Fog issues and lesson learned

[Maviac]

This may have been covered (I saw some posts anecdotally touching on it but nothing directly addressing it) so I wanted to share my experience.

I was recently out flying with my relatively new Air (about 10 hours flight time). I was about 3/4 mile from home, flying over farmland. Visibility wasn't great, but I could maintain VLOS. AWOS at the airport 10 miles away showed a ceiling at 1500' AGL. There were also patches of fog around, but I managed to stay well away from them. At some point, I lost the signal. Not a huge concern, as it had a clear route home, and even worst-case scenario, I could run and get it (to give away the ending, that's what I had to do). Signal came back, and I hit RTH, which I don't usually do, but I wanted to try it out (again, still VLOS and well clear of fog/clouds). Suddenly, it shot up to 400 feet from around 300. RTH height was about 150, I think (I haven't downloaded the logs yet, but I'm sure they'll show I screwed up somehow, and I'll do that soon).

At that height, there was enough mist/fog that I assume the sensors thought it was surrounded by obstructions and stopped it from going anywhere. It wouldn't respond to my commands in any direction when I tried to move it (I was getting an intermittent connection at this point), and RTH wasn't letting it come back either. I sort of freaked out, and tried my best to drive it home, but no luck. It would not move. I had video downlink, and I could see the ground, but it was pretty foggy. FINALLY I got a good connection back and was able to bring it down to 300' and start flying home, but got a critically low battery warning and it started landing. I pointed the camera down and found the clearest spot I could, put it down, and ran a few minutes to get it about 1/2 mile away. A little dirty, but undamaged.

So, lesson learned. As I said, I know to stay away from fog, but I will be far more cautious in the future. I was not expecting it to be totally unresponsive, but I think the fog made it think it was "locked in."

 

[RayOZ]

If you still had connection, cancel RTH and turn on Sports Mode. That should disable OA and you should have control of your drone.

 

[JDawg]

This may have been covered (I saw some posts anecdotally touching on it but nothing directly addressing it) so I wanted to share my experience.

I was recently out flying with my relatively new Air (about 10 hours flight time). I was about 3/4 mile from home, flying over farmland. Visibility wasn't great, but I could maintain VLOS. AWOS at the airport 10 miles away showed a ceiling at 1500' AGL. There were also patches of fog around, but I managed to stay well away from them. At some point, I lost the signal. Not a huge concern, as it had a clear route home, and even worst-case scenario, I could run and get it (to give away the ending, that's what I had to do). Signal came back, and I hit RTH, which I don't usually do, but I wanted to try it out (again, still VLOS and well clear of fog/clouds). Suddenly, it shot up to 400 feet from around 300. RTH height was about 150, I think (I haven't downloaded the logs yet, but I'm sure they'll show I screwed up somehow, and I'll do that soon).

At that height, there was enough mist/fog that I assume the sensors thought it was surrounded by obstructions and stopped it from going anywhere. It wouldn't respond to my commands in any direction when I tried to move it (I was getting an intermittent connection at this point), and RTH wasn't letting it come back either. I sort of freaked out, and tried my best to drive it home, but no luck. It would not move. I had video downlink, and I could see the ground, but it was pretty foggy. FINALLY I got a good connection back and was able to bring it down to 300' and start flying home, but got a critically low battery warning and it started landing. I pointed the camera down and found the clearest spot I could, put it down, and ran a few minutes to get it about 1/2 mile away. A little dirty, but undamaged.

So, lesson learned. As I said, I know to stay away from fog, but I will be far more cautious in the future. I was not expecting it to be totally unresponsive, but I think the fog made it think it was "locked in."

Please post your flight log. DJI Flight Log Viewer | Phantom Help
One thing I wonder about when people are getting intermittent connection and are hitting RTH are they actually cancelling it since when the bird loses connection it defaults to RTH.

 

[DanMan32]

That should be discernible by the RTH sound (or lack of it), and there's a red circle with white X on app screen to cancel RTH.

 

[Maviac]

Please post your flight log. DJI Flight Log Viewer | Phantom Help
One thing I wonder about when people are getting intermittent connection and are hitting RTH are they actually cancelling it since when the bird loses connection it defaults to RTH.

If I had to guess I’d say you’re right, at least in my case. Another lesson learned. I’ll post the log when I can, but I don’t have my iPad with the data with me so it will be a while.

(Or rather I should say, I “knew” that, but in the panicked moment it wasn’t in my mind as I was frantically trying to get it home).

 

[Astom22]

If I had to guess I’d say you’re right, at least in my case. Another lesson learned. I’ll post the log when I can, but I don’t have my iPad with the data with me so it will be a while.

(Or rather I should say, I “knew” that, but in the panicked moment it wasn’t in my mind as I was frantically trying to get it home).

Panic is tough with these expensive little toys. It's hard to stay calm when you see your hard earned money flying away/crashing/not behaving as it should. Then we go and make it worse without realizing it.

Not saying that's what you did, just my observation from personal experience and reading threads on here.

Luckily experience brings calmness, but it just takes a while to get there. I wish I was independently wealthy and didn't have to care.

 

[Maviac]

Panic is tough with these expensive little toys. It's hard to stay calm when you see your hard earned money flying away/crashing/not behaving as it should. Then we go and make it worse without realizing it.

Not saying that's what you did, just my observation from personal experience and reading threads on here.

Luckily experience brings calmness, but it just takes a while to get there. I wish I was independently wealthy and didn't have to care.

I hear you. There’s an interesting mental component there, I think. During my private pilot training, I spent a ton of time being thrown into simulated failures of various types (engine failures, spins, fires, etc.). I couldn’t get my pilot certificate until I proved to my instructor and the FAA examiner that I could safely deal with them. In the back of my mind, although I thought of myself as a very competent and well-trained pilot, I always wondered what I’d do if faced with an actual emergency, notwithstanding all the emergency training I’d had.

When I was faced with an actual emergency in a real plane (which happened only once in my flying career, so far), I felt fine. I didn’t panic. I felt a little nervous, but I was focused on solving the problem. I dealt with it and everything worked out fine. I was actually really surprised at how calm I felt, but after talking with other pilots who had similar situations they all seemed to have had similar experiences.

I think I felt more panicked when I lost contact with my drone that I did when I had an engine problem in an airplane, which is stupid from any logical standpoint, because obviously my life was not in danger with the drone issue, and even if I’d lost it (which wasn’t really an issue - I was over clear farm land, though there were a few narrow tree lines around, and worst-case I have DJI Refresh) I could probably replace my air for $600 or so, which, while not a small amount of money by any means, is less than 4 hours of what I pay to fly an airplane. (I’m also not wealthy, independently or otherwise, but I’ve been saving up for years to get back into flying airplanes and decided drones would be a good proxy).

I’d like to think the relative level of panic is a result of training (in which respect I have no drone training other than my own fairly cautious exploration, vs. my FAA required pilot training). But I suspect it’s more human impulse when there’s a life threatening issue.

But not entirely; training and experience are hugely invaluable in appropriate confidence in flying these things. If someone offered a course in Mavic flying I’d take it, even though they’re easy enough to fly that most anyone could fly them.

I’ve learned an enormous amount just reading these forums. Thanks to everyone.

 

[Maviac]

If you still had connection, cancel RTH and turn on Sports Mode. That should disable OA and you should have control of your drone.

Of all the great advice on this thread, this is probably the best. Or at least it would be if I ever ended up in this situation again, which don’t plan to.

 

[Maviac]

Of all the great advice on this thread, this is probably the best. Or at least it would be if I ever ended up in this situation again, which don’t plan to.

If you still had connection, cancel RTH and turn on Sports Mode. That should disable OA and you should have control of your drone.

If I’ve lost connection, and switch to Sport, will that (meaning the Sport Mode switch) be communicated to my Air as soon as it reestablishes communication? If so that would have solved my problem (because I was in and out of communication, but if I could have had it for even a few seconds I think I’d have been able to get it out of the fog, especially at sport speeds).

Also: I’ve seen comments about trees blocking signals due to water content. So I’ve made sure that while maintaining VLOS I don’t have tons of trees between me and my aircraft, or have maintained a high altitude. Question is: does high humidity affect range?

 

[msinger]

Signal came back, and I hit RTH, which I don't usually do, but I wanted to try it out (again, still VLOS and well clear of fog/clouds). Suddenly, it shot up to 400 feet from around 300. RTH height was about 150, I think (I haven't downloaded the logs yet, but I'm sure they'll show I screwed up somehow, and I'll do that soon).

The downward sensors were most likely detecting the fog as an obstacle. If Landing Protection is enabled, that'll cause the Mavic Air to automatically ascend in order to avoid the obstacle. This occurs even when the aircraft is above the RTH altitude or max altitude.

If you upload your TXT flight log here, you can confirm this by checking the "VPS Altitude" column. If it's showing anything other than 0 when the Mavic is not close to the ground or above ~26 feet (the max detection range of the downward sensors), that's a sign that something is beneath the aircraft.

If you know you're going to be flying through fog, you can work around this issue by disabling the "Landing Protection" setting in the following section of DJI GO:




This setting can also be disabled mid-flight if you suspect this might be an issue and forgot to disable it prior to taking off.

 

[Jblah]

thank you for the post! good to know. looks like sports mode might have helped in this case as a quick solution and disabling landing protection would have helped if you are not panicking

 

[msinger]

looks like sports mode might have helped in this case as a quick solution

Enabling Sport mode does not disable Landing Protection. Your only options would have been to disable Landing Protection or Vision Positioning (which also disables Landing Protection).

 

[Jblah]

Enabling Sport mode does not disable Landing Protection. Your only options would have been to disable Landing Protection or Vision Positioning (which also disables Landing Protection).

is that the only way? What about hitting this button:

 

[msinger]

is that the only way?

It's the only way if the downward sensors were being triggered. You need to review your flight log to check.

 

[DanMan32]

I was going to say that we've heard of RTH getting stuck reaching max altitude trying to get around obstacles, but pointing out VPS, then in this case it wouldn't consider itself anywhere near max altitude.

 

[Turn11]

thank you for the post! good to know. looks like sports mode might have helped in this case as a quick solution and disabling landing protection would have helped if you are not panicking

A thought. The PAUSE button on the RC

@Maviac was talking about the extensive training and preparation when he was taking lessons as a private pilot. IF only he had a PAUSE button oh the fixed wing AC.
There is a LOT of options and controls on any of the DJI line of drones. A beginner (like myself) can take it up in beginner mode and get a feel then spread my wings. Having read the manual many times there are still things I have don't have committed to instant proper response.

When things get out out of hand, the stop action PAUSE button can give you a moment to get your wits back together.