Flying over water?

[Jeremy Clark]

As PhiliusFoggg says above, be really careful of wave spray. I was flying over the sea & got hit by spray from breaking waves. My MA2 went haywire with loads of error messages. Thankfully, it RTH but all the camera & GPU info was totally ruined & it had to be sent away for repairs. Other than that, I've had no issues over water with the MA2S, although I too have found the Mini2 less stable the nearer it gets to water

 

[Drone-Retriever]

Flying over water with the sun overhead that is like flying over a mirror. The sensors get confused. Always be ready to ascend the drone manually. For insight on water events check out drone-retriever.com.

 

[tlswift58]

I have a question I have never flew over water and I know a bunch of you guys do, what I'm asking is what is my minimum height to fly safely without my ma2 taking a swim? TIA

Really depends on water you are flying over IMHO. For the ocean - I'd stay a good 10 - 20 feet above wave height. You never know when a rogue wave may come and you don't want to be caught unaware.

For rivers, creeks, and lakes - I'd stick to maybe 5-10 feet at lowest point. Weather conditions would greatly apply, as if there is any kind of wind (not created by water movement) - then go higher. Also water does create wind, so I'd drop to say 10 feet above the water and hover for a minute - keeping constant watch on the drone - not the video screen. If it feels pretty stable, then I'd stick to that height and not go lower.

I do a lot of over water - rivers / creeks / waterfalls and 10 feet is pretty low. Esp around falls - wind becomes a big issue.

Another caveat - GPS reception. Sometimes I get it fine and other times nope - fly in ATTI mode. GPS does provide good stabilization and so the drone does not move as much by itself and the forces around it - rushing water, wind, etc. ATTI Mode is a whole different ballgame. The drone IS affected by everything and can / will do things suddenly and unexpected. Ask me how I know? 10 feet is not a great cushion when flying in ATTI. If doing video - go higher and add a touch of zoom and you'll get same scenery with less chance of ditching the drone.

Last, but not least. Practice a lot - starting a bit higher - say 25 feet and working your way down. The more comfortable you are flying, the better you will react when something pops up - and it will. I have a drone buddy who is a "cowboy" and loves flying low and doing crazy things. He's very good, but at same time - he has dropped 4-5 drones doing so. He does have insurance, not DJI, and so he has replaced most of those he lost. Some he found, some not.

 

[hiflyer201]

What are updrafts/downdrafts, Trebek?

Up and downdrafts are rising and descending currents of air. They do come into play especially near the shore and over nearby land The air is cooler over and near water and therefore you have descending air currents. How much they effect the barometer and sensors in drones I don't know. I fly from an airport, KWJF, that has a small lake just off the left wing on final approach and pilots always encounter sinking air on about a half mile final. I just account for them without thinking I guess. I rarely fly my drone over water but when I do I always keep a reasonable altitude. I figure if I want a low level shot it would probably be better done with a boat or on foot.

 

[Meta4]

The sensors get confused. Always be ready to ascend the drone manually.

You see people saying this all the time.
But what they don't understand is that the VPS sensors only contribute to horizontal position holding.
It has no effect on your altitude holding.

 

[Capt KO]

i have noticed with mini 2 is that if I stand still over water 2 m. its slowly landing by itself. Maby water reflection messes sensors up or smth.

Had exactly the same with my mini. Under 10 ft it would slowly descend all the way to the water. Don’t care what others say, happened to mine too. Scary until expected.

 

[Meta4]

Had exactly the same with my mini. Under 10 ft it would slowly descend all the way to the water. Don’t care what others say, happened to mine too. Scary until expected.

The original Mini had trouble maintaining altitude over land or sea.

 

[MS Coast]

Something you won't encounter over water,
And something you would rarely find anywhere with sufficient strength to cause concern to a drone flyer.

The idea that wind over water could or would push the drone down just doesn't fly.

Interesting reading here:

Mountain wave turbulence

Mountain wave and associated turbulence
"In 1966, clear air turbulence associated with a mountain wave ripped apart a BOAC Boeing 707 while it flew near Mt. Fuji in Japan."

Turbulence/downdraft/rotor does exist downstream of objects with wind blowing over them and it becomes stronger as wind speed increases. The reference provides a good discussion of the effects near mountains and the dangers to aircraft.

Since the behavior of fluids (like air} scales very well you can expect the same effect with smaller obstacles like a line of trees, a row of beach houses, or a jetty. (A 10-foot model of a 747 in a wind tunnel can be used to predict the way the real thing flies. That's a standard part of much aircraft design. And tow tanks for ship design.)

Drones, whether over land or water, are subject to similar effects on a smaller scale. It's definitely something to be aware of when flying in stronger winds near obstacles, over land or water. I'm comfortable flying along the upwind side of the rock jetty near here in a fresh breeze, but I'm not going to get low on the downwind side.

Note: I'm not suggesting that the crash discussed here happened because of a downdraft or turbulence. And I'm not suggesting that it's a common occurrence with drones. But physics is physics. The effect is certainly real.

 

[SpitFire]

Flying over water VLOS is very important especially if flying close to the water. Watching the screen from a block away can be very deceiving.

 

[Meta4]

Drones, whether over land or water, are subject to similar effects on a smaller scale. It's definitely something to be aware of when flying in stronger winds near obstacles, over land or water. I'm comfortable flying along the upwind side of the rock jetty near here in a fresh breeze, but I'm not going to get low on the downwind side.

The idea that you'll encounter downdrafts strong enough to overpower your drone's vertical position holding ability, while flying over water is a fantasy.
It just doesn't happen.

 

[Wreckhunter]

I have a question I have never flew over water and I know a bunch of you guys do, what I'm asking is what is my minimum height to fly safely without my ma2 taking a swim? TIA

Hi
I have the mavic air 2 and never go lower than 40feet above the water ,for shipwreck photos.
I just do not want to push it,and I have the sensors turned off,but do not know if it matters or not.

 

[AZDave]

Flying over water is just like flying over solid ground.
Except that there are no trees, buildings etc to run into and there's less interference.
Use the same minimum height you would for flying over land.

That simply isn't true, and it isn't going to be true no matter how many times you make posts here saying it is. Over land, the bottom sensing collision avoidance infrared sensors are reasonably reliable at doing their job ... preventing (or at least warning) you or your drone from making a mistake. That "mistake" could be operator error, a change in barometric pressure that the drone uses to tell how high it is, a downward wind shift, or some other influence. Over water, on the other hand, the infrared sensors are much less reliable since infrared light can penetrate water. It's simple physics.

Another obvious difference is that the risk of completely losing your drone is greater over water, either due to lack of access or corrosion damage.

I don't know how many times it's going to take for people to lose their drones over water before they learn to apply more margin than over land.

 

[AZDave]

The idea that you'll encounter downdrafts strong enough to overpower your drone's vertical position holding ability, while flying over water is a fantasy.
It just doesn't happen.

That's probably true, although I wouldn't totally rule it out. What IS more likely is that the barometric pressure could be significantly different over water than over the land at the takeoff point ... at least different enough to cause problems for the folks who think flying three feet above the water is a good idea. You can fly a few feet above the land and count on the infrared sensors to override the barometric pressure sensors if you dip too low ... but over water that isn't the case since infrared light can penetrate water.

 

[JPC]

We have done a lot of tests over the water and wind is much more likely to effect the drone as it can push it down. Waves on the water can push up the drone because of the sensors , but we have yet to have the sensors force land the drone on the water without the help of the wind in over 100 flights on the water.

Phantomrain.org
Gear to fly in the Rain and Land on the Water.

I have a Mavic Air 1 - does the PhantomRain life jacket for the Mavic Air2 fit it? and do I also need to have a waterproof jacket for the battery? I am planning on a sailing trip and wish to fly my Mavic Air around the yacht on the open seas - hence the questions, so grateful for any advice and recommendations.

 

[oldfartflyer]

I have a Mavic Air 1 - does the PhantomRain life jacket for the Mavic Air2 fit it? and do I also need to have a waterproof jacket for the battery? I am planning on a sailing trip and wish to fly my Mavic Air around the yacht on the open seas - hence the questions, so grateful for any advice and recommendations.

Amazon sells floats for the Mavic-air-2. Work great on still water,just sayin

 

[LeadSledGirl]

What are updrafts/downdrafts, Trebek?

I’ll take Low Level Wind Sheer for $800.

 

[PaJi]

I've been flying a lot over a lake in N.H. w/ my M2. I've noticed that if I'm at 10' or lower sometimes the drone drifts downward so I watch it very carefully. I read somewhere that the downward sensors don't always read water properly. Not sure if that is the problem but mine likes to drift down at times. I have flownvery cautiously over water 2' but only with someone else I trust visually monitoring the drone's altitude. For distance I keep it about 40-50 feet since I'll have limited perception of actual altitude over water as it gets further away. Perhaps over cautious but it beats losing the drone. Wind can also surprise me but others have commented on that. Given all this, I thoroughly enjoy flying over water.

 

[Interficiam Stercore]

It's hard to be watching your height and create a video of a subject on or in the water. I won't go lower than 20 feet when recording a subject because i'm looking at the video I'm creating, I can't look at the drone and the altitude readout at the same time. If i'm lower than 20ft, it would just take second for me to inadvertently lower the drone when manually circling a subject in or on the water. It gets hairy flying in circles and paying attention to the composition of the video.

 

[MA2 317]

It's hard to be watching your height and create a video of a subject on or in the water. I won't go lower than 20 feet when recording a subject because i'm looking at the video I'm creating, I can't look at the drone and the altitude readout at the same time. If i'm lower than 20ft, it would just take second for me to inadvertently lower the drone when manually circling a subject in or on the water. It gets hairy flying in circles and paying attention to the composition of the video.

I've been recording PWC (Jet Ski) practice on a closed course and I agree about flying below twenty feet.

My wife usually accompanies me as a visual observer.

She's quite helpful to have a set of eyes on the aircraft when I'm concentrating on the content if I'm below twenty feet.

.

 

[Meta4]

That simply isn't true, and it isn't going to be true no matter how many times you make posts here saying it is.

And I'll say it again.
Flying over water is just like flying over solid ground.

If you want to fly so close to any obstacle, whether that's water, the ground or trees, you are in a risky environment and need to be careful to avoid flying into the obstacle.
All that stuff about sensors, air pressure etc is misinformation and myth.
Find a case where the data shows any of that caused an incident if you want to convince me.