B747forever
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How Far Away Can One See From A Aircraft?

Sat Jun 12, 2010 7:57 pm

I am sorry if this is not the right forum for this thread.


Let's say that a aircraft flies at FL380 on a clear day how far away can one see from the aircraft. Also if one is on the ground how far away (distance) from where the aircraft is can you see it?
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Viscount724
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RE: How Far Away Can One See From A Aircraft?

Sat Jun 12, 2010 9:36 pm

Here's a calculator which should answer your questions. Just plug in the altitude to obtain the approximate distance to the horizon.
http://www.ringbell.co.uk/info/hdist.htm
 
B747forever
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RE: How Far Away Can One See From A Aircraft?

Sat Jun 12, 2010 9:50 pm

Quoting Viscount724 (Reply 1):



So when a airplane cruise at FL380 one can see about 239miles away and the airplane can be seen by people on the ground 239miles away.
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Bellerophon
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RE: How Far Away Can One See From A Aircraft?

Sat Jun 12, 2010 10:32 pm

Viscount742

An interesting and useful little calculator - thanks for posting the reference - I've been playing around with it.

Cruising at max altitude, on my latest aircraft type, the horizon is 28 minutes flying time away.

Cruising at a much higher max altitude on a previous aircraft type, the horizon was only 14 minutes flying time away! 

Best Regards

Bellerophon
 
timz
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RE: How Far Away Can One See From A Aircraft?

Sun Jun 13, 2010 12:03 am

If you're looking at Mt Shasta from FL 380 over the Central Valley it should be visible from at least 300 miles. Roughly, distance to the horizon from Mt Shasta, plus distance to the horizon from FL 380.
 
j0rdan
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RE: How Far Away Can One See From A Aircraft?

Sun Jun 13, 2010 12:27 am

Another formula you can use is:

Distance seen in miles = 1.23 (X) square root of altitude in feet

Jordan
 
timz
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RE: How Far Away Can One See From A Aircraft?

Sun Jun 13, 2010 9:06 pm

That's distance to the horizon, with some allowance for refraction.
 
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TS-IOR
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RE: How Far Away Can One See From A Aircraft?

Sun Jun 13, 2010 9:23 pm

When you are FL380 the horizon is 239NM away, but people on ground won't see you when you are 239NM from their vertical. The maximum i have ever seen from ground is contrails from approx. 80NM.
Next flight TUN-YUL Tunisair A330-243.
 
Arniepie
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RE: How Far Away Can One See From A Aircraft?

Sun Jun 13, 2010 10:01 pm

AFAIK, the answers are incomplete, for instance you can see farther on the poles vs the equator due to the shape of the earth, also air temperature changes the light behaviour properties.
I remember reading somewhere that on a cold ,clear winterday some mountains on iceland can be seen almost from 400 miles away on cruising altitude. (IIRC)

[Edited 2010-06-13 15:02:55]
[edit post]
 
xero9
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RE: How Far Away Can One See From A Aircraft?

Mon Jun 14, 2010 12:47 am

Quoting Arniepie (Reply 8):

Soooo in other words, you can't know for sure how far, but either way we can agree it's pretty far!
 
SlowFly
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RE: How Far Away Can One See From A Aircraft?

Mon Jun 14, 2010 7:55 pm

Some useless knowledge: a quick rule of thumb for radio line-of-right calculations is to pretend the earth's radius is 1.33 bigger than actual. Due to diffraction.
 
cobra27
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RE: How Far Away Can One See From A Aircraft?

Mon Jun 14, 2010 8:55 pm

Quoting TS-IOR (Reply 7):
When you are FL380 the horizon is 239NM away, but people on ground won't see you when you are 239NM from their vertical. The maximum i have ever seen from ground is contrails from approx. 80NM.

True. No way you can see 240 miles
 
timz
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RE: How Far Away Can One See From A Aircraft?

Mon Jun 14, 2010 9:53 pm

I've seen contrails 170+ miles away (747s making the turn over the Avenal VOR, seen from the hill above Berkeley, California). If I were standing on a higher mountain, with clear air and low sun backlighting the contrail against a fairly dark sky, 240 miles would be no problem with 10x binoculars.

http://www.jstor.org/pss/208390


[Edited 2010-06-14 14:54:36]

[Edited 2010-06-14 14:57:05]

[Edited 2010-06-14 14:59:20]
 
AncientPelican
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RE: How Far Away Can One See From A Aircraft?

Tue Jun 22, 2010 5:20 pm

I recall a TWA transcon heading westbound one evening where the pilot came on and said the people on the left side of the plane could see the lights of St Louis while those on the right could see Chicago.
 
unattendedbag
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RE: How Far Away Can One See From A Aircraft?

Tue Jun 22, 2010 5:29 pm

Quoting B747forever (Thread starter):
Let's say that a aircraft flies at FL380 on a clear day how far away can one see from the aircraft.

On a clear day, you can sometimes see the moon, and that's more than 238,000 miles. If it's dark outside, then you can usually see the stars.

[Edited 2010-06-22 10:31:32]
Slower traffic, keep right
 
rolypolyman
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RE: How Far Away Can One See From A Aircraft?

Fri Jun 25, 2010 11:54 am

I recall one night on AA in November 1996 we were at FL390 on a leg from the AEX to FZT VOR into DFW. I've been all over Texas and know the layout of cities like a map, and that's just what I was seeing with it being a particularly clear autumn night with city lights painting out the location of everything. Just before starting our descent I recognized our position as being just north of Nacogdoches. From that location I was able to easily distinguish the city lights of Waco, Temple, Austin, College Station, and Houston all at once. On the distant horizon I could distinctly see a nebulous but bright pancake smear of San Antonio, which was about 220 nm from where we were.

That was an amazing sight as I was seeing territory in one single glance that took many hours to traverse by car. It was almost like being in space. One of my best memories while flying, and definitely the furthest distance I can ever recall seeing from the air.

[Edited 2010-06-25 04:56:20]
 
nomadd22
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RE: How Far Away Can One See From A Aircraft?

Fri Jun 25, 2010 5:21 pm

Diffraction will only add about 40 miles to the distance of the horizon.
If you're flying around Tibet, all things considered, you should be able to see Everest peeking over the horizon at close to 500 miles.
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