Surge
Well-Known Member
- Joined
- Apr 22, 2018
- Messages
- 87
- Reactions
- 34
- Age
- 50
It certainly is not. I'm a commercial pilot. See my point just above this.
Watch out for US Coast Guard helicopters flying below 500 feet without warning
- Thread starter Dangerly
- Start date
tleedom
Well-Known Member
You cant tell that from the posts being made.
As I posted above CFR 91.119
(d) Helicopters – Helicopters may be operated at less than the minimums prescribed In paragraph (b) or (c) of this section.
This means helicopters have no fixed altitude restrictions:
" If the operation is conducted without hazard to persons or property on the surface."
This is the pilots responsibility/decision not a regulatory limit.
Your previous post points out that there is no minimum altitude requirement for manned airplanes in sparsely populated areas. They can legally fly below 400' AGL in such areas.
I'm aware of no requirement for a manned aircraft pilot to avoid a drone. Can you cite a reference?
There is a requirement for drone pilots to give way to manned aircraft and others.
§ 107.37 Operation near aircraft; right-of-way rules.
(a) Each small unmanned aircraft must yield the right of way to all aircraft, airborne vehicles, and launch and reentry vehicles. Yielding the right of way means that the small unmanned aircraft must give way to the aircraft or vehicle and may not pass over, under, or ahead of it unless well clear.
(b) No person may operate a small unmanned aircraft so close to another aircraft as to create a collision hazard.
tleedom
Well-Known Member
So your are saying that is not the UAS pilots responsibility to avoid manned aircraft?
That raises an interesting question about the altitude figures being reported. FlightRadar24 reports "calibrated altitude' and "GPS altitude" for aircraft with Mode S ADS-B, both as reported by the aircraft's ADS-B transponder.
Both altitudes are referenced to MSL. So, they don't reflect that altitude of the aircraft above ground level. To estimate the actual AGL altitude of an aircraft, you need to factor in the local terrain elevation relative to MSL.
Another question that complicates those reported altitudes is what is the pressure reference the aircraft's altimeter is using? The takeoff field elevation? Standard barometric pressure - 29.92? Has anyone researched that?
Bottom line: don't read the flight tracker app altitude as AGL altitude.
Pretty cool to watch them fly through that canyon. They have a similar canyon in the UK.
Helicopters are usually easy to hear coming from a long distance away so there's usually a 10-20 second warning to get out of the way. But my recent near-collision experience was with two military fighter jets flying at around 400' AGL or lower in rural North Carolina as I was photographing a large vacant land property.
I heard a low rumble in the distance and then they were right over the treetops going probably 500-600 mph - they were there and gone in about the time it took for me to inhale. It was hard to tell from the ground how close they actually came to the drone but I estimated that there had not been a great deal of separation. Heart in my throat, I landed immediately and took several deep breaths thinking about what could've happened!
There are always lots of military aircraft flying around the several bases in NC - Blackhawks and Ospreys are what I usually keep an ear out for (as well as the Coast Guard near the coast). So this was a reminder to me to be more vigilant when flying and to execute my emergency plan to immediately descend whenever I hear loud aircraft sounds in the vicinity - this experience, though, added a new sound to be on the alert for.
I heard a low rumble in the distance and then they were right over the treetops going probably 500-600 mph - they were there and gone in about the time it took for me to inhale. It was hard to tell from the ground how close they actually came to the drone but I estimated that there had not been a great deal of separation. Heart in my throat, I landed immediately and took several deep breaths thinking about what could've happened!
There are always lots of military aircraft flying around the several bases in NC - Blackhawks and Ospreys are what I usually keep an ear out for (as well as the Coast Guard near the coast). So this was a reminder to me to be more vigilant when flying and to execute my emergency plan to immediately descend whenever I hear loud aircraft sounds in the vicinity - this experience, though, added a new sound to be on the alert for.
It IS the UAS pilot's responsibility. See the regulation cited in post #43.
If a collision is imminent, the manned aircraft pilot would be bound to try to avert it. But the primary responsibility is on the UAS pilot. UAS pilots are required to other aircraft give way in all situations.
I wonder how good it feels to have right of way in your cessna 172 or Ft Lewis blackhawk, while a drone comes through your windshield at 210 MPH?
Max cruise airspeed on a 172 is 124 kts. Max airspeed is 163 kts. So, at cruise the drone would have to be going 67 mph at 180 degrees to your course to have that closing speed. My Mavic 3 tops out at 47 mph. What are you flying?
I think you're pointing out that the manned aircraft pilot should be vigilant for potential collisions. That's true. But the bottom line legal responsibility is always on the drone pilot.
It absolutely was 500-something feet when I first checked Flightradar24, and ascending fast. By the time I managed to take a screen snapshot on my mobile phone it had ascended to 975 feet.
Oddly enough the helicopter did a U-turn right near my house, and when it was nearest I can tell you it was at 500-something feet. Almost like they came from San Francisco just to check me out if you look at the entire flight path. I took the photo of the helicopter when it was near the blue dot (me) and the screen snapshot from Flightradar24 as you can see was after it had turned and was climbing.
How does FlightRadar24 define barometric altitude? I'm unable to find an answer, but it's not instantaneous AGL altitude. I'm guessing it's standard altitude based on 29.92 in Hg. If your local elevation is significant, the helo could have been very low to the ground, even with the 975' barometric altitude as illustrated.
According to What is my elevation?, my elevation is 443 feet. What insight does that give you into the accuracy of the reading?
According to their website:
AMann
Well-Known Member
The information on FliteRadar24's website on that altitude reading is useless in figuring it out. Barometric altimeters need to be set to a reference pressure. Above 18,000' the FAA says to use standard barometric pressure, 29.92 in hg. For local flights, it's usually set to whatever value makes the airplanes altitude 0' when it's on the ground at the airport.
Fliteradar24 just says that the altitude is whatever is reported by the aircraft's ADS-B transponder. I'm not familiar enough with ADS-B to know what barometric reference they use.
If you're standing at 443' MSL, and airplane reporting its altitude as 448' MSL flew over, it would hit you square in the face.
I'm really curious about what the Fliteradar24 barometric altitude readings really represent. Anyone? Any current Part 61 pilots know?
We get a lot of medical choppers here, with some occasional low military traffic that doesn’t show up on ADS. Luckily most of the military aircraft are around 2000’, most of the time.
I just skimmed through the FAAs' Barometric Altimeter Errors and Setting Procedures and would assume the barometer was calibrated properly. It does seem strange to me that the reading was 500-something feet because you're right, it would be crashing into trees. It was quite low though. The reading of 975 feet in my screenshot minus my altitude of 443 feet would give an absolute altitude in the 500s of feet. Maybe it was really low when I saw the reading in the 500s but I don't remember whether it was 501 or 599 feet. If it was closer to 599 feet, and I'm at 443 feet, it would have been 160ish feet absolute altitude, which could well be possible. It was really loud and low.
I agree it doesn't quite add up though.
Similar threads
