2010: The Year We Make Contact - Maybe Dave Forgot the Overrride
Near the end of the movie Star-child Dave enters the Discovery and tells HAL to re-align the antenna towards Earth. HAL balks at this, so Dave says to execute "Priority Override Alpha".
Now where, I ask you, was this override nine years before, when Dave wanted HAL to open the pod bay doors?
Bowman did not know about the override when he was "alive". Only after he became the star child, he was "allowed" information he had no prior knowledge of. Remember that Bowman was kept in the dark by NASA about a lot of things. Its reasonable to assume that he was uninformed of certain ship functions.
As an aside, it's worth noting that Dave refers to the "AE-35 antenna" in his directions to HAL. This was included, I expect, to add continuity with 2001, where the term "AE-35" is used in reference to the antenna. The problem with his statement is that the AE-35 in 2001 is the part of the antenna control system that HAL predicts will fail, causing Frank to EVA to retrieve it, and to discover that the failure warning was in error. The antenna isn't the AE-35, the module is. This interpretation supported by the fact that Frank and Dave refer to getting another AE-35 out of ship stores and leaving analysis of the original to others after they return to Earth. Ultimately it leads to Frank's murder. I suppose I'd be remiss if I didn't also note that when HAL accepts no corporeal Dave's order, the scene cuts to an exterior shot showing the main antenna swing up and over to align with the long axis of Discovery and in the ships direction of travel. HAL then reports that he's locked on to Alpha Terra One and commences transmission. Recall that HAL's protestation to Dave's command is that if he moves the antenna into that position he will be unable to continue to relay his observations to the Russian ship ow hurriedly making its escape. The problem with the scenario is that Discovery has just been used as a first stage rocket to begin the escape. Therefore, the Russian ship is traveling in the same direction as Discovery: forward along Discovery's long axis. To relay the signals using the antenna, it would have had to already be oriented in the direction Dave wished. One could posit that somehow the main antenna was necessary to make the observations, thus explaining its orientation towards Jupiter below, but in no other part of either 2001 or 2010 is any assertion made to support the assertion that the antenna has that function. Plus, if HAL needs the antenna pointed towards the Russian ship to relay observations, as he claims, he couldn't have been using it for observations.