Primarily for general aviation discussion, but other aviation topics are also welcome.
User avatar
By 2Donkeys
FLYER Club Member  FLYER Club Member
#1850173
Perhaps a question for ATCOs

Flying my aircraft in the US with either Foreflight or with certain Garmin Avionics, it is possible for me to receive my IFR clearance electronically before startup via PDC. Not all airports are equipped to provide a PDC but many can. (I can also pick up a digital ATIS, in many locations). It's great because it speeds the start up process, makes entering the cleared route into the avionics a little bit faster and generally gets you ahead of the game.

Back in the UK, I've never received a PDC, but I do recall rumours of clearances and even, such as, squawks being available via some third-party software tools like Autoroute, if you filed your IFR flight plan with them. Looking this morning, I can't find that functionality so I don't know if it has been withdrawn or whether I hallucinated it.

Is there equivalent PDC functionality in the UK other than via ACARS?
#1850178
@2Donkeys it was originally set up by ACARS but I notice in the Birmingham AIP entry they say this:

Data link Departure Clearance (DCL)
Pre-departure clearance by datalink is available at Birmingham for suitably equipped aircraft. Details of the DCL service may be obtained from ATC Operations on +44 (0)121-767 1235.

Might be worth giving them, or your favourite airport, a ring and finding out.
User avatar
By 2Donkeys
FLYER Club Member  FLYER Club Member
#1850182
Thanks @Marvin . I suspect that refers to CPDLC as a delivery mechanism - which is a little above my pay grade. The US system works (in addition to CPDLC) via text and email for correctly authenticated aircraft and accounts.
#1850188
I suspect you right. The ACARS solution had specific needs to authenticate the originator of the request so pdc not given to wrong aircraft.

Digital ATIS is a broadcast to ARINC and SITA servers.

I think you can get your slot allocations from IFPS servers via text with a validated account/Aircraft but not PDC.

Might be worth having a chat with Rocket Route or EuroFPL to see what they can offer.
2Donkeys liked this
User avatar
By 2Donkeys
FLYER Club Member  FLYER Club Member
#1850189
@Flyingfemme My experience in the US is that the PDC route you receive is often only vaguely related to the filed route, and EXACTLY the same as the one you would receive if you called Clearance Delivery. So much so that if your aircraft is registered for PDC, there is an expectation that you will take your clearance that way and will NOT call Clearance Delivery. What you ultimately fly may be different again for tactical reasons, but that doesn't detract from PDC.
johnm liked this
#1850194
@johnm perhaps more about the differences in operation between USA and Europe/UK.

PDC provides initial ground clearance information but nothing about the route, other than the departure SID and allocated slot time, target take off time etc, in the European model.

It’s a means of reducing workload for Ground Controller and an easy option to add to the modern electronic tower operations at the international airports, although places like Farnborough etc are also getting in on that game. There are no systems in place in the UK, or rest of Europe I believe, to issue a clearance to join airways from a non-airways connected airport like Blackbushe or Stapleford for example.

The USA quite often issue a quite lengthy departure brief including route information and takes up a lot of RT time. They also have a lot more smaller airfields without tower operations launching IFR flights so a digital text based solution is essential and removes need for telephone calls.
2Donkeys liked this
User avatar
By 2Donkeys
FLYER Club Member  FLYER Club Member
#1850196
Marvin wrote:The USA quite often issue a quite lengthy departure brief including route information and takes up a lot of RT time. They also have a lot more smaller airfields without tower operations launching IFR flights so a digital text based solution is essential and removes need for telephone calls.


All this is true - but it remains the case that full route-clearance PDC, even in the US, is only available from a defined set of airports. Blasting off IFR from an untowered airport still typically takes a radio or phone exchange with FSS.
Marvin, johnm liked this
#1850197
2Donkeys wrote:Back in the UK, I've never received a PDC, but I do recall rumours of clearances and even, such as, squawks being available via some third-party software tools like Autoroute, if you filed your IFR flight plan with them. Looking this morning, I can't find that functionality so I don't know if it has been withdrawn or whether I hallucinated it.


Autorouter used to send by email/text the ORCAM squawk allocated to the flight. IIRC, pilots departing uncontrolled airfields started setting the squawk on departure before contact with London/Scottish, which caused some problems for NATS (whether technical or procedural, I don't know). Thus Autorouter was asked not to send the information. Personally, I found that a pity, as at a controlled airport it was one less piece of information to deal with by RT at the hold.
2Donkeys liked this
#1850198
2Donkeys wrote: It's great because it speeds the start up process, makes entering the cleared route into the avionics a little bit faster and generally gets you ahead of the game.


BTW, have you ever received a clearance in Europe that was other than "flight planned route" after the SID? I can't remember any such occasion.
User avatar
By Iceman
FLYER Club Member  FLYER Club Member
#1850199
US IFR clearances are indeed historically legendary in their length, complexity and rate of speech, necessitating a short hand capability on the part of the pilot to have any chance of writing it down. PDC has made that so much easier, especially via apps such as ForeFlight. I think that the chances of getting a similar infrastructure for GA in Europe hovers around the zero mark.

Iceman 8)
Last edited by Iceman on Mon May 31, 2021 11:06 am, edited 1 time in total.
2Donkeys liked this
#1850200
@bookworm both technical and procedures issue. The allocated squawks would be picked up by the systems and activate the flight plan and then it would be assumed the flight was already under ATC control which it wasn’t.
User avatar
By 2Donkeys
FLYER Club Member  FLYER Club Member
#1850207
bookworm wrote:
BTW, have you ever received a clearance in Europe that was other than "flight planned route" after the SID? I can't remember any such occasion.


It has happened to me rarely, but it has happened. From Cambridge, an expected ADNAM departure (heading to Holland), that became a BKY departure, with a full re-route once in the air from London. I think the cause was industrial action by one of the usual suspects and aircraft were rerouted.

A second occasion was my shot at a cheeky routing to the west side of Scotland, than ended up being changed to be a tactical route in lower controlled airspace being dealt with for a while by the likes of East Midlands rather than London or Scottish
User avatar
By 2Donkeys
FLYER Club Member  FLYER Club Member
#1850208
Marvin wrote:@bookworm both technical and procedures issue. The allocated squawks would be picked up by the systems and activate the flight plan and then it would be assumed the flight was already under ATC control which it wasn’t.


My experience has been that London Control Group Supervisor has been happy to give me a squawk whilst on the ground when departing from an uncontrolled Cambridge airport at a weekend. Presumably, they can live with it when they know the departure is imminent.
AndyR liked this