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Guest kavan2

Approach question

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How do you fly a an approach if it is IFR conditions and poor vis where there is no ILS or localizer. How do you line up for the runway and know if you are on the correct glide slope and on course for the threshold? Is it just quess work?kavan

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Hi,2 options:1. If another runway has an ILS, you *may* do a circling approach if conditions allow.2. Divert to another airport

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This is called a "non precision approach". You will need the charts for the airfield you are landing at. If there are no NavAids (VOR, NDB, DME) available and the airfield in question has visual approaches only, then the airfield should generally not be used under IFR conditions.A non precision approach is flown using a DME (Distance Measuring Equipment) and an approach plate (chart) for the runway in use. You would tune your NAV1 radio to the frequency of the VOR on the chart. At the bottom of the chart there will be a glideslope diagram telling you the altitude you should be flying at for a given distance from the DME. Say for example 3000ft at 10nm from the DME, 2000ft at 6nm from the DME and then 800ft at 2nm from the DME. If you are at these altitudes when the relevant number comes up on your navigation display, you will be roughly within the limits of the glideslope.Lining up with the runway is done in a similar fashion. On your chart you will be given radials (directions to a VOR) to fly on from a specified VOR/VORs which you will tune into your NAV radio. Fly in the given direction and you wont be far from the centre line when you get the airfield in site.A bit complicated and long-winded but I hope this helps.

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This guys is what pilots get paid for :DThe real answer is that that there are many ways of transitioning from IFR/IMC to visual sighting of the runway and safely positioning of the aircraft to land.As an example of some of teh types of Runway Aligned and Circling Approaches:ILS, VOR, NDB, LOC, VOR/DME, NDB/DME, VOR/LOC, NDB/LOC, DME HOMING and DESCENT, GPS NPA, PAR and plenty more combinations.What's more- you have to be able to do any and all of them in crap weather, on one engine and with systems failures .. sound like fun? It is!:DRgds,

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yes thanks for the explainationkavan

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i have to say that it still seems a little bit haphazard even this way as the vor's are never usaully in line with the runway or at the touch down point but off to the side somewhere.kavan

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Kavan, it may appear haphazard, but the published minima for the approach takes this into account. They will always be higher than if it were a full blown ILS. At a published distance/height, if you don`t see the runway or runway lights, you do a missed approach.Also, quite a few ILSs are not perfectly aligned with the runway either, again this is reflected in the minima.Kjell.

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Hi Kavan,Not all airports are at places where terrain allows a long final leg as offered on an ILS. Also ILS equipment is expensive to install and maintain and so some places go for cheaper options. If you really have doubts fire up Teamspeak or meet me on MSN and we will have a chat about it but I assure you there is nothing haphazard in the world of the professional aviator... apart from the quality of the coffee :-grnmd

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When it comes to the world of big airliners and bigger airports it seems easy to be a pilot. The hardest approach in the world is single pilot IFR in a light plane with nothing but the basics. Flying an ILS is childs play compared to flying an NDB alpha approach to minimums. Despite the rather deceptive title of non-precision, they require a degree of concentration and precision that is not needed with an ILS. At KALB in upstate NY, Southwest Airlines uses runway 28 a lot. This is a VOR and GPS approach and they do it in some miserable weather. You can't always get an ILS. This is why you learn to do all those different approaches as an instrument student. You may also run ito one of those days when the glideslope is out and you have no choice but to do a localizer only approach. This is why they have pilots in the cockpit and not just FMCs. Bob K.

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Check the forum below, Called "FS2CREW". That is a software for PMDG only and it supports the First officer, but also when the RVR is very low and low visibility procedure is in use how to handle it.

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Another type of approach to a runway is either a Precision Approach Radar(PAR) or Surveillance Radar Approach (SRA), they are both talk down approaches. The approach controller will give guidance on the final approach track via heading changes and in respect of the PAR, will be able to check whether the airplane is above/below the glideslope. The SRA works in a similar manner, in that he approach controller will give headings to the pilot to maintain the final approach track, but will only give altitide/height checks to the pilot every 1 or half a mile from touchdown. Again as previuosly mentioned, the minumum decent altitude/height will be much greater than say using an ILS.Hope this helps a little.CheersSteve

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