Wow there are a lot of inaccuracies floating about on this thread. If you're going to criticise metadata, be sure to be technically accurate about what is being collected.
http://www.gizmodo.com.au/2015/10/everything-youve-been-told-about-data-retention-is-wrong/
Firstly with Internet, all they're logging is 'Person X had the IP address <something> between time A and time B'. That's it. No browsing history or tin foiled hat. ISP's have been doing this for decades for billing purposes. The legislation sets a min standard to make sure they all do it and retain records for 2 years.
For phone calls and SMS, the data retained is the same as it always has been since the 1920's - Person X called person Y for 5 minutes on this date. The legislation standardises a minimum requirement of what to store and sets a 2 year time before you can delete it.
The intent of metadata laws are for when the fuzz take down a kiddy fiddler computer and get a list of IP addresses on it. They can then quickly pair those with known accounts in Australia. It doesn't work the other way around; they can't surveil your porn fetishes and notify the convent about you.
CASA has always been able to access this information (via a warrant) so they will have no extra than normal. According to the original article, last year CASA had 11 warrants for this stuff.
So do I think it's a good idea granting CASA access to this? Nope. As this thread has demonstrated, there is already a large fracture and mistrust between the safety regulator and the industry it is regulating. I would not consider 11 warrant requests for metadata a difficult task for an organisation with ~ 850+ staff.
If the benefits of metadata access are just some internal efficiencies, I would suggest it would be in CASA's best interest to go through the courts via warrants for access to data. That way, they could move forwards to bridge the gap and try to adopt a relationship with the aviation industry that supports a positive risk free (generative is the buzz word) reporting/safety culture.
That said, if CASA deem timely access to metadata is an overwhelming benefit to aviation safety (for example preventing a crime?), then Skidmore should clearly communicate the reasons behind why they want access.
Edit: I'm actually not an expert on this so if I have any facts incorrect I'll be happy to change them (and my opinion!)