ILS failure

[Nicholas49]

Hi,

Not sure if this is the right forum for this question, but here goes

Just completed my PPL and hoping to move on up the ladder.

I've been reading up on ILS approaches. As you can imagine, ILS is a whole new ball game and I'm very new to it.

ILS seems to be an excellent system for precision approaches - almost too good to be true in fact.

But my question is this: does it ever fail? And what happens if it does fail, the weather conditions are terrible, you are flying a large, full passenger jet and are at 500ft? Is there a back-up system?

Now, perhaps these things don't happen, but I'm interested to know how you get out of a situation like this if they do!

Nick.

[littco]

Most aiports that have an ILS will have some other form of approach but this most likely it is going to be non precision, such as a VOR/DME or an NDB, However if the weather is below your minima for the non precision approach then you are more than likely going to have to divert. Of course if you're on an ILS approach and it fails, you would have to initiate a go around and then decide what to do.

[CAT3C AUTOLAND]

There are also standby transmitters for ILS approach systems. Failed and downgraded equipment is usually listed in the operations manual in to what you can accept. It also depends on the type of approach you are flying, i.e. CAT1/2/3 etc.

Hope that helps.

[airman13]

Nicholas49,

actually the backup systems are VOR/DME ,NDB etc.According to my company if you are performing an ILS app and any malfunction occurs (ground or a/c systems as well), below 1000ft AGL, and no visual contact , you have to go arround and reconfigure for another type of app....

[lastdon]

http://www.youtube.com/watch?v=0qaDVaKQSkQ

:ok:

[Student513]

A Localiser/DME approach is an option should only the glideslope fail, using DME distances to determine what height you should be at (which you should be cross-checking anyway). Operators SOP's will no doubt detail the criteria for this though.

Out of interest, what is the usual height that you would be able to transition to this type of approach if the glideslope needle disappears (without having to carry out the missed approach and start again)?

[moggiee]

Out of interest, what is the usual height that you would be able to transition to this type of approach if the glideslope needle disappears (without having to carry out the missed approach and start again)?
Anytime above MDA as long as the RVR does not preclude you continuing. Remember, whilst an ILS may be permissible in 550m RVR, the LLZ/DME will require a greater RVR than you have and (depending upon the stage of the approach) that may require an immediate go around.

[Nicholas49]

Thanks for your answers guys.

I expect some of you have seen this already, but I found an interesting video on youtube about ILS failures. It's in two parts. Here are the links:

http://www.youtube.com/watch?v=GelRBhJ4gmI&mode=related&search=
http://www.youtube.com/watch?v=qTy0U3UVjGE&mode=related&search=

[Student513]

Great, thanks moggiee