Hx8 – Inspections

The Hx8 follows the same general inspection timetable and inspection procedures as all H6 carriers.

General Inspection Timetable (All H6 Carriers)

Description	Platform	Interval
Pre-Flight Checklist	All	Each Flight
Air Filter Replacement	H6-EFI	Every 25 hours
Battery Replacement	All	Every 150 hours
Generator Replacement	H6-EFI	Every 300 hours
Fuel Cell Replacement	Hydrone	Every 300 hours
Motor Replacement	All	Every 450 hours
ESC Replacement	All	Every 450 hours
Full Maintenance Inspection	All	Every 600 hours
Full Aircraft Review	All	Every 1000 hours

Fastener Inspection

There are over 900 individual pieces of hardware that fall under the fastener and hardware category in one Harris Aerial UAS. Keeping track of each of these before every flight not only ensures the most efficient performance of your aircraft, it also helps to certify the safety of your crew and civilians that may be in the immediate area.

The "Fastener and Torque Specifications" tables, Appendix A, should be used in conjunction with the procedures below to identify the location of each component and its associated hardware. Be sure to give extra attention to whether or not the fastener requires loctite and a specific torque specification when fixing or replacing hardware.

Inspection Procedure

Inspection Procedure	Action
Check witness marks	If a witness mark (paint) between a fastener and the component appears to have shifted from true, this is an indication the fastener has loosened and will need to be fixed.
Check for missing hardware	If a fastener or related hardware appears to be missing, it should be replaced before any flight. Refer to Appendix A for the specific requirements for each component.
Check torque specifications	Periodically, a torque and loctite inspection should be performed. To do this, use a torque screwdriver(s) capable of 0.3 N-m to 4.5 N-m of applied force. Apply 0.3 N-m under the required specification for the fastener being tested. If a fastener shifts while performing this check, it may need loctite re-applied. Refer to Appendix A for specific torque and loctite requirements.
Check fastener for cross threading or stripping	If a fastener head shows signs of stripping or cross-threading, replacement is highly recommended. Refer to Appendix A for specific requirements.

Lower Frame Inspection

The lower frame consists of two major assemblies, which include: landing gear and payload support. Inspection of these two areas before every flight will prevent aircraft landing failure and potential damage to your payload solution (ie; cameras, sensors, etc.). If in the event there is a component failure, ordering a replacement is recommended.

Landing Gear Inspection

In addition to the procedures listed in Section 1.1, trained personnel should inspect the SLS toes, carbon fiber leg tubes, and aluminum receiver of each four landing gear assemblies. It is important to look for carbon fiber or aluminum that is displaying signs of fracturing as this indicates a component failure. Additionally, no part associated with each leg should exhibit free movement where fasteners are installed to prevent it.

***Fully Electric owners should test the lock-out capabilities of folding landing gear and its roll pin.

Payload Support Inspection

In addition to the procedures listed in Section 1.1, trained personnel should inspect the aluminum clamps mounted to the flight control box, carbon fiber payload rails, and dampening plate. Carbon fiber or aluminum components that exhibit fracturing will be in need of replacement. Some areas to consider would be where the payload rails mount to the flight control box, to make sure the weight has not caused the carbon fiber to warp here. Each payload rail should be rigid and unmoving in the x-plane. Dampening plate polyurethane dampers should be fully seated in both the top and bottom of their respective plate and free of dry-rot or tearing.

***Clients with Gremsy quick release should ensure the tightness of their release is sufficient enough for mounted payload.

Upper Frame Inspection

The upper frame consists of two major assemblies, which include: the central airframe and the hinge and boom assembly. Inspection of each boom and hinge before every flight is critically important as this assembly provides the rigid structure that makes propulsion possible. Inspection of the central airframe before every flight is limited primarily to a few select components mounted on its surface. If in the event there is a component failure, ordering a replacement is recommended.

Hinge and Boom Inspection

In addition to the procedures listed in Section 1.1, trained personnel should inspect the hinge and its folding and locking capabilities, and the integrity of the boom arm. The hinge and boom arm should be free of fracturing. Check the seating of each boom arm in each hinge (near the wire inlet) and ensure the boom arm is flush with the base of the hinge. Additionally, when the boom and hinge are in the locked position check for free-movement in the z-plane, if there is movement present that exceeds ±2mm the hinge may require a new roll pin.

***The locking action of the hinge is the most important feature to consider when inspecting the upper frame assembly. When a hinge is in the locked position, it should not budge unless the release pin has been depressed. If for any reason the integrity of the locking mechanism of any one hinge is in question, all use of the aircraft should be ceased until the issue has been resolved.

Central Airframe Limited Inspection

In addition to the procedures listed in Section 1.1, trained personnel should inspect the plunger assembly and GPS stands. The plunger assembly serves as a latch that protects the 12S battery pack, canopy fuel tank, or hydrogen tank from coming loose during flight or transport. The movement of the plunger pin should be smooth and undeterred, refer to chapter 9 for instructions if adjustment is needed.

***The GPS stands should lock in place when upright, if a GPS location changes before or during flight, it may result in a failsafe.

Propulsion System Inspection

The propulsion systems consist of the two primary components responsible for the lift and three-dimensional movement of your aircraft: the motors and propellers. Inspection of these two areas before every flight is necessary to certify the aircraft is operating efficiently and to reduce the risk of personal injury or property damage. If a component failure occurs, ordering a replacement is recommended.

Motor Inspection

In addition to the procedures in Section 1.1, trained personnel should inspect the motor bell-housing and coils:

• Bell-housing: Fully extend the boom and open the propellers. Grasp the propellers near the central hub and attempt to rock the motor back and forth; if more than 0.5mm of play in the z-plane is discovered, the motor needs replacement.
• Motor Coils: Perform an individual motor test from a safe distance to ensure correct spin direction and rule out debris.
• Debris: Listen for grinding or rubbing sounds; these can usually be resolved by blowing out debris with an air compressor.
• Oxidation: Inspect coils for oxidation or char patterns, which may indicate a bad motor requiring replacement.

Thorough motor inspection prevents in-flight failure, vehicle damage, property damage, and injury.

Propeller Inspection

In addition to Section 1.1 procedures, trained personnel should inspect propeller blades, tips, and the central hub:

• Visual Inspection: Check each propeller for stress fractures along the blade, near the central hub, or chipping at the tips.
• Hardware: Ensure the nuts under the central hub have not loosened from their bolts; do not attempt to adjust these bolts.

Alignment: Periodically check blade tip alignment between propeller sets. Height or pitch differences can alter aircraft performance efficiency (further discussed in section 3.1).

Energy System Inspection

The energy systems consist of the battery storage, fuel, air, and spark systems that convert potential energy into kinetic energy. Inspection of each battery's integrity and cell health, fuel line and tank integrity, and generator or fuel cell integrity. If in the event there is a component failure, ordering a replacement is recommended.

Battery Inspection

In addition to the procedures listed in Section 1.1, trained personnel should inspect each Tattu 125 battery (Fully Electric users) or 6S Max Amp battery (EFI and Hydrone users). Using the included "Capacity Controller" or your charging station check the cell health for each cell, no cell should be ±200mV (0.2V) from another. Never fly with a battery that exhibits cell health depletion. Before flight, a battery should have at least 80% charge. If the casing or shell of a battery is damaged or the battery shows signs of swelling or is hot to the touch, cease use and dispose of the battery in accordance with your local ordinances.

Pre-Flight Battery Checklist

Pre-Flight Battery Checklist	Note
Check the cell health	Is there a noticeable difference (±0.2 V) between cell values? If so, the battery could be unhealthy.
Check for voltage imbalances	Is one battery capacity depleted more? Never operate a vehicle with a ±0.2 V difference between batteries.
Minimum Voltage Recommendation	For EFI and Hydrone users, it is recommended that the battery voltage is no lower than a combined 47.5 V (23.75 V each). For fully electric users, be aware a failsafe will occur at a combined voltage of 43.75 V.
Maximum Voltage	EFI and Hydrone users should avoid activating their generator or fuel cell with a combined battery voltage above 49.5 V.
Damaged or Swollen Battery	Cease using this battery, dispose of it properly.

Electrical & Communications Inspections

Connector and Antenna Inspection Guide

The electrical and communications systems include, but are not limited to, auxiliary and input power connections and telemetry connections. It is also necessary to verify that communication between the radio and flight controller is functioning correctly.

Connector Inspection

In addition to standard procedures, trained personnel using a multimeter should inspect the polarity and voltage output of various connections, especially after self-maintenance requiring their removal. All electrical testing should be performed by a technician familiar with multimeter equipment.

Connector	Location	Instructions
AS150U	Top Frame: Right Front, Left Rear	Continuity: Use a multimeter to check continuity between the black-tipped anti-spark brass connector and the positive PDB (right side). Repeat for the solid brass connector and the negative PDB (left side).
XT90 (EFI/Hydrone only)	Bottom Frame: Rear of Aircraft - Gen to PDB	Continuity: Use a multimeter to check continuity between the positive terminal of the male XT90 (second from left, under frame arm 6) and the positive PDB (right side). Repeat for the negative terminal and negative PDB (left side).
XT60	Flight Control Box: Auxiliary Power	Voltage: Use a multimeter to measure DC voltage with devices removed. Verify magnitude and polarity as labeled (e.g., 48V, 24V, 12V). Negative voltage indicates an internal short.
JST and JST-GH	Avionics Plate: Various	Visual: For JST, verify pin 1 is ground (black) and pin 2 is hot (red). For JST-GH, ensure they are seated in the Pixhawk or DC-DC converter and pins are secured in the housing.
Servo	Avionics Plate: Pixhawk Rail; Rear of Flight Control Box	Visual: Verify connectors are secure with the ground wire (black) facing up. On the Flight Control Box rear wall, incorrect polarity results in lost generator telemetry.

Coaxial Cable and Antenna Inspection

Trained personnel should inspect all applicable COAX connections, antennas, and related supports or housings.

Connection	Location	Notes
Coaxial Terminator	Various: Rear Legs, Booms 1 & 2, Booms 5 & 3, Flight Control Box	Check for damage (bent/crushed terminators) and remove debris. Verify each cable is secured with an 8mm lock and tooth washer.
Antenna	Various: Rear Legs, Booms 1 & 2, Booms 5 & 3, Flight Control Box	Verify the gender for each antenna is the opposite of its associated COAX terminator to avoid damage or loss of communication. Ensure the housing is not broken.

150–300 Hour General Inspection Guidelines

Battery Replacement (150 Hours)

The lifetime of a battery is dependent on a number of factors which include but are not limited to: how often the battery is charged, how it is used, and how it is stored. Over time the performance, or rather the capacity, of a lithium-polymer battery will begin to deplete and it will fail to hold a charge or charge.

***To reduce the risk of failure during flights, the recommended replacement cycle for batteries used in HA-UAS is after every 150 hours of use or when a considerable drop in performance is observed.

Max Amp 4750mAh Battery Removal

To remove a Max Amp 4750mAh battery, known also as generator backup batteries, simply loosen the two velcro straps that hold each battery onto the lower frame plates located beneath frame arm 1 and 2.

Tattu 16,000mAh 12S1P Battery Pack Removal and Disassembly

To remove Tattu 16,000mAh 12S1P battery pack, release each plunger on the top frame plate and lift the battery pack from the frame. A total of eight screws secure dovetails to the sides of the batteries, each requiring a 2.5mm hex driver to remove. Take note of each screw length and any spacers used as they will need to be replaced in the exact order for each replacement battery. Balance ports should face outward, if any one balance port faces the other battery the direction is incorrect and will need to be corrected.

Battery Replacement (150 Hours)

Generator Or Fuel Cell Removal & Installation (300 Hours)

Over time, the integrity of the generator's cylinder, piston, and seals will degrade and when this occurs a lack of compression may occur. As a result, the Löweheiser EFI generator has a recommended replacement lifetime of 300 hours. This is to ensure that both the generator and aircraft function and operate at their optimal performance. Similarly, Intelligent Energy fuel cells are subject to a degradation in performance over many hours, and thus, replacement is required after 300 hours.

Generator Removal and Installation

To remove a Löweheiser EFI generator, first remove the large clear and large yellow fuel lines from the fuel inlet and fuel return, unplug the telemetry cable which is inserted into the flight control box, and remove the four M3x8 socket screws located on each rail clamp. Be sure to support the generator while removing these screws, otherwise the generator may fall during removal. Use the same process detailed here, but in reverse order for replacement generators. Refer to Appendix A for torque specifications.

Fuel Cell Removal and Installation

To remove an Intelligent Energy fuel cell, first make sure to remove any gas lines that may still be connected to a hydrogen tank, unplug the telemetry cable which is inserted into the flight control box, and remove the four M3x8 socket screws located on each rail clamp. Be sure to support the generator while removing these screws, otherwise the generator may fall during removal. Use the same process detailed here, but in reverse order for replacement generators. Refer to Appendix A for torque specifications.

450–600 Hour General Inspection Guidelines

Motor Replacement (450 Hours) & Full Maintenance Inspection (600 Hours)

A T-Motor KV motor in simplest terms is a series of inductive coils of copper, wound tightly to allow current flow through it to create a magnetic field that reacts with the magnetic plating located inside of the motor bellhousing. These coils and plates are subject to degradation due to use and the environment which can lead to oxidation, corrosion, and buildup that can severely limit the functionality of the motor. As a result, the manufacturer's required replacement interval for each motor is 450 hours.

Motor Replacement

To remove each motor, first remove the propellers mounted to the top of each propeller, instructions for which can be found in section 4.1. Next, remove the mounting screws on both sides of the motor mount. Pull the motor gently off the boom, and allow the wires to come through the grommet. Attached will be an MR60 connector, unplug this connector to release the motor from the aircraft. If replacement is being done DIY, remove the motor mounts underneath each motor, and replace on the new motors. Detailed instructions for motor replacement can be found in section 8.

Full Maintenance Inspection

At every 600 hour interval a full maintenance inspection is recommended. What this entails is a thorough inspection of the aircraft and its structural, mechanical, electrical, and avionics systems, performed by a skilled HA technician.

Motor Replacement (450 Hours) & Full Maintenance Inspection (600 Hours)

600–1000 Hour General Inspection Guidelines

ESC Replacement (600 Hours) & Aircraft Analysis & Replacement (1000 Hours)

A T-Motor KV Electronic Speed Controller (ESC), is a linear control device that uses pulse-width modulation (PWM) inputs to determine how quickly a motor should spin in relation to the other motors. These ESCs play a crucial role in the aircraft's ability to hover and otherwise maneuver properly. The manufacturer recommends each ESC be replaced after 450 hours of use to prevent component or inefficient flight characteristics.

ESC Replacement

Removing ESCs on H6 requires extensive work due to the nature of the ESCs placement between the top and bottom frame plates. It is mandatory that all ESC replacements needed on H6E platforms be performed at our facility unless prior consent is given.

Any attempt by a client to replace ESCs themselves without prior consent will render the flight integrity of the airframe uncertifiable and will void warranty.

Aircraft Analysis and Replacement

Congratulations on reaching 1000 hours of operation with your aircraft. Depending on how quickly this milestone has been reached, there should be a few things to consider.

1. The age of each component, specifically those manufactured in house at HA. Our product is always improving, and because of this, so are the specifications and designs of key components that your aircraft consists of, these usually include:
   
   a. Carbon Fiber
   b. Aluminum: Hinges, Landing Gear, Standoffs, etc.
   c. 3D Printed or SLS Parts
   d. Frame Support Walls
   e. Electronics: Avionics, Navigation, etc.

2. The condition of the aircraft. If an aircraft has experienced repeated use, transport, and exposure to varying environmental conditions, many components housed within each aircraft may experience degradation.

Therefore, it is highly recommended that an aircraft be assessed after being used for 1000 hours or more. Replacement of obsolete frame hardware guarantees that your experience with HA aircraft is up to date with our most recent standards, tolerances, electronics, and software which also allows us to provide the best support we can in regard to your aircraft.

ESC Replacement (600 Hours) & Aircraft Analysis & Replacement (1000 Hours)

Landing Gear Disassembly & Reassembly Guide

Overview

Instructions for disassembling a landing gear assembly and preparing it for reassembly.

Tools Required

• 2.5mm hex screwdriver
• 8mm socket
• 5.5mm socket
• T10 screwdriver (for folding landing gear)
• #30 drill bit (1/8 inch or 3.26mm)

Disassembly Steps

1. Remove Attachments: Remove any antennas present. Use a 2.5mm hex screwdriver for the clamping screw and an 8mm socket for the locking hex nut.
2. Remove Leg Bracket: Remove the M4x14 socket screws (M4x16 for folding gear) from the leg bracket to detach the landing gear assembly. Ensure the aircraft is on a stable surface to prevent falling.
3. Remove Through-Bolt: Secure the M3 lock nut with a 5.5mm socket. Use a 2.5mm screwdriver (or T10 for folding gear) to remove the M3x35 through-bolt. Retain the M3 washers.
4. Release Carbon Fiber Leg: Loosen the M3x8 socket screws on the landing gear clamp to release the leg.
5. Remove Tube Toe Bolt: Secure the M3 lock nut with a 5.5mm socket and use a T10 screwdriver to remove the M3x35 through-bolt from the tube toe. Retain the M3 washers.

Reassembly Steps

1. Reverse Procedure: Follow the disassembly steps in reverse (from Step 5 back to Step 1).
2. Bore Out Slots: Use a #30 drill bit (3.26mm) to bore out a slot for the through-bolt at the tube toe and the landing gear receiver.

Assembly and Disassembly: Payload and Dampening Assembly

To disassemble the payload and dampening assembly, begin by unplugging any wiring that may be connected to a sensor, camera, or gimbal, the generator telemetry cable, and the generator and fuel lines.

Disassembly

• Step 1: Remove the M4x6 socket screws from the leg bracket to remove one landing gear assembly. Make sure the aircraft is placed on a surface that will prevent it from falling as legs are removed.
• Step 2: Remove all four M3x8 socket screws from each Gremsy clamp.
• Step 3: If maintenance is required on a Gremsy quick release, use a 1.5mm screwdriver to remove the quick release from the dampening plate.
• Step 4: If replacement of payload rails is required, use a 2.5mm screwdriver to remove the M3x22 socket screws from each payload clamp.

• EFI and Hydrone users: Payload rail tube caps should measure exactly 300mm from end to payload clamps when installed.
• Fully Electric users: This measurement should be exactly 25mm from end to payload clamp.

Reassembly

To reassemble a payload and dampening assembly, follow the disassembly procedure in reverse from Step 4 to Step 1.

Assembly and Disassembly: Booms, Motors, and Propellers

Assembly and disassembly of the booms, motors, and propellers require additional considerations in regard to the overall balance of the propulsion system. This section discusses procedures related to disassembly, reassembly, and balancing in detail.

Disassembly - Propellers and Motors

• Step 1: Remove the four Black T-Motor M4 screws securing the propeller to the motor frame and remove the propeller. Take note of the propeller blade orientation for reassembly (refer to the diagram on page 29).
• Step 2: Remove the boom covers (with LEDs and/or antennas). Loosen the M3x8 torx screws located at the end of each boom and remove the cover enough to access the interior.
• Step 3: Loosen the four screws securing the motor mount to the boom. Remove the motor mount bracket located inside the boom, as it is needed for reinstallation. Carefully pull the motor and wires through the grommet until the MR60 connector is accessible, then unplug the motor.
• Step 4: To replace the motor, remove the motor mount by loosening the four M4x10 torx screws. Loosen each screw two turns at a time until the motor mount is free.

Reassembly - Propellers and Motors

Reassembly should be performed in reverse order, from Step 4 to Step 1.

• Alignment: Align the motor mounting brackets with the fileted edge facing upward into the shape of the boom.
• Fastening: Motor-to-boom mounting screws should not be loctited during this process to allow for maneuverability during the balance process.

Disassembly - Booms & Hinges

In rare cases, boom and hinge assemblies may require replacement. Due to a number of factors which may affect the flight characteristics, replacement of these assemblies by an experienced HA technician is strongly advised; these factors include, but are not limited to: frame balance, arm balance, and boom balance.

Doing so without prior consultation will void your warranty. It is recommended that if boom or hinge damage is present, the aircraft be sent in to our facility for repairs.

• Step 1: In the event booms need to be removed, first follow the procedures listed on the previous page regarding propeller and motor disassembly.
• Step 2: Next, remove the hardware securing the boom to the hinge, including: the hinge through-bolt, the hinge clamp bolts, and loosen the set screws on top of the hinge. The boom arm should now be free to remove from the hinge assembly.
• Step 3: To remove the hinges, the aircraft should be placed on a surface capable of supporting the frame from underneath which allows the legs to be removed. Each leg is secured with four socket screws, and removal is required to access certain hinges. Each hinge is secured with eight M4 torx screws located on the top and bottom frame plates. Take note of the landing gear bracket (a T-shaped piece of aluminum) orientation for reinstallation.

Reassembly - Booms & Hinges

• Step 1: Replacing hinges requires additional consideration for the balance of each frame arm; a dial indicator is recommended for accuracy. While reinstalling hinges, leave all eight screws loose and raise or lower the hinge while tightening each screw in a cross pattern. Use the dial indicator to measure the alignment of the inner frame to the end of the frame arm until the tolerance is no greater than ±0.005mm.
• Step 2: Replacement booms require a .118 (3mm) drill bit to bore out the left and right side of the boom. This should only be performed once all other hardware is installed and the boom is seated. Ensure the boom makes contact with the back of the hinge receiver (inspect via port holes). To balance, use a meter stick level to align with adjacent and opposite booms, then reinstall and torque clamp bolts in sequence three times.
• Step 3: Once booms are installed, balanced, and secured, reinstall set screws at the top of the hinge until they make contact with the carbon fiber. Finally, reinstall the through-bolt and its associated hardware (M3 washers, M3 locknut).

Balancing - Propellers and Motors

Balancing motor and propellers allows the propulsion system on HA aircraft to maintain efficiency while in flight, and prevents the accelerometer from having to make unnecessary adjustments for maintaining position. Balancing will require a small ruler level, a leveled surface, and patience. Balancing can be done with the propeller on or off, but to achieve the most accurate results, it's recommended that the propeller is off.

Step 1: With the motor mount screws slightly loose, small incremental adjustments will be made to the motor using an X and Y-plane reference. The X-plane (perpendicular) is controlled by the front two screws, while the Y-plane (parallel) is controlled by the rear two screws. In order to properly adjust the Y-plane, the X-plane must be set first and torqued in place, otherwise Y-plane adjustments are prevented. Place the level on top of the motor and determine which direction the motor will need to move in both directions (X and Y).

Step 2: Slowly begin tightening the X-plane screws while tilting the motor in the desired direction. Be careful not to crush the motor grates while making adjustments. Some overshoot may be required during adjustment to compensate for the torque of the materials acting in the opposing direction. When a balance on the X-plane of ±0.005mm is achieved, torque both X-plane screws in place.

Step 3: With the X-plane locked, place the level parallel to the boom, and begin adjusting the Y-plane using the same process as step 2. There is a chance that the X-plane will shift while adjusting the Y-plane if the required adjustment is large. In this case, steps 2 and 3 may require repetition several times until the desired balance is achieved.

Step 4: Once all motors have been balanced, it is recommended that a final balance check be performed with the propellers. To do this, install each propeller and fully extend the blades. Compare the tip of one blade to the adjacent propeller. Propeller tips should align flush with each other, have little to no angle, and be within ±0.01 of each other vertically. If propeller alignment is not ideal, balance procedures for booms listed on the previous page, and those listed on this page should be repeated until the desired balance is achieved.

Step 5: With all motors and propellers aligned, remove ONE screw from the motor mount at a time, loctite it, and replace it. Repeat this process for each screw that may have been adjusted during balance, which includes those associated with booms, motors, and propellers.

GP Assembly & Disassembly

To disassemble a GPS assembly (stand and puck), clip the zip-ties securing the CAN cable to the side of the aluminum stand, and disconnect the CAN cable from its respective port inside the aircraft (CAN Bus for GPS right, Pixhawk CAN2 port for GPS left).

Disassembly

• Step 1: To remove the GPS puck, remove the M2.5x8 screw from the rear of the GPS puck and slide the puck off of the mount. Using a 1.0mm wedge or pry tool, remove the lid of the GPS puck. Disconnect the CAN cable from CAN port 1.
• Step 2: To remove the GPS mount from the extension, remove the two M3x8 flat torx screws securing the mount to the top of the extension.
• Step 3: To remove the GPS extension from the GPS stand, use a long M3 (T10) to remove the M3x12 flat torx screw from the center of the extension.
• Step 4: To remove the GPS stand from the frame, use a 2.5mm screwdriver to remove the M3x10 and M3x8 socket screws from the base of the stand, while holding the bracket that resides beneath it.
• Step 5: If removing/replacing CAN cables, cables should be routed through the interior wall section located at frame arm 1 and/or 2. The right GPS is typically routed to the CAN bus that is located at the front of the aircraft, inside the central airframe.

Reassembly

To reassemble a GPS assembly, follow the disassembly procedure in reverse from Step 5 to Step 1. While performing Step 4 the GPS stand bracket must be used to secure the stand in place.

Assembly and disassembly of the booms, motors, and propellers require additional considerations in regard to the overall balance of the propulsion system. In this section, procedures related to disassembly, reassembly, and balancing will be discussed in detail.

Disassembly - Propellers and Motors

• Step 1: Begin by removing the four Black T-Motor M4 screws securing the propeller to the motor frame, and remove the propeller. Take note of the propeller blade orientation, as this will be important for reassembly. A diagram illustrating blade orientation can be found on page 29.
• Step 2: Next, remove the boom covers (with LEDs and/or antennas). The screws (M3x8 torx) for each are located at the end of each boom. Once loosened, remove the boom cover enough to gain access to the interior of the boom.
• Step 3: Each pair of screws securing the motor mount to the boom is fastened into a motor mount bracket located on the inside of each boom. When loosening the four screws that secure the motor mount to the boom, be sure to remove this bracket as it will be needed for reinstallation. With the motor mounts loose, carefully pull the motor and its wires through the grommet until the MR60 connector is accessible, and unplug the motor from it.
• Step 4: To replace the motor, the motor mount will need to be removed and replaced onto the new motor. The motor mount is secured with four M4x10 torx screws that require incremental adjustments. Carefully, loosen one screw two turns at a time until the motor mount is free.

Reassembly - Propellers and Motors

Reassembly of the motors and propellers should be performed in order from Step 4 to Step 1. Be sure to align the motor mounting brackets with the fileted edge facing upward into the shape of the boom. Motor to boom mounting screws should not be loctited during this process, as this will limit the maneuverability of the motor during the balance process.

Disassembly - Plunger and Rack Alignment Assembly

To begin, remove the SLS E-Box walls and the avionics cover plate.

• Step 1: Remove the four M3x8 socket screws at each corner of the interior basin.
• Step 2: Lift the avionics cover plate out of the aircraft.
• Step 3: Press the E-Box wall inward near the rack alignment wall to release the opposite side and pull the SLS wall out.
• Step 4: Remove the six M3x12 flat torx screws (marked orange in Figure 29) and the mounting bracket to remove the rack alignment wall.
• Step 5: Remove the single M3x12 flat torx screw at the rear of the plunger handle, along with the brass plunger pin and spring.
• Step 6: Remove the two M3x12 flat torx screws at the rear of the plunger base and its mounting bracket.

Reassembly - Plunger and Rack Alignment Assembly

Reassembly should be performed in reverse order, from Step 6 to Step 1.

• Mounting Brackets: Pay close attention to the installation of brackets for the plunger base and rack alignment wall.
• Plunger Base Brace: Use the bracket with two slots for M3 square nuts as a brace for the plunger base.
• Tech Tip: It is recommended to loosen the PDBs to slide the plunger base brace into place.

12S Battery Rack Assembly

To assemble the 12S battery rack, it is recommended that a level surface is used to prevent the batteries from becoming misaligned or bowing.

Disassembly - 12S Battery Rack Assembly

• Step 1: First, remove the four socket screws located at the top and bottom of each dovetail bracket.
• Note: Two screws will have a plastic dowel used as a brace between the dovetail bracket and the battery housing; take note of the orientation that the dovetail bracket is installed for proper reassembly.
• Step 2: With the dovetails removed, begin loosening the flat torx screws securing the dovetail to the dovetail plate.
• Note: There are a total of six screws per plate.

Reassembly - 12S Battery Rack Assembly

• Step 1: To reassemble a 12S battery rack, first align the dovetail with a dovetail plate, paying particular attention to the shape of the plate in reference to the dovetail.
• Reference: Use Figure 30 as a reference if needed.
• Note: If new dovetails are being used, M3 lock nuts will need to be inserted into the slots of the exterior of the dovetail before it can be secured to a plate.
• Step 2: On a level surface, place two 12S batteries in the orientation shown in Figure 30 with the Tattu logo on the broadside facing inward.
• Alignment: Place a dovetail bracket alongside both batteries, and align it with each battery.
• Dowel Placement: Insert a plastic dowel between the battery and plate for the top and bottom of the right-hand battery.
• Securing: Install all four screws and tighten each until the bracket is secured.
• Caution: While installing the second bracket, be sure to prevent any misalignment between the batteries.
• Correction: If a battery is misaligned, it will appear crooked on the level surface. Simply loosen each of the corner screws and tighten them once more.