July 14, 2015

Exemption No. 12036

Regulatory Docket No. FAA–2015–1376

Dr. Stephen Kwan

Northwest Hydraulic Consultants

16300 Christensen Road, Suite 350

Tukwila, WA 98188

Dear Dr. Kwan:

This letter is to inform you that we have granted your request for exemption. It transmits our 

decision, explains its basis, and gives you the conditions and limitations of the exemption, 

including the date it ends.

By letter dated May 1, 2015, you petitioned the Federal Aviation Administration (FAA) on 

behalf of Northwest Hydraulic Consultants (hereinafter petitioner or operator) for an 

exemption. The petitioner requested to operate an unmanned aircraft system (UAS) to 

conduct aerial photography.

See Appendix A for the petition submitted to the FAA describing the proposed operations and 

the regulations that the petitioner seeks an exemption.

The FAA has determined that good cause exists for not publishing a summary of the petition 

in the Federal Register because the requested exemption would not set a precedent, and any 

delay in acting on this petition would be detrimental to the petitioner.

Airworthiness Certification

The UAS proposed by the petitioner are the eBee SenseFly; DJI Phantom 2; and 3DR Iris+.

The petitioner requested relief from 14 CFR part 21, Certification procedures for products 

and parts, Subpart H—Airworthiness Certificates. In accordance with the statutory criteria 

provided in Section 333 of Public Law 112−95 in reference to 49 U.S.C. § 44704, and in 

consideration of the size, weight, speed, and limited operating area associated with the 
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aircraft and its operation, the Secretary of Transportation has determined that this aircraft 

meets the conditions of Section 333. Therefore, the FAA finds that the requested relief from 

14 CFR part 21, Certification procedures for products and parts, Subpart H—Airworthiness 

Certificates, and any associated noise certification and testing requirements of part 36, is 

not necessary.

The Basis for Our Decision

You have requested to use a UAS for aerial data collection1. The FAA has issued grants of 

exemption in circumstances similar in all material respects to those presented in your petition. 

In Grants of Exemption Nos. 11062 to Astraeus Aerial (see Docket No. FAA−2014−0352), 

11109 to Clayco, Inc. (see Docket No. FAA−2014−0507), 11112 to VDOS Global, LLC (see

Docket No. FAA−2014−0382), and 11213 to Aeryon Labs, Inc. (see Docket No. 

FAA−2014−0642), 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, gives the FAA good cause to find that the UAS operation enabled 

by this exemption is in the public interest.

Having reviewed your reasons for requesting an exemption, I find that—

 They are similar in all material respects to relief previously requested in Grant of 

Exemption Nos. 11062, 11109, 11112, and 11213;

 The reasons stated by the FAA for granting Exemption Nos. 11062, 11109, 11112, and 

11213 also apply to the situation you present; and 

 A grant of exemption is in the public interest.

Our Decision

In consideration of the foregoing, I find that a grant of exemption is in the public interest. 

Therefore, pursuant to the authority contained in 49 U.S.C. 106(f), 40113, and 44701, 

delegated to me by the Administrator, Northwest Hydraulic Consultants is granted an 

exemption from 14 CFR §§ 61.23(a) and (c), 61.101(e)(4) and (5), 61.113(a), 61.315(a), 

91.7(a), 91.119(c), 91.121, 91.151(a)(1), 91.405(a), 91.407(a)(1), 91.409(a)(1) and (2), and 

91.417(a) and (b), to the extent necessary to allow the petitioner to operate a UAS to perform 

aerial data collection. This exemption is subject to the conditions and limitations listed 

below.

 

1 Aerial data collection includes any remote sensing and measuring by an instrument(s) aboard the UA. 

Examples include imagery (photography, video, infrared, etc.), electronic measurement (precision surveying, RF 

analysis, etc.), chemical measurement (particulate measurement, etc.), or any other gathering of data by 

instruments aboard the UA.
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Conditions and Limitations

In this grant of exemption, Northwest Hydraulic Consultants is hereafter referred to as 

the operator.

Failure to comply with any of the conditions and limitations of this grant of exemption will be 

grounds for the immediate suspension or rescission of this exemption.

1. Operations authorized by this grant of exemption are limited to the eBee SenseFly; 

DJI Phantom 2; and 3DR Iris+ when weighing less than 55 pounds including payload. 

Proposed operations of any other aircraft will require a new petition or a petition to 

amend this exemption.

2. Operations for the purpose of closed-set motion picture and television filming are 

not permitted. 

3. The UA may not be operated at a speed exceeding 87 knots (100 miles per hour). The 

exemption holder may use either groundspeed or calibrated airspeed to determine 

compliance with the 87 knot speed restriction. In no case will the UA be operated at 

airspeeds greater than the maximum UA operating airspeed recommended by the 

aircraft manufacturer.

4. The UA must be operated at an altitude of no more than 400 feet above ground level 

(AGL). Altitude must be reported in feet AGL.

5. The UA must be operated within visual line of sight (VLOS) of the PIC at all times. 

This requires the PIC to be able to use human vision unaided by any device other than 

corrective lenses, as specified on the PIC’s FAA-issued airman medical certificate or 

U.S. driver’s license.

6. All operations must utilize a visual observer (VO). The UA must be operated within 

the visual line of sight (VLOS) of the PIC and VO at all times. The VO may be used 

to satisfy the VLOS requirement as long as the PIC always maintains VLOS 

capability. The VO and PIC must be able to communicate verbally at all times; 

electronic messaging or texting is not permitted during flight operations. The PIC 

must be designated before the flight and cannot transfer his or her designation for the 

duration of the flight. The PIC must ensure that the VO can perform the duties 

required of the VO.

7. This exemption and all documents needed to operate the UAS and conduct its 

operations in accordance with the conditions and limitations stated in this grant of 

exemption, are hereinafter referred to as the operating documents. The operating 

documents must be accessible during UAS operations and made available to the 

Administrator upon request. If a discrepancy exists between the conditions and 
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limitations in this exemption and the procedures outlined in the operating documents, 

the conditions and limitations herein take precedence and must be followed. 

Otherwise, the operator must follow the procedures as outlined in its operating 

documents. The operator may update or revise its operating documents. It is the 

operator’s responsibility to track such revisions and present updated and revised 

documents to the Administrator or any law enforcement official upon request. The 

operator must also present updated and revised documents if it petitions for extension 

or amendment to this grant of exemption. If the operator determines that any update 

or revision would affect the basis upon which the FAA granted this exemption, then 

the operator must petition for an amendment to its grant of exemption. The FAA’s 

UAS Integration Office (AFS−80) may be contacted if questions arise regarding 

updates or revisions to the operating documents.

8. 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 prior to conducting further operations under this exemption. 

Functional test flights may only be conducted by a PIC with a VO and must remain at 

least 500 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.

9. The operator is responsible for maintaining and inspecting the UAS to ensure that it is 

in a condition for safe operation.

10. Prior to each flight, the PIC must conduct a pre-flight inspection and determine the 

UAS is in a condition for safe flight. The pre-flight inspection must account for all 

potential discrepancies, e.g., inoperable components, items, or equipment. If the 

inspection reveals a condition that affects the safe operation of the UAS, the aircraft is 

prohibited from operating until the necessary maintenance has been performed and the 

UAS is found to be in a condition for safe flight.

11. The operator must follow the UAS manufacturer’s maintenance, overhaul, 

replacement, inspection, and life limit requirements for the aircraft and 

aircraft components.

12. Each UAS operated under this exemption must comply with all manufacturer 

safety bulletins.

13. Under this grant of exemption, a PIC must hold either an airline transport, 

commercial, private, recreational, or sport pilot certificate. The PIC must also hold a 

current FAA airman medical certificate or a valid U.S. driver’s license issued by a 

state, the District of Columbia, Puerto Rico, a territory, a possession, or the Federal 

government. The PIC must also meet the flight review requirements specified in 

14 CFR § 61.56 in an aircraft in which the PIC is rated on his or her pilot certificate.
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14. The operator may not permit any PIC to operate unless the PIC demonstrates the 

ability to safely operate the UAS in a manner consistent with how the UAS will be 

operated under this exemption, including evasive and emergency maneuvers and 

maintaining appropriate distances from persons, vessels, vehicles and structures. PIC 

qualification flight hours and currency must be logged in a manner consistent with 

14 CFR § 61.51(b). Flights for the purposes of training the operator’s PICs and VOs 

(training, proficiency, and experience-building) and determining the PIC’s ability to 

safely operate the UAS in a manner consistent with how the UAS will be operated 

under this exemption are permitted under the terms of this exemption. However, 

training operations may only be conducted during dedicated training sessions. During 

training, proficiency, and experience-building flights, all persons not essential for 

flight operations are considered nonparticipants, and the PIC must operate the UA 

with appropriate distance from nonparticipants in accordance with 14 CFR § 91.119.

15. UAS operations may not be conducted during night, as defined in 14 CFR § 1.1. All 

operations must be conducted under visual meteorological conditions (VMC). Flights 

under special visual flight rules (SVFR) are not authorized.

16. The UA may not operate within 5 nautical miles of an airport reference point (ARP) as 

denoted in the current FAA Airport/Facility Directory (AFD) or for airports not 

denoted with an ARP, the center of the airport symbol as denoted on the current 

FAA-published aeronautical chart, unless a letter of agreement with that airport’s 

management is obtained or otherwise permitted by a COA issued to the exemption 

holder. The letter of agreement with the airport management must be made available 

to the Administrator or any law enforcement official upon request.

17. The UA may not be operated less than 500 feet below or less than 2,000 feet 

horizontally from a cloud or when visibility is less than 3 statute miles from the PIC.

18. If the UAS loses communications or loses its GPS signal, the UA must return to a 

pre-determined location within the private or controlled-access property.

19. The PIC must abort the flight in the event of unpredicted obstacles or emergencies.

20. The PIC is prohibited from beginning a flight unless (considering wind and forecast 

weather conditions) there is enough available power for the UA to conduct the 

intended operation and to operate after that for at least five minutes or with the reserve 

power recommended by the manufacturer if greater.

21. Air Traffic Organization (ATO) Certificate of Waiver or Authorization (COA). All 

operations shall be conducted in accordance with an ATO-issued COA. The 

exemption holder may apply for a new or amended COA if it intends to conduct 

operations that cannot be conducted under the terms of the attached COA.
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22. All aircraft operated in accordance with this exemption must be identified by serial 

number, registered in accordance with 14 CFR part 47, and have identification 

(N−Number) markings in accordance with 14 CFR part 45, Subpart C. Markings must 

be as large as practicable.

23. Documents used by the operator to ensure the safe operation and flight of the UAS and 

any documents required under 14 CFR §§ 91.9 and 91.203 must be available to the 

PIC at the Ground Control Station of the UAS any time the aircraft is operating. 

These documents must be made available to the Administrator or any law enforcement 

official upon request.

24. The UA must remain clear and give way to all manned aviation operations and 

activities at all times. 

25. The UAS may not be operated by the PIC from any moving device or vehicle. 

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.

27. All operations shall be conducted over private or controlled-access property with 

permission from the property owner/controller or authorized representative. 

Permission from property owner/controller or authorized representative will be 

obtained for each flight to be conducted.

28. Any incident, accident, or flight operation that transgresses the lateral or vertical 

boundaries of the operational area as defined by the applicable COA must be reported 

to the FAA's UAS Integration Office (AFS−80) within 24 hours. Accidents must be 

reported to the National Transportation Safety Board (NTSB) per instructions 

contained on the NTSB Web site: www.ntsb.gov.
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If this exemption permits operations for the purpose of closed-set motion picture and 

television filming and production, the following additional conditions and limitations apply.

29. The operator must have a motion picture and television operations manual (MPTOM) 

as documented in this grant of exemption.

30. At least 3 days before aerial filming, the operator of the UAS affected by this 

exemption must submit a written Plan of Activities to the local Flight Standards 

District Office (FSDO) with jurisdiction over the area of proposed filming. The 3-day 

notification may be waived with the concurrence of the FSDO. The plan of activities 

must include at least the following:

a. Dates and times for all flights;

b. Name and phone number of the operator for the UAS aerial filming conducted 

under this grant of exemption;

c. Name and phone number of the person responsible for the on-scene operation of 

the UAS;

d. Make, model, and serial or N−Number of UAS to be used;

e. Name and certificate number of UAS PICs involved in the aerial filming;

f. A statement that the operator has obtained permission from property owners 

and/or local officials to conduct the filming production event; the list of those 

who gave permission must be made available to the inspector upon request;

g. Signature of exemption holder or representative; and

h. A description of the flight activity, including maps or diagrams of any area, city, 

town, county, and/or state over which filming will be conducted and the altitudes 

essential to accomplish the operation.

31. Flight operations may be conducted closer than 500 feet from participating persons 

consenting to be involved and necessary for the filming production, as specified in the 

exemption holder’s MPTOM.

Unless otherwise specified in this grant of exemption, the UAS, the UAS PIC, and the UAS 

operations must comply with all applicable parts of 14 CFR including, but not limited to, 

parts 45, 47, 61, and 91.
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This exemption terminates on July 31, 2017, unless sooner superseded or rescinded.

Sincerely,

/s/

John S. Duncan

Director, Flight Standards Service

Enclosures
Washington, DC 20590 

Dear Sir/ Madam: 

Pursuant to Section 333 of the FAA Modernization and Reform Act of 2012 {the Reform Act) and 14 

C.F.R. Part 11, Northwest Hydraulic Consultants {NHC), hereby applies for an exemption from the listed 

Federal Aviation Regulations {uFARs") to allow commercial operation of sUASs {small Unmanned Aircraft 

System), so long as such operations are conducted within and under the conditions outlined herein or as 

may be established by the FAA as required by Section 333. 

As described more fully below, the requested exemption would permit the operation of small, 

unmanned and relatively inexpensive sUAS under controlled conditions in airspace that is 1) limited; 2) 

predetermined; 3) controlled as to access. 

Name and Address of the applicant is 

Dr Stephen Kwan 

Northwest Hydraulic Consultants 

16300 Christensen Road, Suite 350 

Tukwila 

WA 98188 

Tel: 206 241 6000 

Email: skwan@nhcweb.com 

Relevant Qualifications 

Commercial Pilot {3664987) with the following ratings: 

1. Airplane Single Engine Land 

2. Rotorcraft Helicopter 

3. Instrument Airplane 

4. Instrument Helicopter 

5. Cert ified Flight Instructor {Helicopter) 

Total Flying time: 1100 hours 

About The Petitioner 

NHC is a specialty consulting engineering firm focused exclusively in the area of water resources. We are 

experts in flood control, water management, water supply, irrigation, river restoration and many other 

water related fields. NHC requires topographic survey and imagery of geographical areas to help us in 

environmental projects that include identifying potential areas of flooding, developing hydraulic models 

of rivers to predict areas of bank erosion and improve areas of fish habitat. NHC wishes to use sUASs to 

water resource specialists 
Proposed Commercial Uses 

NHC plans to use the following sUAS: 

• eBee SenseFiy • DJI Phantom 2 

• 3DR Iris 

The sUAS will be fitted with a digital camera to take aerial photos of river banks which can be used for 

the following purposes: 

1. Flood plain mapping 

2. Determining areas of potential erosion/ sedimentation 

3. Design of flood control and habitat restoration projects 

4. Creating Digital Elevation Maps 

5. Examining areas damaged by flooding or landslides 

We need to use a sUAS because: 

1. Access to portions of some sites is not possible due to terrain, fast river flows, or other hazards. 

2. River banks are constantly changing and we need to create up to date terrain data using aerial 

photos. 

3. We can access both sides of the river bank efficiently and safely. 

4. Creating Digital Elevation Models (OEM) from aerial photos is much more efficient and 

economical than using manned aircraft. We will subsequently be able to pass this cost saving to 

our clients. 

We have no intention of selling photos for commercial purposes. We have not yet performed any work in this field to ensure compliance with any applicable FARs 

regarding the use of UAS for commercial operations. 

Intended Operat ional Use of sUAS 

• Operation altitudes: 50-400ft AGL • Estimated Survey Area: 0.5- 600 acres 

• Flight Time: multiple 15 min flights as necessary to cover area. Typical project flight 

time estimated to be about 1 hour. 

• Airspace: Class G 

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Figure 1. Typical flight path of UAS (shown in Red) 

NHC will be bound by the following limitations when conducting its sUAS operations under an FAA 

exemption: 

1. The sUAS will weigh less than 55 lbs. 

2. Flights will be operated within line of sight of a pilot and/or observer. 

3. Maximum total flight time for each operational flight will be 15 minutes. Flights will be 

terminated at 20% battery power reserve should that occur prior to the 15 minute limit. 

4. Flights will be operated at an altitude of no more than 400ft AGL. 

5. Flight operations will occurring during daylight hours under VFR or Marginal VFR conditions. 

6. Minimum crew for each operation will consist of the sUAS Pilot and the Visual Observer. 

7. sUAS PIC will be an FAA licensed airman with at least a private pilot's certificate and third class 

medical. (Dr Stephen Kwan is a certified flight instructor and in addition holds a commercial and 

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persons involved or in the area of the survey. 

10. The sUAS will operate at least 100ft away from buildings in urbanized areas. 

11. A briefing will be conducted in regard to the planned sUAS operations prior to each survey. It 

will be mandatory that all personnel who will be performing duties within the survey area to be 

present for this briefing 

12. The operator will file a FAA Form 7711-1, or its equivalent, as modified in light of the requested 

exemption, with the appropriate Flight Standards District Office. 

13. Pilot and observer will be trained in operation of sUAS generally and receive up-to-date 

information on the particular sUAS to be operated. 

14. Observer and pilot will at all times be able to communicate by voice and/or text. 

15. Written and/or oral permission from the relevant property holders will be obtained. 

16. All required permissions and permits will be obtained from territorial, state, county or city 

jurisdictions, including local law enforcement, fire, or other appropriate governmental agencies. 

17. If the sUAS loses communications or loses its GPS signal, the sUAS will have capability to return 

to a pre-determined location and land. 

18. The sUAS will have the capability to abort a flight in case of unpredicted obstacles or 

emergencies. 

How our request would benefit the general public 

One of NHC's major area of expertise is floodplain mapping to determine the extent of flooding in the 

event of a major flood. If we are granted an exemption to use a sUAS for aerial surveying, the benefits to 

the public will be: 

1. Areas of potential landslides and flooding can be easily identified; 

2. Accurate mapping of potential areas of flooding; 

3. Increased efficiency and reduced cost of river restoration and flood control projects for our 

clients (usually Government agencies). 

Regulations from wh ich the exemption is requested: 

14 C.F.R. Part 21; 

14 C.F.R. 91.7 (a) 

14 C.F.R. 91.9(b)(2) & (c) 14 C.F.R. 91.103 14 C.F.R. 91.109: 

14 C.F.R. 91.119;14 14 C.F.R. 91.121 14. C.F.R. 91.151(a) 

14 C.F.R. 91.203(a) & (b) 

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Description of Specific Regulations 

We require an exemption in accordance with Section 333 AND a civil Certificate of Waiver or 

Authorization (COA) to operate unmanned aircraft in the National Airspace System (NAS) for commercial 

use in a low-risk, controlled environment. 

14 C.F.R. Part 21: (Aircraft certification requirements) & 14 C.F.R. 91.203(a) & (b); (Maintenance 

inspections) 

Under 14 C.F.R. § 91.203, all U.S.-registered aircraft are required to have a certificate of airworthiness 

issued by the FAA. Part 21, Subpart H of the FANs regulations establishes the procedural requirements 

for the issuance of airworthiness certificates by the FAA. 

Equivalent level of safety analysis: The strict operational limitations under which NHC will conduct 

flights for commercial sUAS applications (e.g., daylight operations, use of Class G airspace, all flights 

within line-of-sight of the operator) are at least as restrictive as the limitations that apply to the 

operation of limited or restricted category, experimental or provisionally-certificated aircraft. The sUAS 

does not carry a pilot or any other passengers and their small size and electric motor reduce the danger 

that any collisions with the ground or structures will involve anything more than the loss of sUAS. 

Automatic descent of the sUAS upon loss of the data link with its control station eliminates the potential 

for ••fly away11 incidents. The concerns behind the need for the certification of an aircraft•s airworthiness 

are mitigated by the sUAS's limited operational range, small dimensions and the use of lightweight 

materials in their construction, all of which reduce the risk of damage to surrounding structures. 

14 C.F.R. 45.23(b): "N" numbers and markings 

This regulation requires the display of an ••Nu registration mark on any U.S.-registered aircraft. 

Additional markings are required for limited or restricted category aircraft, experimental aircraft or 

provisionally-certificated aircraft on the entrance to the cabin, cockpit or pilot station. 

Equivalent level of safety analysis: The FAA has yet to indicate whether sUAS aircraft will be subject to 

its aircraft registration requirements. The FANs Integration of Civil Unmanned Aircraft Systems in the 

National Airspace System (NAS) Roadmap published in November 2013 is silent on this point. As sUAS 

aircraft are not currently required to be registered with the FAA, it is not necessary for NHC's sUAS 

aircraft to be marked with an 11 N11 registration number. The surface area of the sUAS is not large enough 

to contain any of the markings required by the FAA for limited or restricted category aircraft, 

experimental aircraft or provisionally-certificated aircraft. One of the purposes served by these markings 

is to caution passengers on board such an aircraft (including any pilot) that it does not meet all of the 

FANs requirements for a standard category certificate of airworthiness. As the sUAS will not carry any 

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on each of the control stations used to operate NHC's sUAS aircraft. 

14 C.F.R. 91.7 (a): (Civil aircraft airworthiness) 

The regulation requires that no person may operate a civil aircraft unless it is in airworthy condition. As 

there will be no airworthiness certificate issued for the aircraft, should this exemption be granted, no 

FAA regulatory standard will exist for determining airworthiness. Given the size of the aircraft and the 

requirements contained in the User Guide for maintenance and use of safety checklists prior to each 

flight an equivalent level of safety will be provided. 

14 C.F.R. 91.9(b)(2) & (c): (Flight manuals, placards) 

This regulation requires that an approved flight manual, manual material, markings, placards or 

some combination thereof be placed on board the aircraft. The sUAS does not have a configuration 

suitable for compliance with this requirement. 

Equivalent level of safety analysis: The sUAS is linked to a computer that serves as the control station. 

The instruction manual for the sUAS can be downloaded to the computer and accessed by the operator, 

in much the same way that pilots of commercial airliners are able to access flight manuals on tablet 

devices that serve as .. electronic flight bags!' All manual material, markings and placards relevant to the 

operation of the sUAS can be displayed on the screen of the computer that serves as the control station, 

as required. The instruction manual for the sUAS will therefore be just as accessible as a flight manual 

carried on board a commercial jet. 

14 C.F.R. 91.103: (pre-flight) 

This regulation requires each pilot in command to take certain actions before flight to ensure the safety 

of flight. As FAA approved rotorcraft flight manuals will not be provided for the aircraft an exemption 

will be needed. 

Equivalent level of safety analysis: The PIC will take all actions including reviewing weather, flight 

battery requirements, landing and takeoff distances and aircraft performance data before initiation of 

flight. 

14 C.F.R. 91.109: (Dual controls for instruction) 

Section 91.103 provides that no person may operate a civil aircraft (except a manned free balloon) that 

is being used for flight instruction unless that aircraft has fully functioning dual controls. sUASs and 

remotely piloted aircraft, by their design do not have fully functional dual controls. Flight control is 

accomplished through the use of a control box that communicates with the aircraft via radio 

communications. The FAA has approved exemptions for flight training without fully functional dual 

controls for a number of aircraft and for flight instruction in experimental aircraft. 

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14 C.F.R. 91.119: (Safe altitudes over obstacles) 

This regulation specifies the minimum altitude in various flight environments below which aircraft are 

not allowed to operate. NHC will conduct the commercial services it proposes to operate below the FAAspecified minimum of 500ft above the surface and closer to vessels and structures than the minimum 

separation of 500ft mandated by the FAA. 

Equivalent level of safety analysis: The operation of the sUAS aircraft exclusively in Class G airspace 

(i.e., below 1200 ft) is intended as a safety measure to provide a level of separation between NHC's 

commercial UAS operations and the operation of manned aircraft at altitudes above 1200 ft. In this case, 

limiting the sUAS to flights below the 500ft minimum will enhance safety rather than compromise it. 

NHC will need to operate the sUAS closer than 500ft to structures in order to conduct the inspections 

that will comprise a major part of NHC's commercial sUAS services. However, NHC's flight procedures 

include the company's own requirements regarding the minimum level of separation between sUAS and 

any nearby structures or facilities. In addition, the risk of damage to any nearby structures or facilities is 

reduced by sUAS's limited operational range, small dimensions and the use of lightweight materials in its 

construction. 

14 C.F.R. 91.121: Altimeter Settings 

This regulation requires each person operating an aircraft to maintain cruising altitude by reference to 

an altimeter that is set " ... to the elevation of the departure airport or an appropriate altimeter setting 

available before departure." As the sUAS may not have a barometric altimeter, but instead a GPS 

altitude read out, an exemption is needed. 

Equivalent level of safety analysis: The operator, pursuant to the Manual and Safety Check list, will 

confirm the altitude of the launch site shown on the GPS altitude indicator before flight. 

14 C.F.R. 91.151{a): (Fuel minimums) 

FAA regulations require that a rotorcraft operating under VFR conditions have sufficient fuel to 

fly to the first point of intended landing and, assuming normal cruising speed, to fly for at least an 

additional 20 minutes. The sUAS has a maximum operating time of 20 minutes. 

Equivalent level of safety analysis: The FAA's regulations require sufficient reserves of additional fuel to 

enable a rotorcraft to find the nearest suitable landing zone if the intended landing facility is not available. The additional time that a rotorcraft is required to be able to operate is less than the time 

required to allow fixed-wing aircraft to find a suitable landing field (30 minutes during the day, 45 

minutes at night) reflecting the relative scarcity of landing fields for aircraft versus landing zones suitable 

for rotorcraft. By similar logic, the additional fuel required for sUAS aircraft should be dramatically less 

7 
structures. 

14 C.F.R. 91.203(a) & (b): (Maintenance inspections) 

The regulation provides in pertinent part: 

(a) Except as provided in§ 91.715, no person may operate a civil aircraft unless it has within it the 

following: 

(1) An appropriate and current airworthiness certificate .... 

(b) No person may operate a civil aircraft unless the airworthiness certificate required by paragraph (a) 

of this section or a special flight authorization issued under §91. 715 is displayed at the cabin or cockpit 

entrance so that it is legible to passengers or crew. 

The UAS fully loaded weighs no more than 55 lbs and is operated without an onboard pilot. As such, 

there is no ability or place to carry certification and registration documents or to display them on the 

sUAS. 

Equivalent level of safety analysis: An equivalent level of safety will be achieved by keeping these 

documents at the ground control point where the pilot flying the sUAS will have immediate access to 

them, to the extent they are applicable to the sUAS. 

14 C.F.R. 91.405(a) & 14 C.F.R. 91.407(a)(1): 14 C.F.R. 91.409(a)(2): 14 C.F.R. 91.417(a): 

(Maintenance related) 

FAA regulations impose various requirements regarding the maintenance of civil aircraft, including 

periodic inspections, approval for return to service by a qualified mechanic following maintenance or 

repair, an airworthiness inspection and certain rules concerning maintenance record keeping. NHC's maintenance of the sUAS aircraft will not satisfy these requirements. 

Equivalent level of safety analysis: NHC will maintain the sUAS in accordance with the manuals and 

operating handbook provided by the manufacturer. Because of the sUAS's small size and lightweight 

construction, NHC will be able to subject it to top-to-bottom examination after every flight. All pre- or 

post-flight maintenance, equipment failures, charge cycle logs, fault/repair logs, inspections and general 

maintenance records will be kept on file for a minimum of three years. NHC has developed a lengthy 

pre/post-flight checklist; any aircraft which is unable to meet all the requirements for safe operation will 

be removed from service immediately and will not return to service until any defects have been 

remedied. Moreover, if mechanical issues arise, the sUAS can land immediately as they will be operating 

at an altitude no higher than 500ft. 

The manufacturers periodically update parts and software for sUAS aircraft. When a 

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Summary 

This application seeks an exemption from the FARs set forth above to allow commercial operations of a 

small unmanned aircraft system to conduct precision aerial surveys for the benefit of the general public. 

Yours sincerely 

Dr Stephen Kwan CFI 

River Engineer 

Northwest Hydraulic Consultants 

't~+'\')~ 

Todd Bennett P.E 

Branch Manager 

Northwest Hydraulic Consultants 

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