Hi All,

I'm new to this forum and studying from abroad (Missus an Ozzie and she wants to go home!) so please excuse any stupid questions.

I am working through the Bob Tait IREX book dated June 2010 and I was curious about a question on page 3.13 regarding Thangool alternate requirement. The preceeding text states that if the box is shaded and you can be certain of obtaining the actual QHH you can knock 100ft of the alternate requirement (and the approach MDA if I understand correctly) one of these approved sources is ATC, ATIS or AWIS (NOT METAR). So I checked the ERSA and it states THANGOOL has AWIS. This would indicate I could knock off 100ft from the alternate minima. Although this 100ft alleviation does not effect the requirement for an alternate in his particular example I was curious about how you obtain the AWIS over the phone in flight? Surely you can only get it before you depart. There is only CTAF at THANGOOL so presumably the QNH cannot be passed by ATC and I dont think I would be on the phone during the approach phase obtaining the weather.

In effect your destination could be at the far reach of the range of the aircraft and several hundred miles away so what is the benefit of obtaining the AWIS prior to departure?

Am I missing something? Is it common to use a mobile phone in flight? I would be be very surprised and being a chopper pilot not exactly practical as I can barely hear anything anyhow.

Thanks for any help with this

Robbie

Hi All,

I may have just discovered the answer to my previous query!! It would seem some airfields/aerodromes have an AWIS broadcast on VHF. So in that case you would obviously recieve the actual QNH.

I did not realse there would be both an ATIS and AWIS. The only difference I can see from the AIP is that the ATIS is recorded from a certain time and broadcasts the airfield data as at the the time it was recorded. AWIS is real time and continually updated.

Have I got it?

Robbie

Sounds like you're onto it!

Thanks for the reply. Coming from 7 years of IFR flying in Europe there do seem to be a few oddities in that AIP!!

May be just me.

No worries. I'm a low hr (~700) heli pilot who did my IR exam to try and improve my employment prospects and highly doubt I'll be using the knowledge anytime soon. In an attempt to not forget the stuff I learned I check up in here to see if I can help others with anything so post away if you have any questions. Sounds like you'll be right though.

When it comes to subtracting 100 feet from the MDA or Alternate Minimum, the QNH must be from an 'approved source'. ATIS is considered to be an approved source because if the QNH changes significantly, a new ATIS is prepared. AWIS on the other hand, is broadcast on VHF at some aerodromes, but it is available only via phone at others. CASA's interpretation is that if you get the ATIS by VHF - that's OK. But you can't be sure before you depart that the mobile phone service will be available. So QNH from AWIS by mobile phone is not considered to be an approved source.

Hi Bob,

Thank you for the reply. Much appreciated. If you dont mind I have put in another thread.