IFR Clearance on Taxi

[Gannet167]

I've flown in to a few airports where you request startup, get a taxi clearance, and while doing your checks and trundling down the taxiway trying not to cross an active runway etc. - only then are you given your IFR clearance. The clearance may include some changes, which you may or may not be able to accept and may require flipping through some charts, looking at climb gradients, equipment requirements etc. It just seems to me that you really couldn't pick much worse of a time period to provide a clearance - for safety and for accuracy. Why would an airport insist on doing things this way? Why would ATC not be able or not want to provide IFR clearance before engine start?

[photofly]

A clearance involves the ARTCC reserving a block of airspace exclusively for you, at least until you're airborne and positively identified on radar at which point radar separation can be applied. In order to accomodate as many aircraft as possible ATC wants to minimise the amount of time your departure blocks out the airport, so the closer to your actual time of take-off that Centre hands your clearance to the tower, the better for them to provide service to everyone else.

That would be my guess.

[parrot_head]

Why would ATC not be able or not want to provide IFR clearance before engine start?

If you are talking to a FSS or tower, they may or may not have your IFR clearance readily available. With a FSS, in most cases, they have to phone the IFR control centre and request your clearance from the IFR controller. They will, in turn, relay this clearance to you.

With the towers, I believe most (but not all) have your IFR clearance readily available in the form of electronic strips and can issue your IFR clearance immediately with no need to call the centre. I believe some of the busier FSS sites are also starting to utilize this technology to simplify the issuance of IFR clearances.

As for protecting airspace, it all depends on the classification of the surrounding airspace and the level of control service that the tower can provide.

[HeadingAltitudeSpeed]

Why would ATC not be able or not want to provide IFR clearance before engine start?

If you are talking to a FSS or tower, they may or may not have your IFR clearance readily available. With a FSS, in most cases, they have to phone the IFR control centre and request your clearance from the IFR controller. They will, in turn, relay this clearance to you.

With the towers, I believe most (but not all) have your IFR clearance readily available in the form of electronic strips and can issue your IFR clearance immediately with no need to call the centre. I believe some of the busier FSS sites are also starting to utilize this technology to simplify the issuance of IFR clearances.

As for protecting airspace, it all depends on the classification of the surrounding airspace and the level of control service that the tower can provide.

Actually most towers don't have the ability to issue you an IFR clearance without first receiving it from the IFR unit responsible. The ones that can have arrangements with some standard (often including a SID) portions. While a tower (staffed by a controller) can issue a clearance, a FSS (not a controller) can only relay one. As a result until you are on your way and moving the lines of communication are not established.

Airspace to be protected all depends on the tolls available to the IFR controller. The tower has nothing to do with your IFR clearance. Towers control the runways and VFR traffic (again a few exceptions). IFR clearances are the responsibility of the IFR unit (Terminal or Enroute). Towers allow IFR controllers to designate some responsibilities but ultimately your IFR clearance is their bag.

If you are being issued your clearance while taxiing and are unable to understand or confirm it then just advise the issuing agency that you are unable at that time and request it when you are at the threshold, checks and run-up completed.

[ahramin]

I've flown in to a few airports where you request startup, get a taxi clearance, and while doing your checks and trundling down the taxiway trying not to cross an active runway etc. - only then are you given your IFR clearance. The clearance may include some changes, which you may or may not be able to accept and may require flipping through some charts, looking at climb gradients, equipment requirements etc. It just seems to me that you really couldn't pick much worse of a time period to provide a clearance - for safety and for accuracy. Why would an airport insist on doing things this way? Why would ATC not be able or not want to provide IFR clearance before engine start?

Gannet, it's very simple. When you request the clearance from FSS or ATC, they pass that request on. When the clearance comes back, they let you know. You don't HAVE to take the clearance at that exact moment. Single pilot ops, I would never take an IFR clearance while taxiing. Your options are:

1. Request the clearance and hold where you are until it comes back, take it, then taxi, or

2. Request the clearance, taxi, and when the clearance comes back stop somewhere, take it, then continue the taxi.

[Gannet167]

It's not that simple, or that convenient. I call delivery and request IFR to wherever. They say "IFR on request advise ready to taxi" so I advise ready. They will say "clearance on the taxi" you cannot get clearance before taxiing at this airport, you only get it while rolling to the runway. Then they give it to me and we flip through the charts to find the convoluted SID that we weren't expecting, check climb gradients, see if we can do it with the required equipment for that SID, re-load the FMS, check the FMS' routing against the SID routing, complete a taxi check and try to not have a runway incursion. It ties up valuable time with the engines running. I just don't see why they can only issue it if you're moving. Why they can't issue it while sitting still and preparing for departure is confusing.

[ahramin]

Care to share what airport? I've not run across an airport busy enough to need multiple SIDs that wouldn't give you the clearance before engine start so it's difficult to comment.

Have you contacted the ACC Manager?

[HeadingAltitudeSpeed]

I would be interested to know which airport this is. It sounds like a very strange requirement. Perhaps there is a reason but I can't pull one out of my ah head...

[linecrew]

Don't they usually say something like "I have your clearance, are you ready to copy"? Just tell them to standby until your ready to deal with copying it down.

[thatdaveguy]

Don't they usually say something like "I have your clearance, are you ready to copy"? Just tell them to standby until your ready to deal with copying it down.

Exactly. Generally we (FSS) have no issue if you call ready to taxi but you want to wait in the run up bay for your clearance. As long as you are ready to go in a short time frame after receiving the clearance, that's fine. Many pilots await the clearance the hold short line and don't start the back track until they are done reading back. That's fine.

[floatyghosthat]

Keep in mind as well that FSS regulations dictate that a clearance must be relayed to the aircraft within 3 minutes of receiving it from the ACC. If we say "clearance when you're ready" and you tell us to standby, we only have 3 minutes before we have to go back to Centre and either cancel or revalidate the clearance. It's not a big deal for me (I can't speak for all FSS), but if there's other traffic in the area, it might mean a delay for you.

Also, in some sites which are bordering other control zones or FIRs, the controller needs to co-ordinate with the other Centre before being able to issue a clearance. Therefore, some clearances are transmitted as such; Aircraft -> FSS-> Local ACC -> Adjoining ACC -> Local ACC -> FSS -> Aircraft. As you can imagine, there are lots of opportunities for delays and complications. In my expereince, things usually move quite quickly and smoothly, but keep in mind that that's not always the case.

Another point of consideration is that (in our FIR anyway) expected departure times are passed to the ACC when the clearance is received. If the aircraft does not depart within 3 minutes of the expected departure time, then the FSS has to go back to the ACC to update it. Sometimes this may result in a cancellation of the clearance due to other traffic, as once a clearance is issued, airspace is considered "closed" for all other IFR aircraft. Cancelling of a clearance doesn't happen often, but if it's 5 minutes passed your expected departure time and you're still running on the ramp while there's traffic holding on the approach, you will most likely lose your slot. The easiest way to stop this from happening is for FSS to ask for an expected departure time from the pilot or to wait until the pilot is ready to go (ie. on the taxi) before getting a clearance.

There's not really much that you as a pilot can do to make things run more smoothly. Usually the vast majority of these delays are caused by poor or non-existant radar coverage.

[DHC-1 Jockey]

Some of you make mention of FSS needing to call the IFR controller to get the clearance which takes time. At YSB and YYB though, we can get a pre-taxi (or copy it down while taxiing) clearance, and they can give it right away without calling centre, and it's always the same standard clearance. It goes like "C-FABC is cleared to XXXX airport, centre stored route, depart runway 22 on the Sudbury 2 departure, squawk 1234, do not depart until clearance validation received." We then read it back and while we're taxiing or waiting in position, we get from FSS "Clearance validation received" and we're good to go. No need to get the full spiel from centre besides the validation. Other airports like YXL and YAM (when operating as an FSS) still need to call centre to get a full clearance. This new pre-taxi clearance really speeds things up.

[kevenv]

Some of you make mention of FSS needing to call the IFR controller to get the clearance which takes time. At YSB and YYB though, we can get a pre-taxi (or copy it down while taxiing) clearance, and they can give it right away without calling centre, and it's always the same standard clearance. It goes like "C-FABC is cleared to XXXX airport, centre stored route, depart runway 22 on the Sudbury 2 departure, squawk 1234, do not depart until clearance validation received." We then read it back and while we're taxiing or waiting in position, we get from FSS "Clearance validation received" and we're good to go. No need to get the full spiel from centre besides the validation. Other airports like YXL and YAM (when operating as an FSS) still need to call centre to get a full clearance. This new pre-taxi clearance really speeds things up.

May be new in your area but we have had it for a number of years now. Plus only approved airline operators can use it.

[DHC-1 Jockey]

Yeah it's new here in the past year or so. And I didn't know it was for airline use only. Good to know.

[Jonathan]

Having worked at YSB FSS I can definitely say that pre taxi clearances are much more efficient and reduce communications between FSS and ATC a lot. Not only for the pilots it's better because they have the possibility the copy the clearance while engines are not running, but also for us it's easier to simply call ATC and say "BLS420 runway 22 Sudbury 2" and get validation than having to call ATC to get the clearance, do the readback, then the relay, then another readback in the middle of a traffic situation.

This procedure requires an arrangement between the FSS and the ACC, that is why some FSS use it, others not.