distance between plane & building

[mhubert]

hi

I leave near Sydney airport in a residential tower close to the airport at Erskineville. While it's a planespotter's dream, some days planes seem to come by quite close. Anyone know what the Australian legal minimum distance is between a building & a plane?

thanks

 

[markis10]

246 ft or 75m is the minimum obstacle clearance on a Cat 1 ILS approach I believe, occasionaly you will see lower when they are testing the navaids and recertifying them (usually Super King Air B200/B350 aircraft from AeroPearl on contract to Airservices doing many go arounds and making the controllers work for their money ).

 

[mhubert]

246 ft or 75m is the minimum obstacle clearance on a Cat 1 ILS approach I believe, occasionaly you will see lower when they are testing the navaids and recertifying them (usually Super King Air B200/B350 aircraft from AeroPearl on contract to Airservices doing many go arounds and making the controllers work for their money ).

thanks - I meant horizontal distance, not vertical/height

 

[markis10]

thanks - I meant horizontal distance, not vertical/height

No problems, its 10 degrees from the centreline of the runway.

 

[mhubert]

No problems, its 10 degrees from the centreline of the runway.

sorry, let me try another way. My building is 18 stories high. If I look out my window a plane comes by at the same height I am. How close can it be to my building, ie 200 metres, 500? If I were to measure the distance from my window to it as it goes past.

cheers!!

 

[possumoz]

I say that if a FA asks you to return to your tray to its original position and fasten your seatbelt there's a fair chance its too close
(sorry its Sunday and I'm stuck in a dingy hotel(works paying):-|

 

[markis10]

sorry, let me try another way. My building is 18 stories high. If I look out my window a plane comes by at the same height I am. How close can it be to my building, ie 200 metres, 500? If I were to measure the distance from my window to it as it goes past.

cheers!!

It depends on how far you are away from the runway, thats why said 10 degrees from the centrline as the clearance area radiates from the centerline out at a 10 degrees angle, at 500M from the threshold thats not a great deal far away, at 5 KM its a lot more.

Lateral separation or clearance zones for approaches are measured in degrees rather than a set distance as this represents the possible navigation tolerance more accurately than a flat distance limit.

The 13 approach at Kai Tak was a good example of how close aircraft may get to buildings laterally and vertically.

 

[QF WP]

Based on markis10's responses, I think I can "see" but can't explain it - so I went to Wikipedia. On the approach plate, is the shaded area (running right to left, expanding from the runway the further it goes away) basically what you are saying markis10 :?:.

If so, then wha I thinkt markis10 is wanting to know mhubert, is how far from the end of the runway and at what angle, is your building ? Then somebody can probably give a more accurate calculation (someone with more advanced mathematics than me ).

 

[2muchplastic]

It's a fairly simple calculation using sin or cos depending on which measurements you have.
If you can imagine that the "no entry" area relative to the centre of the runway is like a right angled triangle. (See the diagram here Right Triangle Angle And Side Calculator). So your building's position is at angle B, and the length of the side c is the distance from centreline at the end of the runway. If for example your building is 5000m in a straightline from the centreline (sticks 5000 in the side c box), and we know that angle A is 10 degrees (sticks 10 in the Angle A or B box and clicks Calculate button), it calcluates that side a is 868m.

So that should be the minimum distance between you and the plane, at that distance.
I'm not sure that I've explained that very well, but I'm sure you'll know what I mean.

 

[markis10]

Think of it as a funnel with the point end at the runway!

 

[QF WP]

Thanks 2muchplastic, well explained (I could understand it anyway). Year 12 Maths I subject was a looong time ago and I've had no need to use those calculations since. I'm sure the OP will be able to use the information to make their own calculations.

It's a fairly simple calculation using sin or cos depending on which measurements you have.
If you can imagine that the "no entry" area relative to the centre of the runway is like a right angled triangle. (See the diagram here Right Triangle Angle And Side Calculator). So your building's position is at angle B, and the length of the side c is the distance from centreline at the end of the runway. If for example your building is 5000m in a straightline from the centreline (sticks 5000 in the side c box), and we know that angle A is 10 degrees (sticks 10 in the Angle A or B box and clicks Calculate button), it calcluates that side a is 868m.

So that should be the minimum distance between you and the plane, at that distance.
I'm not sure that I've explained that very well, but I'm sure you'll know what I mean.