douglcobb

I need to give an AGL of a location to a contractor. It is my understanding the AGL is relative to your alititude. So there isn't a "set" AGL for a specific location is there? It all depends on your alititude.

Flying 2000 ft above a hill that is 500ft then your agl would be 1500ft?

TankerBob

AGL = Above ground level

So your equation is correct if you are standing on top of a hill that is 500ft above sea level and someone was to fly over your head at 2000ft above sea level (ie reference used in aviation) then they would be 1500ft AGL.

douglcobb

so pretty much If someone asks "give me the AGL of location x?" its impossible without them telling you how high they are flying.

Used for safety applications eg. you are 500 ft alititude and look down at your map and see a 800ft mountain your screwed because you are -300 agl.

jasonwb

are they wanting to know how high a specific point is on the ground? if that is the case, then you would give them an MSL alt. i.e. the alt. you are at above sea level... not sure if i really understood the question.

if that is what they want, find you a sectional chart and find some points on the map close to where you are looking at and there will be MSL altitudes on the chart.

hope i helped a little

Jb

250 or point 65

INcorrect. Flying 2000 ft above a hill is 2000 Above Ground Level.

There is no simpler way to put it. If you are 6 ft tall, the top of your head is 6 ft AGL...no matter what ground you walk on (as long as you're standing up). If you are standing on a beach, hill, mountain, plains, doesn't matter. However the top of your head in MSL is the elevation of the ground, plus 6 feet.

Intheairtonight

Normally they will ask you the altitude. Give the altitude above MSL and confirm the QNH you are using if in any doubt. That should do it.

HercDriver130

bingo!!!! Shame on you tanker bob...

RAHPilot5

flying 2,000 feet above a hill = 2,000 feet above a hill.

If you jump 10 feet in the air, how high are you above the ground? ok now its 90 degrees outside and you jump 10 feet in the air, how high are you now?

you smoke an ounce of chronic and jump 10 feet in the air, how high are you now? <trick question>

TonyC

It seems to me the original poster got the concept correct, but the semantics incorrect. Oh how folks will rail when their grammar is corrected, but oh how difficult it can be to communicate when it's not correct.

"Flying 2000 feet ..." How do we fly at an altitude of 2,000'? Why, we set the local QNH in our Kolsman window, and we peg the needle at 2,000. Thusly, we cruise at a height of 2,000' above Mean Sea Level.

"... above a hill ..." Well, hopefully we're always flying above something. Whether it be a hill or a valley, a mountain or a canyon, a butte or a prairie, a river, pond, lake, or ocean, we always want to be above it unless we're taking off or landing. (It could be argued that even then we're above it, but we're certainly not below it.)

"... that is 500 ft ..." We typically measure elevations on the earth in terms of height above mean sea level, so there we are at 2,000' MSL above a hill that is 500' MSL.

"... then your agl would be 1500ft?" That seems like correct math to me. 2,000 - 500 = 1,500, and the difference between the two MSL altitudes is, in this case, the AGL altitude.


So, sounds to me like we get an A for the science part of the problem, and a C- for the English part.


I offer this as a correction:

Flying at an altitude of 2,000 ft MSL over a hill, the elevation of which is 500ft MSL, then your altitude AGL would be 1,500ft.




Don't read what he wrote, read what he meant.






.

__________________
- TonyC


The truth only hurts if it should.