Suggestions for taking off in parking lot / pier

[FASTFJR]

I want to shoot our cruise ship in Aruba in about a month. I've always been very leery about taking off from a parking lot / pier especially when its made from concrete / rebar. I never fly when when my compass calibration is in question or when I don't have at least 10-12 satellites

In this situation does anyone have any suggestions? I was thinking maybe holding the Mavic is the air on start up and doing a hand launch? I've never attempted either one, not even sure it could be done

Thanks

 

[lisadoc]

Are you taking it with you on your cruise? I don't know any cruise ships that start from Aruba so I'm assuming you're talking about taking it aboard with you. Be careful, as most cruise lines will confiscate your drone when you embark (if they find it) and won't return it to you until the end of the cruise.

As for your answer, hand launching will work. However, I wouldn't assume that the parking lot (or anywhere for that matter) will automatically give you compass problems. You can start it up and see if you get a compass error. If not, you're good to go. If so, you can always move it or hand launch. But if the Mavic says it's fine, there's no need to worry about a compass error.

 

[sar104]

You could either use a magnetometer app on your phone to check for magnetic distortion or use @BudWalker's much simpler suggestion just to check before launch that the aircraft magnetic heading (the arrow on the map) agrees with the direction that it is actually facing. That way you should be able to find somewhere good to take off.

 

[sar104]

Are you taking it with you on your cruise? I don't know any cruise ships that start from Aruba so I'm assuming you're talking about taking it aboard with you. Be careful, as most cruise lines will confiscate your drone when you embark (if they find it) and won't return it to you until the end of the cruise.

As for your answer, hand launching will work. However, I wouldn't assume that the parking lot (or anywhere for that matter) will automatically give you compass problems. You can start it up and see if you get a compass error. If not, you're good to go. If so, you can always move it or hand launch. But if the Mavic says it's fine, there's no need to worry about a compass error.

Just the absence of a compass error before launch is not a good indication that the location will work.

 

[lisadoc]

Just the absence of a compass error before launch is not a good indication that the location will work.

I'm not sure I get this. Could you elaborate?

 

[sar104]

I'm not sure I get this. Could you elaborate?

When you set the Mavic on the ground and power it up, all it measures is the local magnetic field vector, which will be a linear superposition of the earth's field plus any other local fields. Unless the measured field is unreasonable (e.g. inclination is vertical), it cannot know whether it is seeing just the earth's field or a modified field, since it has no other directional reference. So, it will trust the computed magnetic heading and use that to initialize the IMU reference heading, and it may not discover until after take off that the reference heading was wrong, at which point compass and IMU will diverge and the usual problems start.

 

[Aerial-Pixel]

I'm not sure I get this. Could you elaborate?

If you go to the location and go to lift-off and there is no compass error shown you should be fine. If you see any errors like "Strong Magnetic Interference" simply move to another location.

 

[Youser]

Are you taking it with you on your cruise? I don't know any cruise ships that start from Aruba so I'm assuming you're talking about taking it aboard with you. Be careful, as most cruise lines will confiscate your drone when you embark (if they find it) and won't return it to you until the end of the cruise.

As for your answer, hand launching will work. However, I wouldn't assume that the parking lot (or anywhere for that matter) will automatically give you compass problems. You can start it up and see if you get a compass error. If not, you're good to go. If so, you can always move it or hand launch. But if the Mavic says it's fine, there's no need to worry about a compass error.

I always wanted to know if a hand launch helps with compass errors where you think there might be some.

 

[sar104]

If you go to the location and go to lift-off and there is no compass error shown you should be fine. If you see any errors like "Strong Magnetic Interference" simply move to another location.

No - I disagree. We have seen enough logs on these forums showing compass and yaw errors that do not start until significantly into the flight to know that this is a necessary, but not sufficient, test.

 

[sar104]

I always wanted to know if a hand launch helps with compass errors where you think there might be some.

If you are holding it high enough to be clear of the magnetic distortion then it will help with that problem. Better, in my opinion, simply to find a location free of distortion before launching.

 

[Hauptmann]

I've taken off from piers with no problems whatsoever. Concrete structures, yes and no.

When taking off from reinforced concrete or near a lot of steel, make sure you're in GPS mode. If you're in ATTI mode at takeoff, you MAY have a mag field issue. If so, hover at 3-5' briefly until it resets to GPS mode. If flying at night, use distinctive lights (Cree or otherwise) so you will know visually the location of your bird in case something goes awry. I'm no scientist, but it has worked for me.

But as Aerial-Pixel stated above, If you see any errors like "Strong Magnetic Interference..." you'd be safer moving to another location.

 

[BudWalker]

If you go to the location and go to lift-off and there is no compass error shown you should be fine. If you see any errors like "Strong Magnetic Interference" simply move to another location.

It's not sufficient to just rely on the AC to tell you if there is a compass error. There have been many fly away type incidents caused by a compass problem, yet there was no indication prior to launch. Here are a few examples

Compass error

And, this one seems to be popular
Looking for Trouble ??

The single most effective way to prevent this is to confirm the Go App red triangle heading indicator is pointed correctly prior to launch.

 

[FASTFJR]

Are you taking it with you on your cruise? I don't know any cruise ships that start from Aruba so I'm assuming you're talking about taking it aboard with you. Be careful, as most cruise lines will confiscate your drone when you embark (if they find it) and won't return it to you until the end of the cruise.

As for your answer, hand launching will work. However, I wouldn't assume that the parking lot (or anywhere for that matter) will automatically give you compass problems. You can start it up and see if you get a compass error. If not, you're good to go. If so, you can always move it or hand launch. But if the Mavic says it's fine, there's no need to worry about a compass error.

Thanks guys! All good info

Cruise is leaving out of NYC, 14 day Southern Caribbean. I've know three others who have taken their drones on this same cruise line in the last 6 months. All made it on the ship without any issues, two had them "Stored" when coming back on from the first port, they were found with the X Ray machines. However all they had to do at the next port was asked for it back and they returned it to security when coming back on the ship. One never had any issues at all. I hoping with all the other camera gear in my backpack they won't even notice it. I do plan to separate everything when we pack. The cruise lines just don't want some idiot flying OFF the ship, their have been a few I've seen the YT videos. My favorite was the idiot who wasn't able to fly it back fast enough and it crashed in the ocean Lol

Will see how it goes, if I'm caught I'm caught, not a huge deal as long as they store it ok.

 

[lisadoc]

It's not sufficient to just rely on the AC to tell you if there is a compass error. There have been many fly away type incidents caused by a compass problem, yet there was no indication prior to launch. Here are a few examples
Compass error

Prior to launch is the issue. However, if you take off to 5 feet or so, hover a bit, and receive no compass errors or switch into ATTI, then there shouldn't be an issue. All of the examples I have seen are when the AC shows compass issues shortly after taking off, not long after takeoff and well into flight. The two examples you gave were just that as well - compass errors immediately after takeoff.

 

[BudWalker]

Prior to launch is the issue. However, if you take off to 5 feet or so, hover a bit, and receive no compass errors or switch into ATTI, then there shouldn't be an issue. All of the examples I have seen are when the AC shows compass issues shortly after taking off, not long after takeoff and well into flight. The two examples you gave were just that as well - compass errors immediately after takeoff.

You're right those flights were from a P3 which behaves differently than a Mavic. A P3 will declare a compass error and switch to ATTI when it sees a difference between heading derived from IMU measurements and heading derived from the magnetometers.

But the Mavic, as well as the other platforms after the P3, will often remain in ATTI without declaring a compass error and attempt to reconcile the problem. It does this by holding the Yaw value constant while it rotates until the compass agrees with that constant Yaw value. Sometimes this works, sometimes not as in this incident

2 Fly Aways - Log Help

There was never any warning or switch to ATTI but clearly the compass was compromised resulting in erratic flight and a crash that broke two props. By looking at the totalGyro:Z it can be seen that the Mavic was rotating as described above. The only way to know this was going to happen would have been to check the heading indicator on the Go App map.

I'm assuming that hovering for a bit at 5 feet is an attempt to see if there is a compass problem before beginning the flight. But, this could be a problem because if Yaw is compromised it could still cause a fly away during the hovering phase. The FC is still making corrections, although small, because of noise and external inputs like wind. Any correction would be in the wrong direction causing an even larger subsequent correction in the wrong direction. I think that's what happened in this flight. There were no stick inputs prior to 4.5 secs but the Mavic had moved 0.7 meters from the HP.

 

[FASTFJR]

Thanks again for the info and insight. I will plan to hand launch if their is any question

 

[Lake_Flyer]

Thanks again for the info and insight. I will plan to hand launch if their is any question

Switch off the landing protection, it makes it a lot easier and safer should you need to catch it as well. Taking off from your hand is easiest using Auto Take off.

 

[FASTFJR]

Switch off the landing protection, it makes it a lot easier and safer should you need to catch it as well. Taking off from your hand is easiest using Auto Take off.

Good idea, I need to practice that. I've never done it with the Mavic yet, I always hand caught my Phantoms

 

[BudWalker]

Thanks again for the info and insight. I will plan to hand launch if their is any question

That would probably help. In most of these types of incidents the geomagnetic distortion only extends 1 meter or less.

But, you can still run into a problem if you have powered on the AC while in the presence of any geomagnetic distortion. The Yaw value doesn't get corrected immediately. Depending on the platform, magnitude of the error, etc it can take between 10 secs to more than 30 secs for the Yaw to get fully corrected. If the hand launch occurs before Yaw has become correct then there could be a problem.

Just look at the red triangle heading indicator in the Go App (or any other app) to make sure it's consistent with the actual AC heading.

 

[Theali]

I was in and out of the Aruba cruise ship dock area in May/June last year (I work on survey boats). Didn't have mavic with me but I did notice that the wind was a fairly constant 30-40kmh all the time I was there, blowing to the south (out to sea). So something to keep an eye on. Also, the marine police HQ is about 50m from the quayside you'll be docking at, and security is pretty tight around the port. They may have something to say about flying around the area if you're spotted, although the island in general is super-chill so I'd be surprised if they did more than come over and ask you to stop if they do object.
You'll also be just a couple of kilometres from the airport.

If you come out of the port and turn left (heading northwest, opposite direction to airport), walk about a half hour up the road you'll find Eagle Beach which is gorgeous and some very pretty hotels. It's like a mini Vegas around there. That would be my pick for some quick and easy flying.

Toward the centre of the island there's a national park with a mountain/volcano thing in the middle of it. Great flying opportunity, but you'd need to rent a vehicle to get there.

Best place to eat/drink by far is here in the town centre.
Flor de Oriente
Google Maps
Not least because of the friendly waitresses. And I DO mean friendly!!

English/Dutch/Spanish is widely spoken by the locals. The locals also speak "Papiamento" unique to the island. Download an app, learn a couple of fun phrases to use and you'll do well.

Aruba is amazing. I'm so going back one day.
Have fun.