Whenever I'm at a class D, I'm always confused as to why the ATIS says "read back all runway assignments and hold short instructions." Isn't that just a given? It seems redundant and it takes up valuable time in the ATIS broadcast. If I tune in half way through the reading, I don't want to have to sit there for 5 minutes just to hear the whole thing.
Due to the ongoing runway incursion epidemic, US ATC must hear every aircraft read back certain instructions, including callsign. If you don’t read them back correctly, they’re required to repeat the instruction until you do. No matter how many times it takes.
When this rule was first adopted (or at least enforced), a shocking number of pilots couldn’t give proper readbacks. This caused a lot of frequency congestion and other issues, such as making an aircraft on final go around or holding departures just because someone taxiing toward that runway wouldn’t properly confirm they’d hold short of it.
Things have gotten somewhat better as pilots have learned, but it is still common enough of an issue in practice that they won’t take the reminder off the ATIS. And since some other countries either don’t have or don’t enforce this rule, it may never go away.
Aviation can be very unforgiving at times. One of the ways to deal with that are so-called idiot proof systems. Checklists are a good example. The reason we use them is not to help us remember what to do, but to make it impossible for us to forget what to do, as long as we can get ourselves to remember to use the checklists.
"Read back all instructions" is another example of the same idea. Seemingly overdoing it, it protects us from the part-time idiot that lures inside each and every human, waiting for that one moment to make any one of us make that one incredibly stupid mistake.
Failure to readback runway assignments and hold short instructions is still a common occurrence. Enough so that the brief moments taken by including the reminder on ATIS are nothing, when compared to the time taken to query pilots, and make second transmissions, to elicit the necessary information.
It only takes one error (did he say hold short, the left, or right runway?) or one missed clearance, or one missed hold short instruction, to lead to a runway incursion or mishap.
The announcement is made at so many locations on ATIS because it's a widespread, ongoing problem, and has been, for many years.
This procedural requirement is not established by Federal Regulation (FAR) but is specified in the Aeronautical Information Manual (AIM). After getting their pilot's license a surprising number of pilots forget the AIM exists, and eventually forget that the procedural requirement (and hundreds like it) exists. Therefore the reminder in the ATIS.
AIM Chapter 4 - Air Traffic Control, Section 3 - Airport Operations, Paragraph 18 - Taxiing…
(a) General… (9). When taxi instructions are received from the controller, pilots should always read back: (a). The runway assignment. (b). Any clearance to enter a specific runway. (c). Any instruction to hold short of a specific runway or line up and wait.
(10). Controllers are required to request a readback of runway hold short assignment when it is not received from the pilot/vehicle.
Since a landing clearance may include a Land And Hold Short Operation (LAHSO) that is similar to 9(c) above, further read-back guidance is provided…
AIM Chapter 4 - Air Traffic Control, Section 3 - Airport Operations, Paragraph 11 - Pilot Responsibilities When Conducting Land and Hold Short Operations (LAHSO)…
(b)… (7). Controllers need a full read back of all LAHSO clearances. Pilots should read back their LAHSO clearance and include the words, “HOLD SHORT OF (RUNWAY/TAXIWAY/OR POINT)” in their acknowledgment of all LAHSO clearances. In order to reduce frequency congestion, pilots are encouraged to read back the LAHSO clearance without prompting. Don't make the controller have to ask for a read back!