Hi All,

I am working through the Bob Tait and I have also just completed and passed (phew!!) a practice IREX a mate of mine gave me.

In Bobs book he states that one could convert a ILS approach into a LLZ approach if you experienced an atltimeter discrepency - see page 5.62.I am sure Bob is correct but I cannot see where he has this refernce from.

The AIP states that you must commence a MAPT if you believe your nav aids are 'suspect'. This makes sense but if Bob is correct what is an acceptable error in converting an ILS to LLZ approach with regard the altimeter, 100ft, 200ft?? The altimeters have been checked prior to depature with an accpetable error of between 60ft and 75ft. Now we can accept 100ft on approach.

Any thoughts?

Lastly I have read on the BladeSlapper site and in Bobs book that I need to brush up on my met knowledge. Can anybody recommend any refernce material?

If you check out AIP ENR 1.5 para 7.3.1, it says that the altimeter check on the ILS approach must me made and if it reveals an 'unexplained discrepency' , the ILS approach must be discontinued. That doesn't mean that you must do a missed approach - it means that you can not continue with the ILS approach to the ILS DA. There is no reason why you cannot continue with a LOC approach since you are well within the limits required to continue a LOC to the LOC MDA.

As far as Met revision is concerned, I have recommended that because some students may not be up to speed in interpreting the TAFs. If you feel you are current with all of the meteorological messages, you probably don't need to do that.

Ah ... I see Bob has beat me to it ....
Yes .... What is a discrepancy. ... Or even what is unexpected ... Given the absolute pedantics CASA demonstrates in their examination system (questions), you'd think there would be better clarity.
I recently did the IREX exam and in preparation had many queries like this .....you might like to have a look at some of these queries.
good luck ...
David