Section 2. Evaluating Aeronautical Effect

1. SERVICE CENTER COORDINATION

The designated Service Center (SC) Point of Contact (POC) normally serves as the single agency contact with the laser proponent. The SC POC is responsible for:

1. Reviewing the information and data submitted by a proponent for an outdoor laser proposal for completeness.

1. Coordinating with all parties affected by the proposal (for example, state or local aviation authorities, DoD, airport operators, etc.).
2. Air Traffic analysis, including any IFR and VFR flight operations that may be affected by the proposal.

1. Determining on a case-by-case basis that aspects of certain flight operations require consultation and joint analysis by the ATO and AFS to ensure safety during a proposed laser operation. The SC POC will contact the RNGB designee for assistance in those situations.
2. The Flight Standards safety analysis will be conducted by the designated RNGB AWO. AFS analysis will include reviewing potential effects on flight crews operating under IFR or VFR. Special attention will be afforded examining unique local VFR operations and special instrument procedures. The safety analysis provided to the SC POC will state any AFS objections or concerns and indicate whether mitigations, if proposed, appear adequate. The SC POC is responsible for evaluating all input from the affected Air Traffic Facilities/RNGB and resolving conflicting concerns or issues.

1. AERONAUTICAL REVIEW

1. 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.

1. A laser-free zone is limited to 50nW/cm² or less.
2. A critical flight zone is limited to 5℞W/cm² or less.
3. A sensitive flight zone is limited to 100℞W/cm² or less.
4. 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.

1. Consult FDA/CDRH personnel for technical advice. (for example, regarding repetitively pulsed laser calculations)
2. Scientific/research lasers in accordance with 21 CFR § 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.

1. LOCAL LASER WORKING GROUP (LLWG)

When necessary, the Service Center OSG may convene and chair an LLWG to assist in evaluating proposed laser operation.

1. The Service Center OSG will forward all available information on a proposed outdoor laser operation to the appropriate parties of the LLWG.
2. Participants may include, but are not limited to, representatives from the ARTCC, TRACON, ATCTs, Flight Standards Division designee (either the assigned AWO or a designated field office representative), airport management, airspace users, city/county/state officials, other government agencies, military representatives, qualified subject experts, and laser manufacturers, etc.
3. The LLWG will identify and attempt to resolve issues regarding local laser operations.

1. PROTECTION DISTANCE CALCULATIONS

1. 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.
2. 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.
3. 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.
4. 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.
5. Do not reduce calculated distances for correction factor techniques unless validated by FDA/CDRH.
6. 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.

1. CONTROL MEASURES

Physical, procedural, and automated control measures, or some combination of the three, 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, or any additional restrictions established as a provision, condition, or limitation of a determination.

1. Physical beam stops at the system location or at a distance may be used to prevent laser light from being directed into protected zones.
2. The beam divergence, azimuth, elevation, and output power may be adjusted to meet appropriate irradiance levels.
3. 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.
4. 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.
5. 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.

1. Any laser operator planning to use an automated system designed to detect aircraft and automatically terminate the beam, redirect the beam, or shutter the system, must provide documentation to the Service Center OSG that validates the system's compliance with SAE International Aerospace Standard (AS) 6029, Performance Criteria for Laser Control Measures Used for Aviation Safety, before the use of the device may be accepted as a control measure and eliminate the need for safety observers.

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

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

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)