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Attachment 1

Operating Limits

The FAA has issued grants of exemption in circumstances similar in all material respects to those 

presented in ASEC exemption #11509, where the FAA found that the enhanced safety achieved using an 

unmanned aircraft (UA) with the specifications described by the petitioner and carrying no passengers or 

crew, rather than a manned aircraft of significantly greater proportions, carrying crew in addition to 

flammable fuel, gave the FAA good cause to find that the UAS operations enabled by these exemptions is 

in the public interest.

ASEC proposes additional limitations for at least an equivalent, or even higher level of safety to 

operations under the current regulatory structure. The following proposed operations represent a safety 

enhancement to the already safe aerial surveys and inspections conducted with conventional aircraft and 

helicopters. Untethered, the UA can be operated and comply with ASEC exemption #11509 criteria. 

Tethered, the UA greatly mitigates nearly all risks associated with sUAS operations, to include flight in 

proximity of non-participants. ASEC shall only operate in the tethered mode.

A. 14 CFR 91.119(c) – Requirements for Minimum Safe Altitudes for Civil Aircraft Operation

1. Request relief from 500 foot requirement between flight operations and non-participating

personnel using the following equivalent safety plan.

a.Concept of Operations. The winch that houses the Kevlar coated, 600 pound 

breaking strength line that tethers the UA will be placed at a fixed position in the 

center of the flight area. A pre-determined maximum altitude will be electronically 

and mechanically locked by the winch and ground control system, preventing the UA 

from exceeding the assigned maximum altitude. A circular safety boundary will be 

established, max altitude plus 20 feet, creating a 20 foot buffer between the 

maximum horizontal distance the UA can travel and the perimeter safety boundary. 

For additional safety, a vertical physical barrier will be erected along the safety 

boundary to shield non-participating personnel from flying debris in the event of an 

accident. See Figure (1) for a depiction of the operational concept.

Figure 1 - Operational Concept
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b.Safety Plan. Tethered flight operations shall be conducted no closer than max altitude 

plus 20 feet from all nonparticipating persons, vessels, vehicles, and structures when 

all of the following conditions are met:

i. Barriers or structures are present that sufficiently protect nonparticipating 

persons from the UA and/or debris in the event of an accident. The operator 

must ensure that nonparticipating persons remain on the other side of such 

protection. If a situation arises where nonparticipating persons leave such 

protection and are within a horizontal distance of maximum altitude plus 20

feet of the UA, flight operations must cease immediately in a manner 

ensuring the safety of nonparticipating persons; and

ii. The owner/controller of any vessels, vehicles or structures has granted 

permission for operating closer to those objects and the pilot in command 

(PIC) has made a safety assessment of the risk of operating closer to those 

objects and determined that it does not present an undue hazard; and

iii. Any UAS that has undergone maintenance or alterations that affect the UAS 

operation or flight characteristics, e.g., replacement of a flight critical 

component, must undergo a functional test flight (FCF) prior to conducting

further operations under this exemption. FCF may only be conducted by a 

PIC with a visual observer (VO) and must remain at least maximum altitude 

plus 20 feet from other people. The functional test flight must be conducted 

in such a manner so as to not pose an undue hazard to persons and property.

iv. The PIC, VO, operator trainees, consensual, or essential persons are not 

considered nonparticipating persons.

B. 14 CFR 91.151 (a) (1) – Fuel Requirements for Flights in VFR Conditions

1. Relief for minimum fuel requirement, or 25 percent remaining power, using the following 

equivalent safety plan.

a.The tethered sUAS has continuous, monitored electrical power provided from a 

ground source. The ground power system is controlled by a smart charging and 

inverting system. 

b.The UA will not arm itself if there is a fault in the ground power system. A low 

voltage warning will appear on the GCS to let the operator know if there is a power 

issue. 

c.Batteries are incorporated into the ground system to power the vehicle in the event of 

an external power source, such as a generator, failure.

d.If backup power is being used, a low voltage warning will appear on the GCS letting 

the operator know that power is no longer being supplied through the tether. A 

backup battery is located onboard the UA, providing 90 seconds of power. 
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e.Should both the ground side power source (e.g. generator) and ground battery backup 

system fail, the onboard UA battery system will automatically engage without 

hesitation or power loss and is capable of powering the vehicle for up to 90 seconds. 

The vehicle will also automatically enter a failsafe mode and safely land the vehicle 

within the flight area and disarm itself. 

f. ASEC will terminate flight in the event ground power is interrupted for any reason.