Maybe something in there is picking up the guard frequency. People make weird noises on that frequency all the time, including animal noises and screaming.
That wouldn’t go to the Public Announcement signal though.
Not on purpose, but there are YouTube videos of pilots accidentally doing in flight announcements on guard. Maybe there's some plane error that is sometimes causing the error the other way around.
I know Unites Airlines used to make its pilot’s atc communications available on “channel 11”, but I think that all stopped post 9/11.
I’ve heard it long after 9/11, but not in several years now.
I was on a 777 SFO-ORD a few months ago that still had Channel 9 available
I loved that so much. And it was enabled well after 9/11.
Pretty sure it was channel 9. I used to listen to that all the time.
Is the guard freq available (to receive from) at flight altitude? At least one of the reports supposedly involved the entire flight time.