Tower Frequency DOC

[Chuffer Chadley]

Good evening!

Yesterday at IOM, I overheard (while waiting for some SLF to arrive) an interesting conversation on IOM tower frequency. There was a barely readable (to us) transmission from a Clifton (CLF) callsign, to which the tower responded with:
"Clifton 10, how do you read?"
A further, unreadable transmission from the CLF aircraft. Then, again, TWR responded with:
"Clifton 10, how do you read?"
Nothing this time from the CLF. Then, a BEE aircraft helpfully responded with something along these lines:
"TWR this is BEExxx, CLF10 has acknowldged your transmission, he's trying to contact Kemble tower."
TWR: (rather grumpily) "Yes, I know. I'm just trying to get a point across......he should know what the DOC of a tower frequency is."

OK, so a couple of questions-

What's the DOC of a tower frequency? Does it vary from field to field? And where's it written down? I certainly don't remember it being mentioned in any of my training, but that doesn't mean it wasn't!

Also, is that the kind of thing you ATCers imagine that we know? My captain didn't either...

Cheerio!
CC

[BigBoeing]

our tower has a DOC of 20miles ish, though as you say, Im not aware its written down anywhere and I know from experience it far exceeds this range.

[Chilli Monster]

UK AIP GEN 3.4.3.2


2.2
Use of VHF R/T Channels


(a) Geographical separation between international services using the same or adjacent frequencies is determined so as to ensure as far as possible that aircraft at the limits of height and range to each service do not interfere with one another.

In the case of en-route sectors these limits correspond to that of the ATC sector concerned and those for international aerodrome services are appropriate a radius of 25 nm up to a height of 4000 ft (TWR) or 10000 ft (APP).

(b) Except in emergency, or unless otherwise instructed by the Air Traffic Services, pilots should observe these limits. Services other than international services are provided on frequencies which are shared between numerous ground stations and have to operate to a higher utilisation in order to satisfy the demand for frequencies. Pilots using these frequencies should assist in reducing interference by keeping communications to a minimum and by limiting the use of aircraft transmitters to the minimum height and distance from the aerodrome that are operationally necessary. In the case of TWR, AFIS and A/G facilities, communications on these frequencies should be restricted as far as possible to heights up to 1000 ft in the immediate vicinity of the aerodrome concerned and in any event within 10 nm and 3000 ft.

[Spitoon]

It's often in the AIP - although, interestingly, neither IOM or Kemble have included it. If ATC people want to make a point it would be a good starting point to publish the info. As far as I know, th only other place that it is specified is on the radio station approval/licence.

[aluminium persuader]

Used to work at what was then a v busy training field. Tfc along the lines of 4 or 5 in the circuit, 2 or 3 in the stack with another on the procedure & a bunch or arrs and deps. Single freq twr & app procedural , working my bum off & get interrupted by airline c/s calling airport on same or close freq some 150 miles south of us for the wx. He's at f330 or something & blocking my freq for blummin ages.:mad: :mad: :mad:
Didn't happen just once but on many occasions. A phone call to the big airline's chief pilot helped, but crikey! what if I'd had an emergency? Wouldn't have been able to do a thing!

It's not so much the tower DOC but how strong the a/c's tx's are from altitude. HUGE safety implications that pilots need to be aware of.

ap

[chevvron]

DOC's are slowly being added to AIP entries for all airfields. Normal DOC for a TWR freq is 25nm/4000ft, but this can vary.

[Chilli Monster]

If pilots learnt the limits quoted above and stuck to them there'd be no need for individual DOC's.

Once again the problem is pilot education, nothing else.

[vintage ATCO]

We get serious pee'ed off at Old Warden with CAT calling Connaught/Knock way outside the DOC for the weather and then passing the passenger load, fuel requirement and how many wheelchair lift offs they have!!! Grrrrrrr.

On occasions the CAT tell me to be quiet so they can copy the weather! S'funny, I always have something else to say at that point. :E

Seriously though, during the actual display we are suppose to have a quiet frequency. We are talking to Gatwick about the problem.

[Lon More]

`VintageATCOBack when we were younger remember Luton and Maastricht both used 120.2 as TWR Freq. Dependant on WX it was often possible to hear traffic in the other circuit +250 n.m. away

[vintage ATCO]

I remember that bloomin' HS125 out of Coventry almost daily that called Maastricht in our overhead!

[OCEAN WUN ZERO]

EGBE
Serious problems with APP and Radar DOC ,one vs Headcorn and one vs Paris
Due to lack of available freqs may take a long time to fix if it can be!:uhoh:
OWZ

[Chuffer Chadley]

Interesting stuff, thanks chaps.

I think that the DOC issue is something that various ATCOs (thank-you, Chilli) could make a case for pilots knowing. However, if it ain't made clear to us (eg on an approach plate etc), then it might well be something, in practical ops, that gets missed out.

Have a nice Sunday!
CC

[Lon More]

HS125 out of Coventry almost daily
Can't remember that one. Did get a lot of visits from JCBs from East Midlands

[Spitoon]

Ahhh, JCBs. and UB's King Airs.


I used to think it was really sad to hear the old codgers reminiscing about 'the old days'...............but now I are one! (Which reminds me of a cartoon that I think once hung on Vintage's office wall.

[chevvron]

DOC's are being added to each airfield's AIP entry; if Jeppesen or AERAD fail to notify them to users then it's not the fault of the individual airfields, it's the fault of the TAP publisher.

[Chilli Monster]

Chevvron - teach them the contents of the AIP section I quoted, during the Comms part of the PPL/CPL/ATPL, and airfields wouldn't have to publish them in the first place!

Come on - Which part of "Line of sight" and "Finite number of frequencies" is so difficult to understand? :ugh:

This should be required knowledge, which shouldn't need to be published on the plates as it's the same everywhere.