Pilot's Operating 

Handbook

Copterra AP-1 Multirotor Unmanned 

Aerial System
Copterra AP-1 Pilot's Operating Handbook

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Published June 2015

Table of Contents

Table	of	Contents

Introduction ......................................................................................................................................3

Performance Specs ............................................................................................................................4

Power Distribution Map.....................................................................................................................5

Front and Top View............................................................................................................................6

Component Descriptions....................................................................................................................7

Emergency Operations.......................................................................................................................8

Environmental Limitations.................................................................................................................9

Preflight Check.................................................................................................................................10

Power Up and Takeoff Procedure .....................................................................................................11

Landing Procedure ...........................................................................................................................12

Maintenance ...................................................................................................................................13

Additional Cautions..........................................................................................................................14
Copterra AP-1 Pilot's Operating Handbook

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Published June 2015

Introduction

This manual provides an overview of the Copterra AP-1, including specifications, 

preflight procedures, emergency procedures, required maintenance and operational best 

practices. The Copterra AP-1 is a multirotor unmanned aerial system (UAS) equipped with six 

motors. It has been designed to carry HDSLR cameras on short aerial video and photography 

missions in controlled environments. For ideal flight performance, the sensors payload should 

not exceed 1 kg. It is designed to be used with the Panasonic GH4 camera or a lighter weight 

alternative.

The AP-1 is not equipped for large scale surveys, and should only be flown for missions 

requiring less than twelve minutes flight time. This manual assumes that the mission being 

flown fits this description. Any other uses of the aircraft should be evaluated, and this manual 

revised to reflect them.

The Pilot in Command must be a qualified airman, holding at minimum a Private Pilot's 

License for either fixed wing or rotor wing aircraft and a minimum Class 3 medical. If sensors 

operation and/or monitoring is required, this is to be accomplished with the help of a Flight 

Technician. The Flight Technician is also responsible for monitoring in flight telemetry. All 

commercial flight operations require that a Flight Technician be on site, and connected to the 

AP-1 via computer telemetry. The aircraft must also remain within visual line of sight of both 

the Pilot and Flight Technician.

Please see any relevant documentation from the Federal Aviation Administration 

regarding regulatory limitations to flight operations. These include published rules regarding 

unmanned aircraft, the limitations put forward in the company's Section 333 Exemption 

Request, and any other official communications.

All Pilots and Flight Technicians are required to read this manual in full before they are 

authorized to control the AP-1. This manual must also be kept in printed form near the ground 

station during missions, accessible by the Flight Technician and PIC. Preflight checklists are to 

be printed and laminated separately for quick and easy reference.
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Performance and Specifications

Weights and Dimensions

All Up Weight (Unladen)*

1

: 4.37 kg / 9.63 lb

All Up Weight (GH4 Payload): 5.98 kg / 13.18 lb

Airframe Diameter: 34"

Height: 12.5"

Rotor Length: 14"

Motors

Motors: Axi 2826/12 (6)

RPM At Hover (with GH4): ~9,000 RPM

Rotor Tip Speed at Hover (with GH4): ~562 ft/s

Max RPM: 15,000 RPM

Note: Throttle has been limited to prevent excessive motor speed.

Tip Speed at Max RPM: ~937 ft/s

Power

Power Source: 3x 5s Lipo Batteries @ 16.40 volts max

Nominal Draw (Total Drive): 806.4 Watts

Average Flight Time at Sea Level: 25.5 Minutes

Airspeed Limits

Velocity Never Exceed (VNE) 38 Knots Indicated Airspeed (KIAS)

Maximum Structural Cruise (VNO) 22 KIAS

Maneuvering Speed (VA) 15 KIAS

*1: Includes batteries and all required equipment.
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-

						

Power is transformed to +5v at the Electronic Speed Controllers (ESCs). The APM 2.5 Flight 

Controller Board is able to provide additional power to the receiver, GPS and telemetry transmitter. The 

camera servos and APM board itself receive power directly from the ESCs.
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Copterra AP-1 Pilot's Operating Handbook

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Component Descriptions

Flight Control Board: Flight control is provided by the 3D Robotics APM 2.5. The APM interprets inputs 

from the controller, translates these to motor speed signals, and monitors the attitude, altitude and 

position of the aircraft. It is also able to perform automated flight maneuvers for emergency situations, 

including failsafe landing in the event of a loss of controller communication. Power is routed through 

ESC 1 to the APM 2.5 as a +5v feed. Enough current is available to power the GPS, telemetry transmitter, 

and receiver. Power should not be pulled through the APM 2.5 for any other systems, or power 

shortages are a serious risk. All configurations to the APM 2.5 are left to the manufacturer's manuals for 

clarification. Any changes must be followed by extensive flight testing before field use.

Control Transmitter and Receiver: Pilot input is transmitted by the Spektrum DX8, paired with the 

AR8000 8-channel receiver. These inputs are then sent to the appropriate input channels on the APM 

2.5.

Telemetry: Telemetry feeds are sent and received through the 3DR Telemetry Set. This set provides a 

two way link between the aircraft and a ground station. This transmits position, attitude, voltage and 

other data to the ground station. It also allows the aircraft to receive commands from the ground 

station for emergency procedures.

Motors: The AP-1 is powered by six AXI-2826/12 motors, with 14 inch rotor blades attached. See the 

manufacturer's data sheet for specifications on these motors.

GPS: The U-Blox NEO-7 GPS provides position data to the flight control board. See the manufacturer's 

data sheet for any necessary specifications and configuration information.

ESC: The Electronic Speed Controllers translate the signal from the flight control board to a throttle level 

at the motors. This aircraft uses RC Timer 50 amp ESCs with SimonK firmware, with default settings. See 

the RC Timer manuals for more information on this component. 

Voltage Monitor: Voltage and current information is provided by the AttoPilot 90A Voltage and Current 

Sense Breakout. This has been tested accurate to +/- .5 volts and +/- 1 amp. Voltage and current 

readouts are sent to the APM 2.5, which transmits this information via the telemetry link to the ground 

station. This provides a readout of the current battery charge level (averaged across all three batteries). 

The flight technician must ensure that this is monitored at all times, to reduce the risk of a loss of power 

during flight.
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Emergency Operations

Crash Landings: If a crash landing is necessary, note that the spinning rotor blades are much 

more dangerous than the force of impact from the AP-1. As such, during any imminent crash 

the pilot must cut all throttle to zero immediately to prevent serious damage to people or 

properties.

Single Motor Failure: In the case of a single motor failure, the pilot can compensate for the 

imbalanced torque by applying approximately 3/4 yaw input as needed. Testing flights have 

shown this to allow for controllable flight. Land immediately in the nearest available location.

Multiple Motor Failures: In multiple motor failures, the torque controls may or may not be 

useful, depending on which motors have failed. If the above corrections do not work, a crash 

landing is necessary. Cut throttle to zero immediately to prevent the blades from spinning in 

case of impact.

Failure to Disarm After Landing: If the AP-1 does not disarm after landing, attempt to disarm 

via the ground station software. If this does not work, ensure that the pilot is in 'stabilize' 

mode, and is holding the controller with the throttle at zero. The flight technician must then 

place a cover over the rotor blades- a towel or shirt, for example- to prevent them from 

spinning. The flight technician may then remove the battery connections, making sure to keep 

clear of the rotor blades. 

Impact With Airborne Object: In the case of impact with an airborne object, the AP-1 may or 

may not suffer damages. The highest risk is damage to one rotor blade. In this case, refer to the 

procedures for motor failure. Even if there is no apparent change in flight characteristics, land 

immediately at the nearest location.

Note: In any emergency situation, or suspicion of technical failures, the pilot must land 

immediately. Do not attempt to return to the designated landing site if a suitable location 

requiring less transit is available.

If there is any risk of impact with people or properties on the ground, the pilot is required to cut 

all throttle immediately. While this may result in the loss of the AP-1, the impact on the ground 

will be minor when compared to the danger posed by the quickly spinning rotor blades.
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Environmental Limitations

Wind: The AP-1 is designed to fly in winds up to 10 miles per hour. While it has been tested to 

perform safely in winds up to 15 miles per hour, the limitations of battery life make this 

impractical. If there is any question, the pilot must consult a weather reporting service to see 

both the current recorded wind speed and the forecasted wind speed before making a 

go/no-go decision. 

Rain: This aircraft does not feature any weatherproofing. As such, no rain is allowable during 

flights. If rain is observed during a flight, the pilot is to land immediately following normal 

landing procedures. If the site is actively raining, the aircraft may not be launched.

Obstacles: Do not fly within 50 feet of any raised power lines or communications wires. When 

flying near trees, houses, or other objects, observe the separation before engaging in the flight 

mission to ensure no collisions are likely. Remember that the AP-1 is a larger than average 

sUAS, and therefore is not suitable for maneuvering through tight spaces.

RF Interference: Radio frequency interference can disrupt telemetry, controller input and 

compass readings on the aircraft. This is not an issue in rural environments. However, when 

operating in industrial or urban settings, the flight crew must have access to an RF Spectrum 

Analyzer. Consistent readings greater than -50 dBm in the 2.4 GHz range are considered 

dangerous to flight operations.

People and Property: Do not fly in any manner that endangers people or property not 

connected directly to the mission being flown. For video and photography work, the AP-1 must 

only be flown in controlled, closed environments, in which all activities in the immediate area 

are under the control of the flight team or its hiring agent.
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Normal Operations

Before the first flight of the day, the Pilot is responsible for checking any available weather 

forecast data, NOTAMS and other relevant information. 

Preflight Check

To be performed before every flight

To be completed before batteries are added.

1. Choose take off and landing site. Site should be even and as level as possible with no nearby 

obstacles. If necessary, place a launching/landing pad in a suitable location.

2. Visually inspect the aircraft for any apparent defects, including damage to the rotor blades.

3. Ensure that the eight screws (on either side of four spacers) attaching the camera gimbal and 

landing skids to the main airframe are secure.

4. Ensure that the rotor blades are attached securely to the motors. This is done by grasping 

each motor in succession and attempting to rotate the rotor blades while the motor remains 

stationary. If the rotor blades are able to move independently, they must be removed and 

replaced with thread locker and a tightened nut.

5. Check that all connectors between motors and electronic speed controllers are secure.

6. Look for any stray wires or other obstacles that may be struck by the rotors on power up.

7. Attach sensors payload to appropriate mount. Platform should be placed in neutral position 

before power on.

8. Attach batteries to Velcro platform. Connect safety straps, ensuring that wires are not left 

loose.
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Powering On And Take Off

1. Ensure that transmitter is powered on, throttle is placed in the lowest position, pitch/roll axis 

is neutral and the transmitter has sufficient battery power available for the mission. All toggle 

switches should be in the neutral position, which is towards the rear or top of the transmitter, 

depending on orientation.

2. The Flight Technician or individual connecting batteries must announce, 'Batteries Hot!' 

verbally. Connect batteries to power distribution system. At this time the Flight Technician and 

any other individuals on the ground should move to a safe distance (greater than 30 feet away) 

from the AP-1.

3. Connect telemetry system on appropriate ground station. A 3D GPS fix must be established 

before arming the aircraft in case of failsafe.

4. Observe for traffic or other hazards. When ready, the pilot must announce verbally, "ArmingStand Clear!". Arm the AP-1 by holding the throttle stick all the way down and to the left for 

four seconds.

5. Provide minimum throttle to the aircraft. Observe for tilt, and compensate with the pitch/roll 

controls before advancing to take off power.

6. Raise throttle slowly to ~60% to engage hover and climb to the necessary altitude. 

The Flight Technician should monitor the ground station during all flight operations to ensure 

altitude, velocity and battery drain do not exceed limits. In the absence of a Flight Technician 

(such as during test flights and practice flights), the Mission Planner software provides the 

option of a voice assist. This software should be programmed to read, at minimum, altitude and 

battery charge remaining every thirty seconds.

The AP-1 must land if battery charge reaches 20% or less. During extended flights, or flights 

taking place in adverse wind conditions, it is the pilot in command's responsibility to land with 

enough excess battery charge to safely reach the designated landing site.
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Landing

Landing approaches should be made at an angle of 50 degrees, assuming 0 degrees is the 

ground plane and 90 degrees is vertical. This angle will prevent the aircraft from interacting 

with its own turbulent air. Landing sites must be chosen in advance (usually the original launch 

site). Ensure no obstacles are near the landing site and that no people or property is 

dangerously close. The last portion of the approach must be made at as low of a vertical speed 

as is practical. The first contact point on the landing gear should be the front or back ends of 

the skids, never the sides.

Note that the APM 2.5 is primarily flown in 'Stabilize' mode, which keeps the aircraft pitched to 

match the user controls. This means that landing on uneven ground may result in an 

undesirable throttle up on one side of the aircraft as the flight controller attempts to keep level 

flight. Landing sites should be as level as possible. In the case that the landing site is not 

perfectly level, the pilot must input corrective roll and pitch levels matching the desired landing 

angle. Approach as slow as possible during this maneuver to ensure that the ground is not 

impacted too quickly, which could potentially cause damage to the payload and/or sensors 

mount.

Immediately after landing, disarm the AP-1 by holding the throttle stick all the way down and to 

the right for four seconds. Slightly raise the throttle, ensuring that the motors do not spin. If 

they do, attempt to disarm again. Announce verbally 'Disarmed!' when complete. The flight 

technician or pilot is now clear to approach and disconnect the batteries from the power 

distribution system. This should be done immediately. Do not leave batteries connected to the 

aircraft. The pilot must remain with his or her hands on the flight controls until the batteries are 

disconnected completely.
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Maintenance

Basic checking of structural components is to be done before each flight. Additional 

maintenance requirements must be completed and logged every six months. The steps for 

these are outlined below.

1. Check all structural components. The person performing maintenance should observe that 

all screws, spacers and other structural elements are securely attached to the primary airframe. 

The arms should not be able to be rotated, pulled out or pushed in using moderate force. If 

they are able to be moved, the airframe is not tightened securely.

2. Balance rotor blades. Remove all rotor blades. Using a standard propeller balancing 

apparatus and standard practices, ensure that all rotor blades are balanced to center as well as 

possible.

3. Clean motors. Remove the motors from the arms. Remove the rotor from the stator. Using 

compressed air, clean any dust or other contaminants from the windings and insides of the 

rotor. Reassemble.

4. Measure arm length. Using a tape measure, ensure that the distance between the motors 

and the edge of the airframe plates is the same for all arms. 

5. Check for level rotor blades. Place the AP-1 on a level surface. Using some form of leveling 

device, make sure that each rotor blade is also level. If any are not, readjust until they are. 

6. Range test transmitting equipment. The ground station software and remote control 

transmitter each contain range testing features. During six month maintenance, it is important 

to ensure that telemetry and control signals are transmitting at full power. A strong signal 

should be received from both up to one mile from the source in open space. The equipment in 

question may need to be replaced if signal degradation is observed.

7. Check for wire insulation. All wiring in the AP-1 should be covered in heat shrink or electrical 

tape to prevent shorts. Both of these are prone to occasional slipping. Make sure that no metal 

is visible from any wire, and replace the insulation if any metal has been exposed.

It is the responsibility of the Pilot in Command to note any abnormalities during flight at all 

times. If there is any suspicion of damaged components, loose connections or other potential 

problems, all flight operations must cease until the problem is identified and corrected. Safety 

is of paramount concern at all times. The six month maintenance procedure and preflight 

checklist do not exempt the pilot and ground crew from being vigilant at all times.
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Additional Cautions

Damage: Flying the AP-1 with any damaged components may cause serious injury or death and is strictly 

forbidden. It is the responsibility of the Pilot in Command to ensure that the aircraft is fully functional at 

all times.

Area Restrictions: This aircraft is intended to flown only over controlled areas, in which all activities and 

individuals are directly under the control of either the flight team or their employer. All individuals in the 

operational area must be informed that unmanned flights are taking place, and must consent to being 

near these operations. Do not fly over uninformed bystanders or in any environment in which the 

activities and events may be unpredictable. Further permission must be obtained from the site owner at 

any flight location.

Flight Maneuvers: Aerobatic maneuvers are forbidden. The AP-1 is intended to be flown only in 

translational and orbital movements. High speed, high pitch movements are considered too risky for an 

aircraft of this weight class. All maneuvers should be flown with as little pitch and roll as possible, and at 

as low of a velocity as is reasonable.

Payload Balancing: Any payload added to the AP-1 must be properly balanced. The flight control system 

is able to compensate for loads substantially far from the center of gravity, but doing so causes higher 

strain on some motors than others. This results in substantial wear on the motors, and reduces the 

efficiency of the flight (potentially altering flight time). The mounted camera gimbal is centered directly 

under the center of gravity; this is the only reliable way to add any payload to the AP-1.