[pmilla1606]

I think 230mph is unrealistic for such tests. A quick google search shows something between 70mph - 100mph on approach [1]. I doubt drones are found at altitudes of aircraft at cruising speed.

I'm not saying that this isn't a concern but can somebody with actual aviation knowledge (I have none) chime in and explain the 230mph figure?

1: http://www.mooneyland.com/how-to-land-a-mooney-properly/

[tlb]

Landing speed for a loaded 737 can be up to 203 mph [0]. Among general aviation, a Gulfstream 450 landing speed can be up to 186 mph at full weight and high altitude. The drone itself can have some speed opposite to the airplane. 230 mph is only a little conservative.

[0] http://www.b737.org.uk/vspeeds.htm Note that numbers are in knots.

[1] http://www.code7700.com/g450_vref.htm

[pmilla1606]

But surely a 737 wing is completely different to the one tested here?

I'd be very interested to see a 737 wing being tested like this.

[falcolas]

Completely different? No. Still mostly aluminum sheets riveted to spars with a big ol' gas tank in them. Biggest difference is the control cables would be mostly replaced with hydrolic lines.

[bronco21016]

Your referenced speeds for the 737 are for an overweight landing at the lowest allowable flap setting. 186 mph for the G450 would also occur at a weight above max landing weight. An incredibly low likelihood.

[bufferoverflow]

But we should consider the worst case scenario, not an average one. Thus 230 mph is conservative. They didn't even consider fast gliders, which alone can reach 460 mph.

[bronco21016]

Do you have a reference for fast gliders? I’ve never heard of anything like that.

I don’t think the FAA plans everything for the worst possible scenario. The odds of a classic 737 landing at max take off weight and thus high speed are infinitesimally small. I don’t have a landing distance chart but at the max over weight landing it likely can’t even land on 99.99% of runways in the US in that configuration.

If the FAA planned and approved everything at worst case scenario then we wouldn’t fly anywhere.

[sokoloff]

14 CFR 91.117 restricts aircraft to 250 knots indicated under 10K feet.

[bufferoverflow]

Yet you can go on YouTube and see people fly them.

[protomyth]

The 230mph is combined speed and they don't mention approach as the time of impact. Single engine prop planes can do between 140mph to 200+mph for some of the fast ones. Some of the business jets have higher landing speeds also. You would be surprised how low a lot of these planes fly over rural areas, they are well within range of some of these camera drones doing crop pictures.

[oldgradstudent]

Sadly, there are quite a lot of imbeciles flying drones well beyond the legal limits.

https://www.youtube.com/watch?v=I5izg2cueP4

https://www.youtube.com/watch?v=GPpEnojFTwU

[ratsbane]

It's very unlikely that a drone would hit an aircraft wing at combined speed that high - but certainly possible. I'd be more concerned about one going through a windshield at a slower speed and damaging the pilot.

In US airspace, there's a speed limit of 250 knots (around 290mph) below 10,000 feet. Most light aircraft cruise significantly slower (~140 mph for a Cessna 172) and closer to the ground, whether on approach, takeoff, or other, most aircraft are likely to be going slower than that - so this test is at the high end of that range, even if you add the maximum speed of a DJI Phantom (~40mph) and assume it's flying directly at the aircraft.

[gjhan]

Your point that speeds are restricted to be lower at lower altitudes is really salient to the discussion because it's an intentional procedural mitigation for collision hazards in the more densely-populated and less-controlled airspace down low. Drones were but a glimmer in anyone's eye at the time the regulation was emplaced, but the same theories are still relevant.

Bear in mind though that the under-10,000 ft limit is knots of "indicated airspeed", which is a constant-dynamic-pressure pseudospeed uncorrected for density. 250 KIAS at 10,000 ft is about 290 knots/330 mph relative to the airmass, and sometimes up to 10 kt faster on a hot day.

[bronco21016]

I agree. 230 mph seems high. Most commercial airliners and business jets make their approach at no greater than 150 knots which rounding up is 175 mph. I think the latest DJI drones do about 40 mph.

A drone striking a Mooney at 230 mph seems pretty unlikely. One has to ask what the GA pilot is doing if he’s flying 200 mph at 400 ft or less. It’s not necessarily an unsafe operation but it would definitely be an abnormal operation.

Edit: As pointed out elsewhere the latest DJI Phantom does 40 mph. Updated post to reflect that.

[djohnston]

what about takeoff?