C-Astral Bramor

 Introduction

The Bramor platform is a catapult launch and parachute landing UAS. It has an endurance of nearly 3 hours. Purdue has 2 versions of the platform, one has an Altum sensor the other has a Sony Alpha 6000 camera. Both platforms tie their data into PPK (post-processing kinematics) to allow for corrections without the need for ground control points. For learning these platforms we went through a variety of steps as they are complex aircraft. We began with learning how to fold the parachute, then going through the checklist and setting up the aircraft, as well as learning their software for developing flight plans. 

Parachute Folding

Folding the parachute properly is critical to the operation of the Bramor as it is its method of landing. The PowerPoint describes the folding of the parachute to aid in a visual representation of the aircraft manual.  

Checklist

The setup process if this aircraft can best be described as a dance, with both personnel working in tandem the aircraft is quickly set up and ready to go, but if they aren't able to work effectively together then there is a lot of tripping over each other, and possibility for missed steps. 

C3P

Mission One Settings:

• Draw an area over Purdue Wildlife Area

o Place your home, take off, rally/landing area in the open field area in SE corner.

o Make sure you initialize your sensors. (this relates to altitude settings)

o Set altitude to Relative to Terrain (bottom right corner)

o Set your Altitude to 125 meters

o Set to 80% frontal overlap and 75% sidelap (lateral)

o Set the Camera to the RX1R II 35mm

o Set the overshoot to 150m

Figure 1. C3P overview of a mission made per the following constraints, Altitude 125 meters, Overlap 80%, 75% sidelap, Sensor RX1R II 35mm, overshoot 150m

Mission 2 Settings:

o Set altitude to Relative to Terrain (bottom right corner)

o Set your GSD to 2.5 cm/pixel

o Set to 80% frontal overlap and 75% sidelap (lateral)

o Set the Camera to the RX1R II 35mm

o Set the overshoot to 120m

Figure 2: C3P overview of a mission made per constraints, GSD 2.5cm / pixel, 80% overlap, 75% sidelap, Sensor RX1R II 35mm, Overshoot 120m

Mission 3 Settings:

o Altitude 300m / Relative Altitude Mode.

o Overlap 80%, Sidelap 75%

o Overshoot 100m

o Selected Camera RX1R

• Set your Home, Takeoff, Rally, and Landing areas approximate to Figure 2. 

• Start by Doing a Sensor Initialize.

o In the upper right click on the wind icon and change the value to 5 m/s (about 11 mph/10 knots).

o Then change the heading to 300 degrees (N/NW wind).

Figure 3: C3P mission resultant of adding a 5 m/s wind from 300 degrees, added a parachute pop location marked P and an estimated landing area marked L with a purple spread of possible locations of touchdown.

Once the wind settings are input, a point marked P, where the parachute will be deployed and an area marked in purple, indicating the potential area that the aircraft will land.

Now the wind heading changed to 194 and the speed changed to 10 m/s.

Figure 4: C3P mission resultant of adding a 10 m/s wind from 194 degrees, added a parachute pop location marked P and an estimated landing area marked L with a purple spread of possible locations of touchdown.

Then the wind speed was decreased to 6 m/s and maintained its 194-degree heading

Figure 5: C3P mission resultant of adding a 6 m/s wind from 194 degrees, added a parachute pop location marked P and an estimated landing area marked L with a purple spread of possible locations of touchdown.

Figure 6: Mission summary for flight simulated in C3P mission planner.

Figure 7: C3P overview after completing the mission, note gray rectangles are estimated area captured by the photos.

Conclusion

Mission planning essentials involves ensuring that every aspect from weather to flight location, airspace, and obstacles, legal and physical are overcome to provide a successful outcome. This involves pre-mission planning prior to getting to the site. This planning usually involves studying the site in GIS-based software, looking for possible hazards such as powerlines or towers. This is also a time to plan out key locations such as home point, catapult location, take-off circle, landing area, and backups to these areas depending on wind direction. Generally, you can use the prevailing winds to identify these locations, but the winds could vary on the day that the mission is being flown. The goal of the mission planning in the office is to make sure that there is no need for second-guessing in the field, as various pressures, such as time constraints or clients can make the operation more stressful. Ensuring backup plans keep from needing a frantic re-planning while out in the field with a potential to miss some important steps.

This leads to the importance of the checklist. The pre-flight checklist is very important, as you do not want to end up with a Bramor in the air without a parachute in the bay. While that is an extreme example, from experience, sensor operators who did not use a checklist, left a lens cap on the camera, and it was the only gap in the clouds long enough to fly the field with a hyperspectral camera that day. We spent both Saturday and Sunday trying to capture that data again.

That situation would have been prevented if there was a checklist followed every time that payload was operated. Also, not everything can be verified from the office, so a preflight checklist keeps the pilot honest. It's possible that when the site was planned out in the office, a nearby construction operation did not know about so when the pilots got out to the field there was a crane in the area that was being overflown. Making sure that you truly go through each step in the preflight ensures the best outcome of the mission possible.

For the bramor, there are limited options for overriding. The pilot has just a few options for the aircraft while during the flight, first is the rally, which redirects the aircraft to the rally circle, and it loiters there. The second is loiter in which the aircraft will circle about its current location. The third would be to direct the aircraft to land and the fourth is to pop the parachute. You can also override the altitude and speed of the aircraft. I do not consider the “manual” mode an appropriate action to take in the event an override needs to happen, as it would be far too slow of a correction, but it allows you to control the direction of the aircraft to a limited extent.

Here is when I would take the following actions during a flight. 

Loiter: Let us say the pilot is flying out at PWA and the VO spots people hiking in the direction the Bramor is flying. This would be a good time to use loiter as keeping the aircraft from flying over people and breaking an FAA regulation is important. The aircraft can circle its current area to ensure it does not fly over the people and it can continue the mission once they are out of the way.

RTH: Let us say the Comms signal drops a lot suddenly. The best immediate action would be RTH as the aircraft would come back to the home point, which is likely where the PIC and GCS are. Bringing the aircraft towards the pilot and the GCS should increase the signal, and further discussion can happen to figure out the corrective actions for the rest of the operation.

Rally: Let us say that the aircraft had a battery voltage drop at an accelerated rate. This could mean that the battery has puffed beyond a safe operational point, or a cell has died. Either way, it is time to get the aircraft down and land, this one is a pilot discretion case as depending on the severity of the voltage drop it could be straight to popping the chute, but most likely the aircraft running 2 batteries in parallel should be able to land.

• Now speculate upon and provide examples of when and if one might need to manually pop the parachute.

Parachute pop is for extreme cases, wing separation prop failure, spins, and other situations where there is an imminent crash. Any time it would be appropriate to pull CAPS (Cirrus airframe parachute system), it would be proper to pop the chute. I would say that imminent danger to the aircraft, people, or structures, with all other options exhausted, is best practice for when it would be the proper time to deploy the chute as a last-ditch attempt.