On guard!
Propeller guards and why experienced operators should consider them.
Do me a favour. Pop onto any social media drone group and ask whether prop guards are worth having? The response you get will tend to vary between “why would you even bother?” through “you should learn to fly”, to “definitely not”. More enlightened comments may refer to indoor jobs, lack of satellite lock and mitigation around cathedral windows.
Given this very negative view of propeller guards, why are we bothering with a blog on them in a group aimed at professionals? Would it surprise you to hear that I believe the CAA has probably increased the demand for these things two or threefold since late 2022?
Well, back then, the CAA introduced a stricter definition of Visual Line of Sight and published in within their AMC. The regulator then forces operators in the Specific Category to refer to the AMC within their operations manual. CAP 2606 (not yet released at the date of this blog) contains a detailed definition of VLOS flying and makes it very clear that “dot in the sky” operations are not acceptable. The December 2023 version of the PDRA01 template document states:
Options
Given this need to retain the ability to “determine the aircraft’s orientation at all times”, the general approach is to either keep the UA closer or add reflective stickers/strobes. But what else can you do?
You could buy a larger drone of course. Not cheap though and actually increases the risk of the operation in the event of an unscheduled plummet from the sky. If only somebody had an accessory that could make the drone look much larger in the sky, especially in daytime, and even provide it with a little bit of “shape”.
Step forward prop guards.
I have used them on an Inspire 2 to fly it more safely at 1000ft against an OSC, leaving the platform really clear against the sky and incredibly easy for my observer to judge in terms of position and orientation.
Although they aren’t available from DJI for the Mavic 3 platform in the UK (at least at the moment…a hangover from our involvement in EASA regulations and a perceived need to limit take-off weight), I managed to get a pair from B&H Photo in the US. Fit them to the Mavic 3 and the diagonal measurement increases from around 390mm to almost 700mm. Given that an Inspire 2 (without prop guards) has a diagonal measurement of 605mm, all of a sudden the Mavic 3 gains a lot of presence in the sky.
This is what prop guards bring. A much larger profile in the sky enable you to see the drone from further away and at certain heights it really assists in orientation, though the latter can depend on the guard design.
You need to allow mitigation for additional wind loading so they are not always the answer, and sometimes you may want to point the camera somewhere that the guards will ruin the shot. But at least you have options. And the more options you have, the more you can achieve within the tightest interpretation of the regulations.