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Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 8:15 pm
by townleyc
I thought it was the fixed costs of running an aircraft :?

KE

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 8:25 pm
by Ibra
You can use 1nm/300ft or 3nm/1000ft to get an idea about how many degres they are above/bellow the horizon, about 3deg, usually an interesting traffic will be in those ranges

+/-15deg from the horizon, the one bellow can't climb to hit the one above unless it's an F16...

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 8:26 pm
by Dave W
lobstaboy wrote:OK, so how exactly do we define "overhead"?

The runway is below you.

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 8:46 pm
by lobstaboy
Dave W wrote:
lobstaboy wrote:OK, so how exactly do we define "overhead"?

The runway is below you.


Exactly below you? That doesn't work - if I'm doing an overhead join and flying at right angles to the runway then I'll be no longer overhead by the time I've finished saying "G-CD overhead".
If it's Royston that I'm overhead then I guess I could be anywhere in an area of about 10 sq miles and still have Royston or some part of it beneath me.
And so on...
FTAOD my point is that "overhead" is necessarily an imprecise term and we shouldn't expect it to be otherwise.

The village of Over in Cambridgeshire is quite small so it's quite a challenge to be able legitimately to make the call "I'm over Over, over." But it's a good use of Safetycom ;)

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 8:59 pm
by Dave W
"1 mile East of Over" will do it. What you are doing is cueing people's eye to you.

With reference to a geographical feature in "the open FIR", within a mile is useful.

Over an airfield ,(i.e. OHJ) the traffic density is likely much higher so a mile or so off is going to be too coarse.

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 9:20 pm
by Cessna571
lobstaboy wrote:If it's Royston that I'm overhead then I guess I could be anywhere in an area of about 10 sq miles and still have Royston or some part of it beneath me.
And so on...
FTAOD my point is that "overhead" is necessarily an imprecise term and we shouldn't expect it to be otherwise.



Agreed, but if you call overhead Royston, you shouldn’t be 4 nm north of it.

You should at least be overhead a bit of it !

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 9:40 pm
by leiafee
This distance to the horizon calculator is fun to play with although vis usually makes it a moot point!

http://www.ringbell.co.uk/info/hdist.htm

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 9:55 pm
by Ibra
leiafee wrote:This distance to the horizon calculator is fun to play with although vis usually makes it a moot point!

http://www.ringbell.co.uk/info/hdist.htm


Surely it's for Class 1 holders with no restrictions? not some Class 2 bunch like me with VDL in section XIII or those who fill PMD with 500% zoom on CAA website :lol:

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 10:55 pm
by T6Harvard
leiafee wrote:This distance to the horizon calculator is fun to play with although vis usually makes it a moot point!

http://www.ringbell.co.uk/info/hdist.htm


Ooh, thanks for that link @leiafee .

Re: Judging distances in the air

PostPosted:Thu Jun 10, 2021 11:11 pm
by Paul_Sengupta
Dave W wrote:
lobstaboy wrote:OK, so how exactly do we define "overhead"?

The runway is below you.


Not that the airfield is below you?

lobstaboy wrote:The village of Over in Cambridgeshire is quite small so it's quite a challenge to be able legitimately to make the call "I'm over Over, over."


How does the QXC route go...Over, Andover and Dover?

Re: Judging distances in the air

PostPosted:Fri Jun 11, 2021 9:47 am
by kanga
Ibra wrote:..
+/-15deg from the horizon, the one bellow can't climb to hit the one above unless it's an F16...


.. or, I've been told, a hot air balloon (whose pilot can definitely not see what's directly above) :wink:

Re: Judging distances in the air

PostPosted:Fri Jun 11, 2021 10:45 am
by gaznav
When I had 6/4 distance vision the maximum I could see a light aircraft was at about 3nm, a Hawk sized aircraft at about 5nm and a tanker at about 10nm. That was using an air to air RADAR to que my vision and get an accurate range.

These days I am 6/5 on a good day and 6/6 on a bad day as I approach my 55th birthday and I need readers for n6 close in work. So my eyes are definitely worse. So I can probably knock 20-25% off of those distances now. :cry:

Which is also why I believe that EC for GA outside of about 8nm for air-to-air detection is pretty pointless. I try to think of my aircraft flying in an 8nm bubble and +/- 6,000ft. Outside of 8nm then I am highly likely to see it as it will be chuffing HUGE, and inside that if I haven’t spotted it then I want to know about it. Anything outside of that is just an unwanted annoyance in my personal opinion and likely to distract me unnecessarily. :thumright:

Re: Judging distances in the air

PostPosted:Fri Jun 11, 2021 11:47 am
by Highland Park
Cessna571 wrote:
lobstaboy wrote:If it's Royston that I'm overhead then I guess I could be anywhere in an area of about 10 sq miles and still have Royston or some part of it beneath me.
And so on...
FTAOD my point is that "overhead" is necessarily an imprecise term and we shouldn't expect it to be otherwise.



Agreed, but if you call overhead Royston, you shouldn’t be 4 nm north of it.

You should at least be overhead a bit of it !

It was drummed into me by Gerry Honey that your position reporting, especially in the circuit should be as accurate as possible for the benefit of the situational awareness of others. Even now, it really irritates me when an aircraft calls "Final" when they are still late base leg, about to turn onto final approach. I see it frequently when I'm the AGCS operator and its unhelpful, particularly when we have students in the circuit.

Ian

Re: Judging distances in the air

PostPosted:Fri Jun 11, 2021 1:28 pm
by kanga
ISTR ex-FJ AEF Chipmunk pilots seemed often to call Final when starting a continuous curved descent from the end of downwind :roll: Perhaps this was legacy of curved pfl pattern via Key procedures.

Re: Judging distances in the air

PostPosted:Fri Jun 11, 2021 2:03 pm
by Ibra
kanga wrote:
Ibra wrote:..
+/-15deg from the horizon, the one bellow can't climb to hit the one above unless it's an F16...


.. or, I've been told, a hot air balloon (whose pilot can definitely not see what's directly above) :wink:



They need mirrors :lol:

Apparently, they like close encounters: at least they can sell some entertainment to their bored tourists !

While crossing near Ragley Hall on a late evening, we decided to call RT on their shared Balloon frequency, one of them asked if I can do a pass nearby for his pax to take pictures :shock:

It did come to my mind that I should keep some distance from the guys, you know to avoid receiving that letter from Aviation House, Gatwick with "Re: regarding the unofficial airshow" in the title :pale: