser distance (from TBL 29-2-1) = 3,080 feet.
2. Sine of 60 maximum elevation angle (from
TBL 29-2-2) = 0.8660.
3. Find altitude by multiplying 3,080 feet
by 0.8660 = 2,667 feet.
4. Cosine of 20 minimum elevation angle (from TBL 29-2-2) = 0.9397
5. Find horizontal distance by multiplying 3,080 feet by 0.9397 = 2,894 feet.
Answer: Minimum required protected airspace
is 2,700 feet vertically and 2,900 feet horizontally from the laser source.

EXAMPLE PROBLEM 3
Power = 25 watts
Laser NOHD at 1 mrad = 3,629 feet.
Beam Divergence = .7 mrad
Find: Actual NOHD
1. Find actual NOHD by dividing the NOHD at 1 mrad divergence (3,629 feet) by actual divergence
(.7 mrad).
2. 3629 feet. .7 = 5184 feet.
Answer: NOHD 5,200 feet (rounded up)
 

 

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