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'Disregard' meaning & uses?

PostPosted: Tue Jan 24, 2017 6:07 am
by Althar93
Hello all,

I had a somewhat confused moment yesterday when flying off from Bakersfield to San Luis Obispo. This will probably seem trivial and obvious to some or perhaps funny to others but I thought I would share.

I was holding short of RWY 30R & ready for departure, got given my clearance for takeoff by ATC, then shortly after ATC issued a new message : 'FBTPC, Bakersfield Tower... disregard', which led me to think my takeoff clearance had been cancelled, so naturally I applied the brakes & kept clear of the runway.

A few seconds later, it became quite clear that ATC was just directing an approaching traffic to use the adjacent runway instead - ensued was me still holding short 'just in case' before calling back a few minutes later to ask if it was really ok for me to depart. @10:30, listen for 'FBTPC'.

Was I right to be confused, cautious?

Is there an official / approved usage of the term 'disregard' for communications? What portion of a message does the disregard actually 'disregard' : the previous transmission, or the current transmission? Similarly & from what I understand, a pilot using the word 'take off' outside of the clearance for takeoff read-back is highly discouraged. Is there a similar rule for ATC to cancel takeoff clearances?

Re: 'Disregard' meaning & uses?

PostPosted: Tue Jan 24, 2017 6:24 am
by Kyle.Sanders
"Disregard" is not covered in the P/CG but it will usually be used when a controller or pilot initiates a call but then decides not to finish that transmition. It might also be used as an advisory to the receiving party to disregard the last bit of information.

Now... for "official" talk:
The 7110.65 has this to say about cancelling a takeoff clearance. (ATC to pilot)
Cancel a previously issued clearance for takeoff and inform the pilot of the reason if circumstances require. Once an aircraft has started takeoff roll, cancel the takeoff clearance only for the purpose of safety.
In no case should a takeoff clearance be canceled after an aircraft has started its takeoff roll solely for the purpose of meeting traffic management requirements/EDCT.

Re: 'Disregard' meaning & uses?

PostPosted: Tue Jan 24, 2017 6:35 am
by zerofay32
In the context of the example 'FBTPC, Bakersfield Tower... disregard' the controller is disregarding the the current message. I'm guessing that FBTPC is your tail number? If it is not, then the call wasn't even for you to disregard.

In any case, if there is confusion always feel free to question the controller. A simple "I'm I still cleared for takeoff?" would have resolved it in a few seconds.
(EDIT: Ninja'd by Kyle who had the actual phase that ATC would use for a canceled takeoff.)

As for using "takeoff" in calls other than a clearance read back, there is no hard and fast regulation in the US. It is a recommended procedure for sure though.

Re: 'Disregard' meaning & uses?

PostPosted: Tue Jan 24, 2017 8:38 am
by Keith Smith
A controller would not use "disregard" call to cancel a takeoff clearance. So, now that you're aware that the phraseology is "cancel takeoff clearance" that should remove any doubt.

Re: 'Disregard' meaning & uses?

PostPosted: Tue Jan 24, 2017 11:59 am
by jx_

You were still cleared for takeoff. The controller was considering issuing a new instruction then changed her mind. 'Disregard' is a way to tell the pilot "ignore the fact that I just said your callsign and/or gave you an instruction." The only time I would apply disregard to any previous instruction is if the controller specifically says "Disregard last transmission/instruction," however this would be inappropriate for any instructions pertaining to a runway such as takeoff clearance/hold short/landing clearance etc... Those all require verbatim instructions and readback.

If you hear a controller say your callsign then say disregard, continue with your last clearance and no need to respond.

Re: 'Disregard' meaning & uses?

PostPosted: Wed Jan 25, 2017 3:36 pm
by Althar93
Sorry not replying any sooner - thanks a lot for your answers guys this all makes sense!