So, River lets us know that the tell-tale sound the TARDIS makes when it lands means, for some reason, that the brakes are on (‘The Time of Angels’ 5.4). It’s a funny line and considering the Doctor’s sometimes lack of awareness about his surroundings you can believe it’d be something he’d do.
However, the line gives me an irritating little itch in my brain for one reason: Romana. The Doctor traveled with Romana, a fellow Time Lord and a fresh from the Academy graduate who was given the highest marks, and she never once thought to mention this? Romana loved to show off the knowledge she had to her mentor. Why wouldn’t she speak up when they landed together for the first time and say something? “Yo, your brakes are on, idiot!”
This is Romana, who once in exasperation exclaimed “Not that one, Doctor” when he mucked up a take off. I know such thoughts are the absolute height of ‘pickiness’ and ‘over-enthusiastic nerding’ but here I stand.

I think it’s because Romana is a true brilliant Timelord. Let’s think it in a human way. Romana is a genius of the...
Yeah, at the Comic-Con panel Moffat said that it could have been that River was just messing with him. Maybe she doesn’t...
Pretty sure Moffat has even said that it was a joke. The Doctor has driven the TARDIS silently in ClassicWho before, and...
I believe River’s comment was meant as a joke. Just to tease him.