If you’re planning a trip to the mountains, it could be a perfect opportunity to get in some time flying your drone. But perhaps you’re wondering about how well your drone will perform in a higher altitude setting, and for that matter, whether it’s even allowed.
It is certainly possible to fly a drone in the mountains, although you might have some degree of difficulty if you are in very high mountains, due to lower air density at higher altitudes. You may also see some shorter flight times due to a greater drain on your batteries from altitude as well as cold.
That’s not to say that you shouldn’t give it a go. Mountains offer some spectacular vistas from the air, and it’s a great opportunity to practice honing your flight control skills as well as capturing some great aerial photos and videos. With a few tips to keep in mind about how to safely and responsibly fly in the mountains, it could become your new favorite place to fly.
Drone Performance at Higher Altitudes
Not all mountains are created equal. Mountains on the east coast of the US, for example, rarely go higher than about 6,000 feet. Even on the very tops of mountains of this height, typical consumer drones are not going to face much of an issue in terms of ability to fly. At a height of 6,000 feet, you may begin to see about a 10% reduction in battery power, and this would hold true for each further 6,000 feet that you increase in altitude. This loss of battery power has to do with the decreasing air pressure, making it harder for the propellers to generate lift.
Most drones are not going to lose their ability to generate enough lift to get airborne until they reach about 13,000 feet. (Although specialized high altitude propeller blades can enable some drones to fly even at this height). If you are in the Rocky Mountains, there are only a handful of mountain peaks that exceed this height, leaving you plenty of places, even on mountaintops, where you will be able to successfully fly your drone.
One thing to keep in mind is that if you are flying at higher elevations, air temperatures tend to be colder the higher you go. Most drone batteries have notoriously poor performance in cold temperatures, and this may also lead to decreased flight time, in addition to the drain from the lower air pressure lift factor. You can try to address this somewhat by keeping spare batteries warm by keeping them in your pockets. But the bottom line here is that you can’t expect to get the advertised flight times if you’re in a cold location, at a higher elevation.
Another important factor to keep in mind when flying in the mountains is the effect that wind currents and terrain will have on your drone’s flight. Equally challenging to the altitude question is the wind question. Keep in mind that winds tend to rise on the sunny side of a mountain, and tend to fall on the shaded side. Also be aware of wind turbulence near cliff faces, and through valleys. This knowledge of wind patterns can help you be prepared for updrafts or downdrafts and avoid potentially problematic situations.
Mountains are also known for sudden and dramatic shifts in weather, so be sure to be paying attention to weather reports before heading out, and once you’re out there, watch the sky and clouds for signs of oncoming storms. Sudden storms could mean unpredictable wind patterns which might be difficult to fly in, and might even cause your drone to crash. They could also mean lightning storms, which are not safe for you or your drone. Getting caught in the rain is not going to do any favors for your drone either.
If you’re not an experienced and confident pilot, you may not want to let your drone venture too far over inaccessible ground. If it should happen to come down, and you’re not able to get it up again, the rough terrain may make it extremely difficult or unsafe for you to reach it by foot. Until you’re absolutely confident in your ability to control your drone in mountain conditions, best to keep it relatively close.
Responsible Flight in the Mountains
So far we’ve been talking about the ability of drones to perform in mountain conditions. But let’s talk for just a bit about the permissibility of flying a drone in the mountains. (Remember those two different uses of “can” from English class?)
Drones and Parks
A trip to the mountains sounds like an ideal setting to fly your drone, right? No people around, no buildings to worry about. But, keep in mind that drones are not allowed in most state parks or in any national parks. This ban on drone flight also applies to designated wilderness areas. If you’re not sure about whether the area you are headed to falls within park or wilderness area boundaries, be sure to check a map beforehand.
If you break the rules and get caught, you could be facing a hefty fine of up to $5,000, and probably depending on how obnoxious you are about the whole thing, you might land yourself in jail for up to 6 months. There are plenty of mountainous areas that do not fall within state or national park land, so do your homework before you go, and find out where you are allowed to fly, and where you’re not.
400 Ft. Altitude Restriction
Even the most uninitiated drone pilot among us has heard something about the 400 ft. altitude restriction. So how does this play in if we’re planning to fly in the mountains where the top of a mountain may well be more than 400 feet higher than its base?
Most drones come with a programmed altitude limit to prevent the drone from flying above the 400 foot Above Ground Level (AGL) restriction. These built-in altimeters are designed to set the “zero” level as the take-off point (where the drone takes off from, not necessarily where you with the controller are standing).
This means that if you take off at the bottom of a cliff face, you may not be able to reach the top of it without hitting the pre-set limit. Or, if you take off from the top of the cliff (zero), and fly out over the edge of it, you will technically be over the 400ft AGL limit, not to mention that you will have a negative altimeter reading. This will not be a functional problem for your drone’s operation, unless for some reason you land your drone at the bottom, and take off again – you may not be able to fly your drone back up to where you are.
Keep in mind that the rationale behind the 400 ft altitude restriction in the first place is not to interfere with manned air traffic. When you are flying a drone on or near mountain peaks, be aware that small aircraft might be fudging their 500 ft altitude minimum to get over a crest. If you are fudging your maximum height at the same time, it could lead to a tragic collision.
So for that weekend trip to the mountains that you’ve planned, definitely plan to take your drone along with you. Do just a bit of homework to find out where the best places to fly will be, outside of park land. Check the weather report, put your extra batteries in your pocket, and get on out there!