I watched the preview of the segment, the main problem I found with understanding the calls was the amount of static, ie; a problem with the plane (or more likely) their recording equipment. The accent was there and only a minor nuisance and the two calls they previewed were pretty good considering they were recorded at training airfields (were you would expect people to make mistakes).
The 'journalist' commented that thousands of Australians were at risk due to these poor calls.
I would say this is a beat up that just exhibits chronic racism.