Mini 3 Pro Fly Away After Signal Loss

[istj]

Hi guys, I was flying my Mini 3 pro at night in a highly urban Area (Jakarta). It had already lost signal to the controller and then started to return to home automatically. It regained signal for a second and the last thing I saw was a tall building in front of it (about 80m away). It then lost signal again and never returned home. RTH altitude was set to 150m, but it appears the building was approx 230m in height. I had obstacle bypass enabled and was flying in Normal Mode.

What is likely to have happened? I searched the area below (some bushland) in case it had stayed in that position and landed, but no luck. I then thought that perhaps after it lost signal it kept trying to return home, but maybe crashed into the building due to lack of obstacle avoidance at night (being too dark). The building is under construction so I asked a few construction workers if they would mind looking on the ground and also around the top floors where it may have flown into. Nothing found yet. Unfortunately, I was not able to locate it with the controller using the flashing lights and beeps (so the battery was dead).

What is the most likely scenario in this case? Would it have crashed into the building due to insufficient light for obstacle avoidance, or would it have stayed where it was on the last known location and then eventually landed when the battery was dead?

Here is the flight log: DJI Flight Log Viewer - PhantomHelp.com

Last view of screen on the controller:

 

[GFields]

I'm not the expert but it looks like the obstacle avoidance wasn't working due to low ambient light. @Meta4 can tell you more about this.

 

[LoudThunder]

Perhaps the OA saw through the glass and before it recognized an obstacle, it hit a glass window or as has already been mentioned it does not work at night as it flew into a dark side of the building.

So, the lesson here is to set your RTH height higher that all obstacles and not let the excitement of the moment overtake you.

 

[Meta4]

What is the most likely scenario in this case? Would it have crashed into the building due to insufficient light for obstacle avoidance, or would it have stayed where it was on the last known location and then eventually landed when the battery was dead?

Signal lost at 5:16.6
When signal regained 6.5 seconds later, the drone was in RTH
Signal lost again at 5:24.4 and regained 21 seconds later.
Signal finally lost at 5:38.8 with the drone in stable flight at 10.5 metres/sec

Two buildings higher than the drone's height were directly in the RTH path.
The buildings were significantly higher than RTH height which was set for 148 metres.

Signal was lost because the tall buildings were between the user and the drone.
If RTH Height was set high enough to clear the obstacles on the RTH path, the drone would have come home safely.
Because RTH Height was lower than the obstacles, Obstacle Avoidance is the only thing that might prevent collision with the buildings.

But ...
The flight data has several warnings that lighting was not sufficient for obstacle avoidance to work.
Glass and reflective surfaces can confuse obstacle avoidance even in good lighting.

With no data to show what happened after final signal loss, we can only guess what happened.
Collision with the building is the most likely outcome in the circumstances.

 

[MAvic_South_Oz]

Wow, such a bad first post to make, but hopefully someone can give you some insight into where you might start to look, and what might have happened.

I just saw Meta4s reply above and concur.

Is this your first drone ?
It was a VERY risky flight to make, 1.5km distant, at night, heavy urban environment (buildings and signal interruptions), flying very low most of the time (bad for signal at the best of times), and all without really scoping out what you might encounter.

A good lesson for keeping VLOS, respectable distance, and learn in the right environment (daylight and open).

Keep checking with the construction crew on that first major building (Indonesia 1 of the twin towers) . . . there is a slim possibility it might have hit tower 2, but #1 looks like the best bet.

Good luck.

 

[istj]

Signal lost at 5:16.6
When signal regained 6.5 seconds later, the drone was in RTH
Signal lost again at 5:24.4 and regained 21 seconds later.
Signal finally lost at 5:38.8 with the drone in stable flight at 10.5 metres/sec

Two buildings higher than the drone's height were directly in the RTH path.
The buildings were significantly higher than RTH height which was set for 148 metres.

Signal was lost because the tall buildings were between the user and the drone.
If RTH Height was set high enough to clear the obstacles on the RTH path, the drone would have come home safely.
Because RTH Height was lower than the obstacles, Obstacle Avoidance is the only thing that might prevent collision with the buildings.

But ...
The flight data has several warnings that lighting was not sufficient for obstacle avoidance to work.
Glass and reflective surfaces can confuse obstacle avoidance even in good lighting.

With no data to show what happened after final signal loss, we can only guess what happened.
Collision with the building is the most likely outcome in the circumstances.

Thanks mate, just as I suspected

 

[istj]

Wow, such a bad first post to make, but hopefully someone can give you some insight into where you might start to look, and what might have happened.

I just saw Meta4s reply above and concur.

Is this your first drone ?
It was a VERY risky flight to make, 1.5km distant, at night, heavy urban environment (buildings and signal interruptions), flying very low most of the time (bad for signal at the best of times), and all without really scoping out what you might encounter.

A good lesson for keeping VLOS, respectable distance, and learn in the right environment (daylight and open).

Keep checking with the construction crew on that first major building (Indonesia 1 of the twin towers) . . . there is a slim possibility it might have hit tower 2, but #1 looks like the best bet.

Good luck.

Second drone actually, I lost my first drone (Mini 2) in manila.... also on a tower that was under construction and was never found. But in that case I had VLOS during the day... there was a gust of wind that blew it into the building. Seems urban flying is quite risky.

Yeah, you're right. I gotta stop doing such risky flights, especially in urban environments. Lesson learned.

 

[SkyeHigh]

Second drone actually, I lost my first drone (Mini 2) in manila.... also on a tower that was under construction and was never found. But in that case I had VLOS during the day... there was a gust of wind that blew it into the building. Seems urban flying is quite risky.

Yeah, you're right. I gotta stop doing such risky flights, especially in urban environments. Lesson learned.

Did you check drone flying regulations before hand? Although it is legal to fly for recreational purposes in Indonesia there are rules in place as in most countries.

• Drones may not fly above 150 meters (492 feet) without permission.
• Drones may not weight more than 7 kilograms (15.4 pounds).
• Drones may not be flown within 15 kilometers (9.32 miles) of any airport.
• Drones may not be flown over crowds or highly populated areas.
• Drones may not be flown at night.
• Drones may not be flown from any moving vehicle.
• Drone pilots must maintain a direct line of visual sight while flying.
• Penalties for non-compliance with these regulations are stiff, and include jail time and possible fines of up to 66,000 Euros.

 

[TonyPHX]

Did you check drone flying regulations before hand? Although it is legal to fly for recreational purposes in Indonesia there are rules in place as in most countries.

• Drones may not fly above 150 meters (492 feet) without permission.
• Drones may not weight more than 7 kilograms (15.4 pounds).
• Drones may not be flown within 15 kilometers (9.32 miles) of any airport.
• Drones may not be flown over crowds or highly populated areas.
• Drones may not be flown at night.
• Drones may not be flown from any moving vehicle.
• Drone pilots must maintain a direct line of visual sight while flying.
• Penalties for non-compliance with these regulations are stiff, and include jail time and possible fines of up to 66,000 Euros.

So this was not what they would call a "legal" flight from what it looks like.