If you're a pilot, you probably love to share your passion for flight with others. The best way is of course to take up a passenger. I absolutely love taking up passengers, but in a little two-seater Cessna, it's one at a time. More importantly, my pockets aren't that deep!

So I opt to share my flights with a broader audience using technology. Small action cameras have absolutely revolutionized the way people share their extreme (and not so extreme) passions. Flying is no different, and I am very proud that I have been able to create new student pilots through the photos and videos I've been able to share through these cameras.

That said, I'm always looking for new perspectives, and one of my favorites is the wing mount. This might make some pilots nervous, but my intent with this article is to demonstrate how it can be done both safely and effectively.

I also have a full write-up at:

http://theflyingshutter.bryanrolfe.com/

Step 1: The Legalities

Is temporarily affixing a camera to the outside of your aircraft legal? Well, technically, yes. Unless the mounted camera constitutes a change in the design (eg. you have to drill a hole, requires tools to install, any change to the structure), then you probably don't need a supplemental type certificate (STC).

According to FAR 21.111:

Any person who alters a product by introducing a major change in type design, not great enough to require a new application for a type certificate under § 21.19, shall apply to the Administrator for a supplemental type certificate...

That said, this is a gray area, and mounting a camera to any part of an air frame necessarily alters its aerodynamic characteristics. Just because it's legal, doesn't mean it's safe. Additionally, should the camera detach in-flight, you may be subject to FAR 91.13:

Aircraft operations for the purpose of air navigation. No person may operate an aircraft in a careless or reckless manner so as to endanger the life or property of another.

This isn't meant to scare pilots away from externally mounted cameras, but rather ensure that they understand the possible legal ramifications, as well as the importance of sharing their aviation experiences in a way that is both safe and in compliance with the law.

Step 2: Mounting Options

There are three main ways to mount a camera to the outside of an aircraft:

Use an industrial grade suction cup or adhesive mount
Use a tailor-made strut-style mount
Use a permanent mounting point

I exclusively use the first of these methods as it's the most flexible and adaptable. Option 2 is also one I support, as it provides a very strong place to mount multiple cameras, but you won't be able to get the same shots a camera mounted out on the wing would provide. If you're interested in the strut-style mounts, check out www.wingitmounts.com.

Option 3 is only an option if you own the aircraft, and are able and willing to do the proper analysis and create the legal documentation for the modifications made to the aircraft. I rent the plans I fly, so this one will not be discussed int his article.

That leaves the suction-cup style mounts.

Step 3: Suctions Cup Mounts, and Why They're So Strong

For small general aviation aircraft, suction cup style mounts, when properly used, provide a great option for externally mounting small action cameras.

The mount I use is the Official GoPro Suction Cup Mount, which isn't the cheapest such mount at $39, but this is one of those times I was willing to spend the extra money in hopes for a higher quality product. In my experience, the mount has performed flawlessly, on over a dozen short flights (~ 1 hour each in good weather).

Suction cups may sound like a dangerous way to affix anything to an aircraft, but there are some simple physics at work that make properly designed and used suction cups very strong.

When we push down on a suction cup, we remove all the air that was once present within the sealed region and create a vacuum when we expand that region. The expansion can either be a mechanical lever that locks down, like in the GoPro mount, or it can be just the material properties of the cup membrane and the weight of whatever it's holding.

There now exists an imbalance of pressure on each side of the suction cup membrane. Inside we have very low pressure, and outside we have 1 atmosphere, or 14.7 PSI.

Thus, the astosphere is pushing the suction cup onto the surface with 14.7 pounds per square-inch. The GoPro suction cup mount has a base radius of 1.7 in., so that makes about 9 square inches of suction cup. If you do the math, that's 9 in^2 X 14.7 pounds per square-inch = 132 pounds of force holding the mount onto the plane.

However, this assumes a perfect world, and this calculation depends on several assumptions:

A true vacuum is formed inside the membrane. In reality, the pressure differential is probably not 14.7 PSI.
We have a good seal on the cup, and absolutely no leakage.

We can't do much about the first item, and I imagine the holding force is probably closer to 60lbs. Regardless, the holding force only holds for forces perpendicular to the suction cup, and there may also be weaker components than the pressure holding the mount to the plane. I absolutely would not put anything heavier than a small action camera on this mount.

The second item we have control over, and in order to create a good seal, follow the following guidelines:

Follow the manufacturer's instructions to ensure proper creation of the vacuum, and that the device is locked.
Clean both the suction cup and mounting surface with a wet cloth
Only apply to dry surfaces
Understand that cold and warm weather may compromise the materials used in the suction cup membrane, and therefore the seal
Understand that excessive shaking, turbulence, or tangential forces may also act to break the seal

If done properly, these mounts are incredibly strong, and can not easily be detached. GoPro claims they've tested them successfully above 150mph. I've only taken mine to 100mph.

Step 4: Suggested Mounts and Cameras

I won't go into too much detail here, as it's not my intent to sell any one camera or brand, but these are a few mounts and cameras that I think lend themselves well to external mounting.

Mounts

The Official GoPro Suction Cup Mount ($39)
The Fat Gecko Suction Cup Mount ($29)
WingItMount's strut mounts (varies)

Cameras

Each of these options has it's pros and cons, and you can read more about those at theflyingshutter.bryanrolfe.com, but I'll provide a quick summary here.

For the mounts, the GoPro is the one I know, and I trust it with my Hero 4. The Fat Gecko mount appears to be built to similar quality, but has a 1/4" threaded attachment, making it good for more traditional cameras.

For the cameras, it's a compromise between size, weight, quality, and price. You want high quality video and photos, but you don't want anything more than 100-200g for safety reasons. However, you may also not want something expensive, in the unlikely event the camera were to detach. I think the GoPro Session is a good compromise, but if you're very nervous, maybe look into the EK7000.

Step 5: Being Safe and Getting Good Results

Be wary of tethers

Be aware of the risks associated with hard-line tethers.

I never use a tether, and I'm not a fan of tethering anything to an aircraft I'm flying (unless I were a banner or tow pilot). The motivation for using a tether is two-fold. One, it saves your camera in the event it were to detach, sparing you a financial loss. Two, it prevents injury to persons on the ground. I think the latter of these is noble, but not worth the potential risks, unless you're flying over populated areas.

The issue with a tether is that, once a camera detaches from its proper mounting position, it is now a liability, and it's a liability dangling from your airplane. It could whip back and forth in the air stream, impact flight surfaces, or get tangled in something important. There are probably safe ways to tether, but it's a tough thing to experiment with, so I avoid it altogether.

Avoid populated areas

As much as I can help it, I do not fly over populated areas while there is a camera attached to my wing. If the camera and mount were to detach, they could do serious damage to persons or property on the ground, and I'm not willing to put other people's lives at risk to share my aviation experiences. A strategy I suggest, if you're departing an airport in a metro or otherwise populated area, is to have an intermediate, rural destination, where you can get out, and configure your camera and mount.

I'm lucky in this regard, as most of my flights are along the Oregon coast, which has many small airports, and lots and lots of water for my camera to safely dunk into.

Understand your camera

Unlike a DSLR, action cameras are designed to be easy to use, and to have very reliable automatic shooting modes. As a result, we relinquish a lot of control over how our cameras choose to expose shots.

Cameras generally have 3 ways to adapt to low-light: increase exposure duration, decrease focal ratio, and increase sensor sensitivity. Focal ratio is a property of the optics, and can't be changed on most action cameras. That leaves exposure duration and sensor sensitivity .

Generally there's a happy balance between these two controls that results in a good outcome. However, they each have a drawback. Increasing sensor sensitivity increases the noise of your image. Increasing exposure length means that the sensor is exposed for a longer period of time, and any movement will result in blurring. In the shakey, windy environment out on a wing, you want a short exposure length, not a long one.

There's no real way to control this on most action cameras, but if you shoot in video mode, then the camera is forced to shoot a defined framerate. So if you're shooting at 60fps, then the exposure length can necessarily be no shorter than 1/60th of a second, meaning it will boost sensor sensitivity instead.

Maintain a low aerodynamic profile

The suction cup mount allows you to configure the camera in a variety of ways, but it's probably best to keep it as low to the airfoil surface as possible. Putting a big hunk of plastic onto a wing is undoubtedly going to change the airflow characteristics in that region. This changes stall characteristics, performance, and adds an asymmetry to the aircraft. Keeping the mount in a low-profile configuration may help minimize this effect.

A low profile also reduces the lever arm distance, and decreases the amount of rotational force acting on the panel supporting the suction cup. As a bonus, it also means you'll probably have more stable and less shakey footage.

Be smart about it

Your goal should be to share the joys of aviation, but not at the risk of others or yourself. Cameras, whether in the cockpit or outside, can be a distraction. I like the "set it and forget it" kind of attitude. Once mounted and recording, you have no reason to be thinking about it. Your job, as a pilot, is to fly the airplane.

This is a good opportunity for resource management. If you have a passenger, have them be responsible for checking on any cameras, or making sure things are working properly. This will keep you focused on looking for other traffic, and keeping your plane coordinated.