These tabs don't have hotkeys assigned:

StationPDAInventoryInventoryTab
StationPDAInventoryJettisonTab
PDAEquipmentManageGunnersTab

I'll also list

StationPDAMissionNotesTab

because while it has a hotkey assigned, the same hotkey is assigned to StationPDAMissionLogTab
and thus it won't work.

Finally, I already mentioned in another thread:

StationPDASensorNearbyTab

which has a working hotkey assigned, but it is not a letter that appears in the tab title and thus cannot be known by the user.