Fovea Aero Systems LLC

60 Fostertown Road  Medford, New Jersey 08055

Phone: 888-623-4623  E-Mail: jeff@foveaaero.com  Web: www.FoveaAero.com

Date: May 13, 2015

U.S. Department of Transportation

UAS Integration Office (AFS-80)

Federal Aviation Administration

800 Independence Avenue, SW

Washington, DC 20591

Dear Sir or Madam:

Fovea Aero Systems LLC (“Fovea Aero”) has submitted for a Section 333 exemption pursuant to the 

FAA Modernization and Reform Act of 2012 (the “Reform Act”) and 14 C.F.R. Part 11, to allow for the 

commercial operation of its sUASs (docket FAA-2015-0545). As of the date of this letter, Fovea Aero is 

awaiting the FAA’s decision.

In anticipation of that decision, and based on past exemptions granted by the FAA for the commercial 

operation of sUASs in the national airspace, Fovea Aero hereby requests the FAA to allow the included

alternate method of compliance for the condition and limitation often referred to in granted exemptions 

as “Condition and Limitation 26” (hereafter “Limitation 26”).

It states:

26. All Flight operations must be conducted at least 500 feet from all nonparticipating 

persons, vessels, vehicles, and structures unless: 

a. 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 under such protection. If a situation arises 

where nonparticipating persons leave such protection and are within 500 feet of the 

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

nonparticipating persons; and 

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

for operating closer to those objects and the 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. 

The PIC, VO, operator trainees or essential persons are not considered nonparticipating 

persons under this exemption. 

The purpose of this condition is to protect nonparticipating persons, vessels, vehicles and structures 

from harm in the event of an accident during UA flight operations. Fovea Aero Systems LLC is 

dedicated to safe operations while providing a significant public benefit through the commercial 

operation of its sUASs. In order to achieve this, Fovea Aero hereby proposes the following alternate 

method of compliance for Limitation 26 and contends it meets or exceeds the intended purpose of this 

limitation.

Page 3

The kinetic energy available during a crash has a direct physical effect on the work that can be done by 

that energy. Less energy available means that potential debris volume and distance will be reduced as 

well as potential damage to vessels, vehicles and structures in the event of an accident. The 96% 

reduction in energy in an S1000+ at gross weight and at the maximum imposed speed restriction would 

be expected to result in much less damage and smaller debris fields during a crash as compared to the 

previously approved UASs operating under Limitation 26.

C. Limitation 26 and Accident Energy

The distance limitation of 500 feet set forth in Limitation 26 applies to the wide variety of aircraft 

covered by the limitation. Aircraft, “...when weighing less than 55 pounds including payload,” and 

when not, “...operated at a speed exceeding 87 knots (100 miles per hour)”2 are permitted to operate at a 

distance of 500 feet from nonparticipating persons, vessels, vehicles and structures.

Fovea Aero Systems LLC contends that with appropriate speed restrictions and with lighter aircraft, 

these limitations can be safely reduced while meeting or exceeding the safety afforded to 

nonparticipating persons as compared to operations as approved in previously issued exemptions. The 

11 Kg gross weight of the S1000+ and a speed limitation of 30 mph would significantly reduce the 

kinetic energy of the aircraft resulting in less damage in the event of an accident. This allows the 

aircraft to safely operate with a lower distance restriction than that set forth in Limitation 26.

II. Advanced Safety Features

Specific UAS designs can be equipped with additional features and systems that further enhance the 

safety of the aircraft and reduce the risk of injury and damage to participating and nonparticipating 

persons, vessels, vehicles and structures in the event of an accident. These features can provide several 

advantages over non-equipped aircraft and can allow operation of the aircraft with alternative 

conditions and limitations while meeting or exceeding the protections afforded by the current Section 

333 limitations.

A. “DJI DropSafe” Airframe Parachute System

The S1000+ can be equipped with the “DJI DropSafe” full airframe parachute system. This system is 

automatically and / or manually deployed in the event of a malfunction, an imminent accident, a 

flyaway, main battery malfunction, or other anomaly that may result in a crash.

The DropSafe system monitors its own health and system status and provides the operator with a visual 

“READY” indication when the system is properly initialized and has passed its internal checks. The 

DropSafe system also connects to the aircraft’s flight control system and monitors aircraft health and 

flight parameters. The parachute will automatically deploy if the system detects fatal malfunction.3

The operator can also manually deploy the parachute. When configured as described in the user 

manual, activation is performed using a two-switch combination on the operator’s ground station. One 

switch is a safety-switch and the other is the activation switch. First the safety switch is triggered 

 2 FAA exemption number 11467.

3 DJI website, http://www.dji.com/product/dropsafe.
Page 4

followed by the activation switch. The safety-switch and activation switch combination guards against 

accidental manual deployment of the parachute.

DropSafe uses its own backup battery and receiver and can be deployed even in the event of a total 

power loss on the aircraft due to a main battery malfunction.

The DJI DropSafe parachute deploys in 0.5 seconds and can be activated as low as 6 meters. At a 

vehicle weight of 11 Kg, the system lowers the entire aircraft to the ground in a controlled descent at 

the reduced speed of approximately 7.8 m/s (17.5 mph)4.

Using the equation for kinetic energy, this results in 335 Joules of available kinetic energy at a gross 

weight of 11Kg. This is a 66% further reduction of available energy in the event of an accident as 

compared to an S1000+ at gross weight traveling at the imposed 30 mph speed limitation. Additionally, 

it is only 1.3% of the energy available in the FAA allowed UAS weighing 55 pounds and traveling at 

100 mph. This is a 98.7% reduction in energy.

Aircraft Weight Speed Energy

UAS covered by Limitation 26. 55lbs (24.95Kg) 100mph (44.7m/s) 24,926 Joules

S1000+ with maximum speed of 30 mph. 25lbs (11Kg) 30mph (13.41m/s) 989 Joules

S1000+ descending under DropSafe 

parachute.

25lbs (11Kg) 17.5mph (7.8m/s) 335 Joules

This further reduction in available kinetic energy will result in significantly less damage or debris, or 

even no damage or debris, in the event of an accident when compared to previously approved aircraft 

subject to the 500 foot limitation of Limitation 26.

The trajectory of an aircraft descending under parachute can also be significantly different than a nonprotected aircraft traveling horizontally when a malfunction occurs. Should a malfunction occur while 

the aircraft is traveling horizontally and the airframe parachute is deployed, the majority of the 

horizontal momentum will be reduced or eliminated. An aircraft descending under a parachute will 

ultimately be travelling in a generally straight down direction. This can further limit debris, if any is 

created, to a localized area around the final landing point of the aircraft.

Furthermore, the DropSafe system when activated automatically disables the motors on the S1000+.5

This causes the rotors on the aircraft to stop spinning within seconds of deployment. The disabled 

motors and stopped rotors will significantly reduce or even eliminate potential injury or damage to 

nonparticipating persons, vessels, vehicles or structures when compared to an aircraft under power with 

spinning rotors or propellers.

 4 Data obtained from “DJI DropSafe User Manual v1.2”.

5 When installed using compatible equipment and according to the directions contained in the “DJI DropSafe User 

Manual v1.2”.
Page 5

B. Limitation 26 and the DJI DropSafe Airframe Parachute System

The distance limitation of 500 feet set forth in Limitation 26 applies to the wide variety of aircraft often 

covered by the condition. Aircraft, “...when weighing less than 55 pounds including payload,” and 

when not, “...operated at a speed exceeding 87 knots (100 miles per hour)”6 are permitted to operate at a 

distance of 500 feet from nonparticipating persons, vessels, vehicles and structures.

Fovea Aero Systems LLC contends that with the DJI DropSafe system, when maintained and enabled 

according to the instructions in the DJI DropSafe User Manual, these limitations can be safely reduced 

while meeting or exceeding the safety afforded to nonparticipating persons as compared to operations as 

approved in previously issued exemptions. The further reduction in available kinetic energy (only 1.3% 

of energy available in a 55 pound aircraft traveling at 100 mph), the downward controlled descent of an

aircraft landing under a parachute and the automatic motor cutoff, provides additional safety margins 

over previously approved sUAS operations. This allows the Fovea Aero Systems LLC’s aircraft to

safely operate with a lesser distance restriction than that set forth in Limitation 26.

III. Current Operations Using Manned Aircraft

Many of the operations for which Fovea Aero Systems LLC has requested an exemption are currently 

performed by manned aircraft; often helicopters. Manned helicopters contain a pilot and often 

crewmembers, carry flammable fuel and can have a gross weight of 5,000 pounds or more.7

A. Federal Aviation Regulation 91.119 and Helicopter Operations

14 C.F.R. 91.119 states the following:

91.119 Minimum safe altitudes: General.

Except when necessary for takeoff or landing, no person may operate an aircraft below the 

following altitudes:

(a) Anywhere. An altitude allowing, if a power unit fails, an emergency landing without 

undue hazard to persons or property on the surface.

(b) Over congested areas. Over any congested area of a city, town, or settlement, or over 

any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle 

within a horizontal radius of 2,000 feet of the aircraft.

(c) Over other than congested areas. An altitude of 500 feet above the surface, except over 

open water or sparsely populated areas. In those cases, the aircraft may not be operated 

closer than 500 feet to any person, vessel, vehicle, or structure.

(d) Helicopters, powered parachutes, and weight-shift-control aircraft. If the operation is 

conducted without hazard to persons or property on the surface—

(1) A helicopter may be operated at less than the minimums prescribed in paragraph (b) 

or (c) of this section, provided each person operating the helicopter complies with any 

routes or altitudes specifically prescribed for helicopters by the FAA; and

 6 FAA exemption number 11467.

7 Airbus Helicopters AS350 according to data obtained from http://airbushelicoptersinc.com/products/AS350B2-

specifications.asp.
Page 6

(2) A powered parachute or weight-shift-control aircraft may be operated at less than 

the minimums prescribed in paragraph (c) of this section.

14 C.F.R. 91.119(d)(1) permits a helicopter to operate lower than, “...500 feet above the surface...” and 

closer than “...500 feet to an person, vessel, vehicle, or structure...” when, “...the operation is conducted 

without hazard to persons or property on the surface.”

Helicopters performing the duties Fovea Aero 

Systems LLC intends to perform with sUASs 

will often operate at these reduced limitations.8 

The helicopter may be in the general area, or 

even over, nonparticipating persons, vessels, 

vehicles, or structures at distances less than 500 

feet. An accident with a helicopter at these 

distances could be catastrophic with significant 

damage or destruction of property and fatal to 

aircraft occupants or persons on the ground. 

This is mostly due to the kinetic energy 

available in the aircraft and often the flammable 

fuel carried onboard.

B. Helicopter vs. sUAS Operations

14 C.F.R. 1.1 defines a helicopter as:

Helicopter means a rotorcraft that, for its horizontal motion, depends principally on its 

engine-driven rotors. 

A certified helicopter may operate at distances less than 500 feet from nonparticipating persons, vessels, 

vehicles or structures according to 14 C.F.R. 91.119(d)(1). Fovea Aero Systems LLC contends that an 

sUAS using the additional safety measures outlined in this document and when operated at reduced 

minimum distances as compared to Limitation 26, meets or significantly exceeds the safety provided by 

a manned helicopter performing the same operations and operating at the FAA allowed reduced 

distances described in 14 C.F.R. 91.119(d)(1).

IV. Proposed Conditions and Limitations

Given the information provided in this document and the additional limitations proposed below, Fovea 

Aero Systems LLC hereby petitions the FAA for the following alternate conditions and limitations.

Alternate Conditions and Limitations

Fovea Aero Systems LLC proposes the following conditions and limitations:

 8 A helicopter operating in the immediate vicinity of an RV park while performing power line inspections. Photo 

from “Electric Co-op Today”: http://www.ect.coop/weather-effects/preparedness/troubleshooting-in-deepwater/12631.
Page 7

26. All Flight operations must be conducted at least 500 feet from all nonparticipating 

persons, vessels, vehicles, and structures unless: 

a. 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 under such protection. If a 

situation arises where nonparticipating persons leave such protection and are 

within 500 feet of the UA, flight operations must cease immediately in a manner 

ensuring the safety of nonparticipating persons; and 

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

permission for operating closer to those objects and the 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. 

These limitations may be reduced from 500 feet to 200 feet when:

a. The aircraft operated is a DJI S1000+;

b. The aircraft is at or below its maximum takeoff weight of 11Kg (25 pounds);

c. The aircraft does not exceed a maximum speed of 30 mph;

d. The S1000+ is equipped with the DJI DropSafe aircraft parachute system;

e. The DropSafe system is installed, maintained and inspected according to the 

DJI DropSafe User Manual v1.2;

f. The DropSafe system is active and ready for deployment;

g. The PIC is familiar with the operation of the DropSafe system;

h. The DropSafe manual is available to PIC during operation;

i. The PIC discontinues the flight should it become apparent the DropSafe system 

is no longer active and ready for deployment; and

j. The PIC has made a safety assessment of the risk of operating at the reduced 

distance limitation and determined that it does not present an undue hazard.

The PIC, VO, operator trainees or essential persons are not considered nonparticipating 

persons under this exemption. 

Fovea Aero Systems LLC contends, given the size, weight and speed limitation of the sUASs in 

operation and the added protections and safety afforded by the DJI DropSafe system, the proposed 

alternate conditions and limitations meet or exceed the safety of those set forth by the FAA in 

previously granted Section 333 exemptions.

The applicant is thankful for the Federal Aviation Administration’s time and consideration.

Respectfully yours,

Jeffrey Sassinsky

President, Fovea Aero Systems LLC