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WilloW_737

VOR landing question - runway not in alignment - correct proceedure ?

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Hello;

 

This example relates to Coffs Harbour, NSW, Australia. VOR RWY 21 Approach.

 

The chart indicates runway alignment at 222 degrees. In addition to the to VOR, the airport also has an NDB that matches the position of the VOR.

 

Aligning the VOR and NDB at 222 degrees beings the aircraft into visual contact with runway 21, however, the aircraft is always to the left of the runway alignment.

 

I realize VORs are non precision, but I am wondering if this is normal? Does the off centre arrival indicate that the VOR is to the left of the runway?

 

I want to ensure I am doing the approach correctly.

 

VOR CH 117.00, NDB 311, YSCH RWY 21, Approach course 222 Degrees.

 

Thank you, Iain

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Thanks - I thought so, but wanted to double check.

 

VOR approaches are visual & from recollection the Polish accident was not VFR. Cheers, Iain

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Very common with non-precision approaches. Basically designed to throw you out of cloud and have the runway somewhere in front of you.

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Sorry, but

 

A VOR/NDB approach is always a little offset. That's why the TU-154M of the polish president (R.I.P) crashed in smolensk two years ago.

 

Totally wrong, and

 

VOR approaches are visual & from recollection the Polish accident was not VFR. Cheers, Iain

 

Totally wrong #2.

 

 

Now, in general:

 

Not all VOR approaches are offset, although many, if not most, are. Usually you would be crossing the centerline at about the same time as you would be crossing the MDA, so you can just turn to final and go on. However you can align yourself to the runway whenever you feel like it, and can see the field.

 

Regarding Totally wrong #2:

VOR approaches are NOT visual! There is a reason they are called non-precision instrument approaches. Now, last part is visual, but that can be said about every approach down to CAT II ILS, precision or non-precision.

 

Polish AF Tu-154M being IFR or VFR has nothing to do with it.

 

Regarding Totally wrong #1:

 

a) Not all non-precision (VOR/NDB) approaches are offset. Incidentally, Smolensk configuration is a good representative of this. Smolensk has a rather common (in the East) configuration of two NDBs in extended runway centerline, meaning that in horizontal plane, you keep your needles on the same/opposite direction, depending if you are in front or between the beacons. VERY easy to fly. Alas, vertical plane is a bit trickier.

 

B) Apparently, since the approach was not offset, the plane did not crash because the approach was offset. Now, the vertical plane of an approach over two radio beacons.

The beacons are, apparently, positioned at known position regarding airport. Therefore, you can determine your required altitude over each of them. In absence of other help, like DME or PAR, you will have to manage your descend in a way, such so that you will begin descend at a predetermined rate exactly as you fly above the outer beacon. You should then have a known altitude above inner beacon, if you dont, there is a mistake somewhere.

Still, skilled pilot can safely fly this type of approach down to 100m ceiling/1km visibility.

 

Now, the mistake Polish pilots did, is, they did not descend to minimum altitude according to barometric altimeter, but according to radio altimeter. Since there was a valley in front of runway (as much as 50m under airport level), descending to low level according to RA actually made them descend under airport level. Then they hit the hill leading to the airport.

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Approaches can be offset by 30 degrees before they need to be considered not "straight in."

 

Even ILS can be offset. . . up to 6 deg, IIRC. (It's been a while since my CFII days.)

 

After that, it gets a lot more fun.

 

Try the LDA-8 PAJN.

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Thank you for everyone's replies.

 

As for "visual" I was referring more to be able to see the runway lights from a distance, rather than CAT 3 autoland in limited visability. A VOR approach is definitely an instrument approach and not a visual approach - I should not have used the "visua;" word :)

 

Cheers, Iain

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Now, the mistake Polish pilots did, is, they did not descend to minimum altitude according to barometric altimeter, but according to radio altimeter. Since there was a valley in front of runway (as much as 50m under airport level), descending to low level according to RA actually made them descend under airport level. Then they hit the hill leading to the airport.

 

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BRGDS Peter

Probably thinking of another accident here but i seem to recall the pilots putting the wrong imputs in the fmc, since of a change of rwys given to them by atc and they got lost and manged to get them selves on the wrong side of the valley of the airport, for a visual approach to the rwy and they slammed in the hill as well.

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Probably thinking of another accident here but i seem to recall the pilots putting the wrong imputs in the fmc, since of a change of rwys given to them by atc and they got lost and manged to get them selves on the wrong side of the valley of the airport, for a visual approach to the rwy and they slammed in the hill as well.

 

The TU-154 does not have an FMC, and thus you must be thinking of another incident. Can you remember an airline or craft type?

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The TU-154 does not have an FMC, and thus you must be thinking of another incident. Can you remember an airline or craft type?

 

The Polish one did, the Slovak both do, and also some more ex CSA, Slovak Airlines etc. They call it Tu-154M-100 IIRC and it had UNS-1 FMC and some more Western extras, from Honeywell I believe.

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on the fmc equipment options page make sure you set fsx loc course enabled the ngx will automatically set the ils course for you using the data from the fsx database as a guidline ensuring the that you are alwasy on the correct approach path. its something to do with the magnetic variation, fsx does not support this change over time

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The Polish one did, the Slovak both do, and also some more ex CSA, Slovak Airlines etc. They call it Tu-154M-100 IIRC and it had UNS-1 FMC and some more Western extras, from Honeywell I believe.

 

Thanks for the info, I was unaware of that. The FMC seems kind of small, something similar to what you might find on, say, a Dash-8, for example.

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