Most people can't judge the altitude of an aircraft. Military aircraft, including choppers, are very large, so people tend to think they are closer and lower than they actually are. The chance of a mid-air collision between a drone and a manned aircraft is extremely low. So low in fact that it has never happened. There's a lot of alarmist hype claiming close calls that probably were not at all close.
near miss with military helicopter
- Thread starter SteveEsqueda
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When I talk to local hospital hilo-pad operators, they say their medic helicoptors fly well above 500' and then descend vertically when directly above the landing pad. They say if drones fly outside of the hospital boundary line, there would be no problem. Then there is the special case ... military aircraft. Flying over the tree-tops as in Vietnam movies is not uncommon. I interpret the VLOS rule as having a clear VLOS for any manned aircraft that could hit your drone. In this case, there was not sufficient VLOS capability above the cliffs. Thanks for sharing your experience so that we can all learn from it.
It wont hit the helicopter.
I wont lecture people with physics but for simplicity lets just say the downward force produced by any helicopter will scatter your drone long before any impact.
I wont lecture people with physics but for simplicity lets just say the downward force produced by any helicopter will scatter your drone long before any impact.
That's a nice hypothesis, but rather easily disproved by the numerous documented records of birds colliding with helicopters. Physics is not that simple.
If you want to think of it as a physics problem then consider the following:
Take an arbitrary helicopter - I'm choosing a Sikorsky UH-60, which has a maximum takeoff weight of 10,000 kg and a rotor diameter of 16.4 m, sweeping an area of 211 m².
To support its weight the downthrust has to be 100,000 N, and so the downward pressure below the rotors needs to be of the order of 500 N/m².
The cross-sectional area of a Phantom is around 0.25 m², and so the downward force on the Phantom would be, at most, 125 N.
Acting on a mass of 2 kg, that will yield a downward acceleration of 62.5 m/s².
The UH-60 flies at 150 knots (78 m/s), and so the time taken for even a stationary Phantom to pass the 16.4 m under the rotors, front to back, would be 0.2 s.
Applying the standard equations of motion, vertically, to the Phantom, it will be deflected downwards by 1.4 m in that time, not even nearly the height of the aircraft.
But, since the fuselage is positioned such that only around one half the length of a rotor blade extends ahead of it, the time that an incoming Phantom would be exposed to the downforce before striking the aircraft would be roughly one quarter of the estimate above - i.e. 0.05 s. In that time the deflection will be around 7 cm. Barely noticeable - it's still hitting the windshield.
Every time I fly at my shop, I get the "You are in a helepad area, fly with caution". As I understand it, if you are flying and another craft, like a chopper, comes into view, you should make sure that they have right of way and that you are flying in accordance to all rules. My shop is within an area of 4 hospitals, so I get a lot of traffic overhead. Follow the rules, and be careful, you have "just" as much right to fly as anyone else does.
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Here are the actual rules on minimum safe altitudes.
Note particularly C & D ... there is no mention of any distance offshore
§ 91.119 Minimum safe altitudes: General.
Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:
(a) Anywhere. An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface.
(b) Over congested areas. Over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft.
(c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.
(d) Helicopters, powered parachutes, and weight-shift-control aircraft. If the operation is conducted without hazard to persons or property on the surface—
(1) A helicopter may be operated at less than the minimums prescribed in paragraph (b) or (c) of this section, provided each person operating the helicopter complies with any routes or altitudes specifically prescribed for helicopters by the FAA
Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:
(a) Anywhere. An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface.
(b) Over congested areas. Over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft.
(c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.
(d) Helicopters, powered parachutes, and weight-shift-control aircraft. If the operation is conducted without hazard to persons or property on the surface—
(1) A helicopter may be operated at less than the minimums prescribed in paragraph (b) or (c) of this section, provided each person operating the helicopter complies with any routes or altitudes specifically prescribed for helicopters by the FAA
Try slipping the drone, just like a airplane. On a airplane you cross control the ailerons and the rudder on a drone full down and full left or right and you can "slip" the drone down. This works well on small aircraft can get touchy on large jet aircraft.
Would be interested to learn if this is even possible on the more recent DJI AC, consensus is that the flight controller will, to the extent possible, limit maximum decent to a prescribed value regardless of user commanded input.
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Though I would not wish to try, if a military helicopter can either be damaged or brought down after suffering an impact with a mainly plastic drone. The military have some serious problems not only in flying in an area that has large flocks of seabirds but if a potential enemy knew this then the air space above Siria or Iraq would have clouds of drones......As for all the money that goes into "militarizing" equipment I am sure that the possibility of FOD has been thoroughly tested!
I feel the outcome would have been helicopter 1 drone 0
Sorry WTB, this works with anything that produces lift,fixed wing,helo,no balloons. P.S. Remember to release everything a little sooner due to higher rate of descent .
WTB,let me retract that statement with the advancement of computers today we may defy physics soon.
That's not going to work, (1) because it's not really a rudder control, it's an instruction to the FC to rotate the drone, (2) it's not an aileron control, it's an instruction to the FC to fly sideways, and (3) because whatever combination of stick that you supply (excluding the actual CSC), the FC will not allow descent rates above the limit.
The issue, with a military helicopter, is likely not that there is any chance of bringing it down but rather the trouble that you will get into if you collide with one.
You're awesome! My 93 year old Italian Mother would say, "you could have been something!"....
It's already happened- your suggested manoeuvre doesn't work with the P3. The same as fitting fancy props won't increase max speed, the FC simply compensates to keep maximum pitch within prescribed limits.
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I agree, I live in an area where we have a high number of Army and Coastguard helicopters, my immideate response on hearing a helicopter is to drop down as low and as fast as possible,,,,
You stated that it was an area with a heavy population of seabirds, at that speed and low altitude the helicopter pilot was simply not using common sense, ingesting a large seabird would probably ruin his day, though this would not help you had you hit the aircraft, the FAA would have ruled against you had they collided with a drone
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There is a TFR all the way into Massapequa and Seaford. I won't fly anywhere near there or during the day as I saw the Thunderbirds buzzing Medford on Friday. A few years back a Blue Angel buzzed by when I was flying. You want to talk about butt puckering. Wow
Okay, you're going to think this a bit ridiculous, but since the minute I saw the Mavic I am just waiting for someone to James Bond-throw that little bastard out the window of a car and activate it before it hits the ground.
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Helo operators rarely do vertical descents to landing from significant height. First off, if the engine quits, he'll be in poor posture to autorotate, then there's bad viz, bad aerodynamics , takes long, not safe.
Hospital VFR approach guide from the FAA has the helicopter at 500' at a distance of 4000' from the FATO edge (8:1 approach slope).
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