New Member Questionnaire


I just completed the New Member Questionnaire and one question stood out to me.

In my opinion I should read back the instruction given by ATC first before performing the assigned instruction. The readback is meant to be there to confirm that the instruction was understood.

I agree, readback, then, if ATC is happy with your readback, perform the action.

Ideally you would do both at the same time if you can be sure that you didn’t grossly misunderstand something, but if in doubt or if you physically can’t do both at the same time (if you don’t have some fancy setup with a hardware MCP or are already flying manually, doing both at the same time is usually pretty hard), then I agree with you and Lars: read back first, then start following the instructions.

Thanks so much for the replies. That’s what I was thinking.

There is a premise in Aviation in regards the priority of a pilots actions, so I guess it is testing that premise.

Aviate, Navigate, then Communicate.


However, if this premise is applied like that, it is severely misunderstood. It is not an instruction in which order to do things, it is an order of what to prioritize should an issue occur. It is meant as follows:

  • Aviate: is my aircraft still (stably) flying? If yes, then
  • Navigate: do I still know where I am and where I’m going? If yes, then
  • Communicate: am I still in contact with the correct ATS unit and do I need to speak to them?

In 99.9% of situations, this effectively means that after receiving an instruction, you read it back and then execute it, not the other way around. The only real justifications (strictly following the premise - there are of course some other, albeit more specific good reasons why you wouldn’t be able to reply immediately) to not reply promptly are if you are currently in the process of some upset recovery or have to solve a navigational issue (though in the latter, you might still want to prioritize talking to ATC as they may be able to help you solve that issue).

It is of course a bit of an issue on VATSIM where most people fly aircraft that are designed to be operated by a minimum of two people and the PF typically starting to follow the instructions as soon as they are given while the PM promptly reads them back. Likewise, controllers usually control much larger volumes of airspace (and especially during prime time also way more aircraft) than any real world controller ever would while they simultaneously don’t have the benefit of a planner/coordinator. This creates a situation where pilots tend to need more time to reply to and comply with their instructions and controllers tend to have less time to wait for readbacks.
If you look at single pilot operations in the real world, you can see that pilots generally start following instructions at the same time as they read them back, though as I mentioned above, depending on one’s setup this will usually not be possible in the virtual world, at least not easily. And considering that for most instructions it is not immensely crucial if you execute the instruction 5, 10, or 15 seconds after it was given as long as ATC doesn’t specifically tell you to do it immediately or similar (sure, if you are in terminal airspace on a downwind or base heading, you following instructions promptly is usually important regardless if you don’t want to lose your spot in the sequence - though in my experience failure to do so is usually caused by pilots falling behind the aircraft at which point the question should maybe rather be whether they are ready to fly to that airport at that time with that aircraft, but I digress), so all things considered, it normally makes much more sense, at least on VATSIM, to first read back, and then follow the instructions.

Thankyou anonymous for the explanation. I would be interested in a formal response from VATSIM. In my experience (not extensive or educated) the communication is a blocker on the network. It seems to be regular that a controller can wait a significant period to get a response from a pilot. In my eyes communication could also be the controller seeing the aircraft comply. I’m not saying that readback isn’t required, but in our crazy online world actions rectify situations. I have seen situations where the lack of immediate following of instructions causes virtual conflict because the time for the pilot to acknowledge and then execute took too long. Whilst I apparently have totally misunderstood the premise I still in my limited experience believe that I should act on instructions and then readback [if I can’t do both at same time].

I’ll ask my colleagues from Pilot Training to weigh in, but in my opinion, whoever “1627359” is said it well early on. “Ideally you would do both at the same time.” However, I do subscribe to the “Aviate, Navigate, Communicate” mantra. Given a situation where a pilot is task saturated and may not be able to “do and read back” at the exact same time, I would expect the “do” immediately followed by the read back as soon as possible. Sean, don’t sell your experience short – you are spot on – act on instructions and then readback [if I can’t do both at same time].

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I mean, I can only refer to what I learn(ed) in my own pilot training where it was explained explicitly as not a general order of operations, but an order of priorities to keep in mind, as I laid out above. I did a quick Google search on the phrase to see if I could find a more definitive answer on how it is meant and even though I didn’t, most articles seem to focus on the “don’t put your sole focus on troubleshooting some small issue but always make sure you are still actively flying the airplane, avoiding terrain/other traffic, talking to ATC/other aircraft where applicable, etc.”

From an ATC perspective, I can only tell you how annoying it is to have to wait for readbacks. Particularly in busy areas (and the problem only gets worse the “higher” you go because VATSIM’s topdown and training model has the unfortunate side effect that there are many aerodrome controllers, some approach controllers, and only few center controllers, whereas in the real world the distribution is usually the exact opposite way around), you regularly have a multitude of instructions lined up and having to wait ages for a readback means you have to wait giving these other instructions as well (I mean, you could give them regardless but that will cause a bunch of confusion on when pilots have to give their readback). That’s why many, if not most, controllers will usually call you up again if you didn’t respond for five or six seconds because at that point the assumption will be that you probably didn’t hear the instruction. This occasionally leads to the readback then being blocked out by the reiteration of that instruction, but much more often than not the pilot only gives the readback after being called up a second or third time. Were they actually not paying attention or just taking a lot of time to set their MCP before giving the readback? Who is to know; from an ATC perspective it really doesn’t matter. In this regard I also don’t really agree with this statement:

I certainly can’t speak for all VATSIM controller clients, let alone all real world controller software, but at least in EuroScope, the scope’s update rate is locked at five seconds (and while some ground, tower, and approach facilities are now getting advanced radar systems that can update roughly every second, an update rate of about five seconds is - to my knowledge - quite realistic for most facilities and you of course need to keep in mind that not all facilities actually have surveillance capabilities so in those cases ATC has absolutely zero way to see whether a pilot is complying with an instruction). This means that it can easily take 10-15 seconds before the scope starts indicating your turn/level change/ speed change/etc. and that doesn’t even tell me whether you correctly understood the instruction.

Sure, there are situations where you should start complying with an instruction before reading it back if you can’t do both at the same time, but unless it’s absolutely obvious to the pilot (or at least should be - this is also where my jab at pilot competency was aimed at because somehow people always end up surprising you with how unaware they are of even their own situation…), such as when you are on a tight base and get your intercept heading, any somewhat competent controller will append or prepend the respective instruction with a term like “immediately” or some further context like “due to traffic”. In all these situations, controllers will also know that it might take you longer to give a readback.
And if you not immediately following a normal instruction causes a conflict, then, frankly, the controller messed up big time (and even if they use “immediately” or similar in the instruction, these situations only occur if either ATC messed up or some pilot is not following their instructions, e.g. descending through the cleared level if you are just 1000ft below that cleared level). Luckily VATSIM is a virtual environment and we are flying/controlling pixels, not actual people, so if you actually end up hitting terrain or another aircraft, nobody will end up hurt (except maybe the pride of whoever messed up) - if you feel that it had a significant impact on your experience (which is of course a very subjective thing), then the best thing to do is probably to send feedback to the vACC so they can talk about the situation with the controller and give them additional training if necessary, because this is definitely not a situation that should ever occur (and if you are situationally aware enough to know that it is an immensely time-critical instruction, then I think it’s perfectly acceptable to comply first and read back later - same logic as before: ATC will know that this is the case).

And in regard to complying with instructions while reading them back, I wrote down some advice in this thread some time ago that should work regardless of one’s setup:

Something you can do here would be to have the mouse already on the heading knob in anticipation of the turn, start turning in the instructed direction while ATC is giving the instruction, then once ATC has finished talking, immediately read back, and only after that finish turning the heading knob (unless you can get it set up completely while ATC is still giving the instruction, of course) - that way you already start the turn and continue turning while reading back.

in real life other traffic may interrupt your communication and read back may be delayed…
if ATC requires immediate action you cannot wait until proper read back is completed…
thats why you should promptly do the assigned instruction