Frequencies-SMC vs SMC(V)

[helopat]

Little background first...

At a military airfield where 'this friend of mine' works there is a surface movements frequency (SMC) and a separate surface movements frequency for vehicles (SMC(V)). The policy of the Air Traffikers at this military airfield (or so my friend tells me) is to operate with SMC and SMC(V) in retransmit mode (ie. pilots hear vehicles and vice versa, which 'my friend' finds very distracting as a pilot).

At the risk of bringing down the wrath of ATCers, my question is: should the two frequencies be retransmitted (ie. a pilot taxiing hears all the vehicle movement requests around the field and vice versa) or should the two frequencies be operated independently. As a pilot I (er, I mean, my friend)(perhaps selfishly) feels that the danger of the SMC(V) radio chatter being retransmitted on the SMC frequency is potentially dangerous for aircrew, especially in a training environment. The Air Traffikers contend that this setup to helps everyone maintain better Situational Awareness and are only willing to deselect retrans in case of aircraft emergencies.

Anyone want to weigh in on this relatively minor issue?

Thanks.

[Standard Noise]

Don't suppose the cross coupling could be set up so the vehicles can hear the aircraft, but not the other way round? Works for me.

[VATCO]

SMC

Must agree at most airfields I have worked at a cross coupling is used so that vehicles can hear aircraft but unless full cross coupling is selected then aircraft should not hear the vehicles. This system works well and keeps the vehicles aware of aircraft movements without distracting the pilots.

[vintage ATCO]

Hmmmm, an interloper . . . . .

We operate with the GMC frequencies part cross-coupled, vehicles hear acft but not vice-versa, but the AIR frequencies fully cross-coupled so everyone hears everything that's going on around the runway.

The trouble with the former is that if a tug is passing some towing request he can get stepped on by an acft. You deal with the acft and then have to ask the tug to say again. This just adds to the RT time and work load. Some of us would like GMC fully cross-coupled.

[Il Duce]

Have to agree with that point about having to repeat r/t. Last tower I worked in had those freqs operating independently. The Ground Controller dealt with the aircraft and the Assistant dealt with the vehicles however, both monitored the other's frequency to maintain situational awareness. Pilots trusted ATC and vehicle operators to be switched on and adhere to the rules to ensure safety.

[HEATHROW DIRECTOR]

At Heathrow (and other NATS airfields) the UHF frequencies used by tugs and other vehicles which were cross-coupled to the VHF Air and GMC frequencies were dedicated to those tasks alone. By this I mean that ATC and aircraft would only hear calls from vehicles which were of concern to them - runway crossings, towing aircraft, etc. To talk to their bases vehicles switched to another UHF channel which wasn't coupled to any ATC Frequency. ATC had the ability to uncouple the link if the UHF frequency became jammed but I never recall using it. It all worked an absolute treat...

With great respect to my ATCA colleagues I don't like the system outlined by Il Duce. The operation of the manouvring area at an airfield with a licenced ATC Unit should be in the hands of an ATCO. If an incident occurred and the ATCA was at fault, who would bear the responsibility? Probably the ATCO.

[Il Duce]

HD, agree that ATCO is ultimately responsible for preventing collisions between flying type machines and other moving stuff on the deck. I can see the problem arising where some aircrew are trying to concentrate on checks and being distracted by r/t from vehicle movements which are unrelated to their taxi route etc.

[vintage ATCO]

Originally Posted by Il Duce

I can see the problem arising where some aircrew are trying to concentrate on checks and being distracted by r/t from vehicle movements which are unrelated to their taxi route etc.

What's the difference then between hearing r/t from aircraft movements which are unrelated to their taxi route, etc. This is a non-problem.

[Il Duce]

Sorry, perhaps what I was hinting at was the reduction of unnecessary r/t.