Hi Bob

I am having trouble finding the reference in the AIP for the addition of 0.9km to published visibility minimum for NPA when HIAL is installed but not serviceable. (page 5.63 of your book - I can find the reference in my old AIP but not my updated one)

Thanks
Trent

Gidday Trent

The reason why you can't find the reference is because it isn't there anymore. It has been dropped from the AIP. Strangely, there is an NPRM out from CASA where it is still mentioned. I am wondering if it has been deleted by error when they rewrote the section on reduced visibility operations [most of which applies to the heavy jets rather than GA]. I wouldn't be surprised to see it appear again in some future AIP amendment.

In the mean time, nobody could mark you wrong if you said it is not a requirement under the current AIP.

Bob

Thanks Bob

Further to the discussion concerning adding 900m to the visibility required for a runway aligned NPA when HIAL is not available. Here is an extract from a reply received from Air Services. Should clear it up.

Below is a reply from CASA - Jan Goosen, who is the architect for the change in regards to the deleted para 5.4 -

The AIP reference has existed in error in the AIP for some time. It originated from a time when non-precision approach (NPA) procedures were designed with a visibility 'allowance' if the runway was equipped with an approach lighting system (ALS). In other words, the chart visibility minimum is derived by calculation which included subtracting a distance value equivalent to the length of the ALS (normally 900m).

The AIP reference covered occasions where an NPA was conducted to an runway for which the installed ALS is unserviceable. In such situations, the designed reduced visibility inappropriate and the 900m would have to be added to the chart visibility minimum.

With the introduction of Manual of Standards (MOS) Part 173 (Instrument Flight Procedure Design), the procedure for providing an ALS 'allowance' for NPAs was discontinued. See paragraphs 9.1.1.3 and 9.1.1.4 of MOS Part 173 located here: www.comlaw.gov.au/Details/F2007B01090 . Accordingly, NPAs for runways equipped with ALS are not designed an allowance for the ALS length.

Therefore, for NPAs to runways for which the installed ALS is unserviceable, there is no need to add (increase) the visibility minimum by 900m because 900m was never subtracted in the first place.

We have informed Jeppesen of the error in their DAPs in reference to HIAL.

Hope this helped in clarifying your query.

Kind regards,
Sien

Sien Loh
Publications Unit | AIS
www.airservicesaustralia.com

Hi all

For anyone now reading this thread, be aware that the requirement to increase the visibility minima by 900M for a NPA seems to have been reinstated in the 8 March 2012 AIP amendment (ENR 1.5 Para 4.7.1) but only for a LOC approach.

Thanks Zabar

I'll make the necessary changes to the IREX book. What a pain in the butt! I seem to spend a lot of my time trying to keep up with CASA. I always suspected that the original removal of that requirement was unintentional. Looks like I was right.

Cheers mate

Bob

You're welcome. Between your book (July 2011 version) and this forum I feel it is preparing me pretty well. I feel your posterior pain - I teach CPL Heli theory and am also forever trying to keep up with CASA's changes. Not to mention teaching Heli specific rules only to find that they rarely seem to be examined.

Yes, I often wonder why they insist on having a separate exam for Heli Air Law.

Why not examine the helicopter specific stuff [there's not much of it], as part of their oral exam prior to the flight test.