What is an obstacle free zone ?
 

Hi Guys,

I was just wondering what was an obstacle free zone at an Airport ? The
ICAO definition is far too complicated and I quote- The airspace above the
inner approach surface,inner transitional surfaces, and baulked landing surface and that portion of that strip bounded by these surfaces,which is not
penetrated by any other obstacle other than a low mass and frangibly mounted one for navigation purposes.:ugh:

Are these depicted on Approach charts? Could anyone please enlighten me
using simplistic phraseology.

They're not depicted on the Approach or SID charts, but both of these charts use the "obstacle free zone" extensively. All procedures are designed to keep you above the planar areas defining the lower limits.

In simple terms, the obstacle free zone is the area above a series of planes, horizontal and at a gradient, the lower limit of which is defined by obstacles.

OLS charts (Obstacle Limit Survey, not available to pilots and jealously guarded by airport surveyors), define these very clearly. If the obstacles are not too critical, these are very useful in designing Engine Failure Special Procedures, which have a significantly lesser obstacle clearance criteria than does PANS-OPS.

OzExpat, where are you?

Regards,

Old Smokey

.. jealously guarded by airport surveyors

.. not if you ask nicely .. and, occasionally, pay a few dollars ...

I mustn't have your smooth talking ways John_T, but the guys in Brisbane are bloomin' marvellous.

The best free deal that I ever had was a full computer programme down-load for an FMC (No names) in exchange for a company baseball cap and T-shirt, and then my boss wanted a written report on why I was giving away company property...:uhoh:

Regards,

Old Smokey

Ooooooooooooooh! Was that for a 777 FMC? Can I have one please, please, please. Pretty please ........

UK, refer to:

http://www.caa.co.uk/docs/33/CAP168.PDF (2.83 MB)

Chapter 4, 8.0 onwards.

Think of the OFZ as the place where you would least like to hit anything, i.e glide slope, runway, 50ish mtrs either side of C/L.

Also helps the ILS and Localiser operate .