how to find elevation for an uncertified ALA?
how to find elevation for an unknown ala?
is there a way before im even up in the air? as i can find the density by using the declared density chart in the CAO however how would i use this data for TDR/LDR in the poh |
Use Google Earth for the approximate height, declared density should be conservative but dont count on it
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For an approximation, Google Earth.
Draw a "Path" (Add -> Path) from somewhere at sea level to your intended destination and hit Edit -> Show Elevation Profile. Tools -> Options to change it to feet if you desire that. In the air, part of the fun I remember during PPL navigation exercises was a diversion to an unplanned airfield. You should get a feeling for circuit heights and standard circuits so that even navigating to a unplanned airfield you can judge the circuit height and therefore approximate the airfield height even without any other information and then get ready for your ALA inspection. |
Whats wrong with getting the Elevation off a WAC chart? That's if you have one !!!!!
Groggy |
Here's a novel idea!
What about using the contours and spot heights from the WAC! Ooops, Groggy beat me to it.. |
Groggy :ok:
is there a way before im even up in the air? Otherwise I did not understand the question. |
Jabba is correct.
Don't land anywhere unless you have prior permission (preferably written) and this permission should include your required details. I once was almost fined 10 ($5,500) demerit points by our friends at CASA for almost landing at an ALA without permission (I didn't touch down). I did have permission but it was not from the appropriately authorized person. From now on, it's written permission or an SMS as a minimum. |
the known unknown...
Overfly this unknown ala...presumably your altimeter is on area QNH....at an estimated height above the field 1000'. If yr cruising at 3500' then... you have yr answer.
Once you have landed..with prior permission...check the altimeter reading and see how good yr guestimate of height above ground was. Of course ala ht. will be a close approximate as area QNH may differ slightly from the actual ala QNH Before flight ?....Captn Fathom has a good idea.:ok: |
From now on, it's written permission or an SMS as a minimum. |
Groggy, as if...WAC charts cost money!
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Free 1:250 topos
Geoscience Australia have online free 1:250k topo charts. www.ga.gov.au
Contour lines too! If you have HEMA maps app on your iPad you can download it on there too. |
as i can find the density by using the declared density chart in the CAO however how would i use this data for TDR/LDR in the poh So, take the density altitude (DALT) you derived from the CAO charts, and use the ISA model to convert it to a set of PALT and temperature numbers. Don't forget to add the elevation to the DALT value obtained from the chart. A DALT of 2,000' for example, would be a PALT of 2,000' and temperature of 11 degrees C. |
From now on, it's written permission or an SMS as a minimum. You probably dont land at very many places then. |
93 Protection of certain rights Nothing in these Regulations shall be construed as conferring on any aircraft, as against the owner of any land or any person interested therein, the right to alight on that land ... . |
Back to how to find the elevation for an unknown ALA....
Method 1) Take a bag of flour and whilst flying over the ALA chuck it out the window (this works best in high wing aircraft) carefully measuring the time it takes to hit the ground (some sharp manoeuvring may be needed to get good visibility of the drop zone). Using the formula d = 1/2gt2 you can subtract the distance covered by the bag of flour from the altitude indicated on the altimeter and you should have the AMSL of the airfield. |
Jabba is correct. Don't land anywhere unless you have prior permission (preferably written) and this permission should include your required details. I once was almost fined 10 ($5,500) demerit points by our friends at CASA for almost landing at an ALA without permission (I didn't touch down). I did have permission but it was not from the appropriately authorized person. From now on, it's written permission or an SMS as a minimum. You may not have a right to land somewhere without permission, however that is very different to it being a criminal offence under CARs/CAOs to land somewhere without permission. |
There is something enormously satisfying (for me) in scoping out a piece of real estate in the wilderness then landing on it. I never ask permission, who would I ask? This is a hugely popular sector of aviation in the USA, with several web sites devoted to it and an FAA publication specifically written about it. In Australia it seems frowned upon and there is very little interest in the subject.
Sometimes I use Google Earth, sometimes I just scope it out from the air. My only requirements is that there is something interesting to do when I land, either camping, fishing or just sightseeing. Axiomatic to these operations is of course a STOL aeroplane and suitable tyres. It is my belief, although I admit to no research, that this is perfectly legal as far as CASA goes, there only remains the subject of land holder permission. Given that the land I use is mostly public land anyway, way outside the public eye, why would I even ask? Given our good ole Aussie semantics, the answer would never be yes in any event. |
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