Dublin: 2 x RYR in contact during taxi. Both damaged.
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"ATC maintain a separation in the sky, (surely it would be possible to arrange the same on the ground)."
That's because normally you can't see the other guy, and you are travelling a high closing speeds. It's also in 4 dimensions. On the ground you are slow, and should normally only be concerned about threats in front of you that you can see and are using Mk.1 eyeball x 2. ATC has enough on their plate to play wet nurse on the ground. I don't know about all types, but you can see the wing tip of B738 from the pilot seat. OK, the threat might be behind you in a turn, but you have seen it and assessed it before the turn. When in doubt there is not doubt.
For ATC they do a wet nurse thingy at LGW & LHR and a fantastic job they do too: follow the greens at night. Fantastic, but then they are shuffling big lumps of aluminium in a maze of taxi-ways with many pilots who are very unfamiliar with the puzzle. Dublin is hardly in the Krypton Factor realm of challenges.
I do not wish to hand over more control than necessary to an outside agency. The captain has to maintain control and responsibility as a much as is sensibly possible. I see too many youngsters just follow an ATC instruction without assessing if that is what they really want to do. Head teacher gave an order and there'll be no dinner less you comply attitude. It's sad to see guys aim at a single Cu on a clear day just because ATC gives a radar vector. It's sad to see guys allowing ATC to suck them in hot & high without saying No. That's a whole new topic, so sorry for thread diversion.
That's because normally you can't see the other guy, and you are travelling a high closing speeds. It's also in 4 dimensions. On the ground you are slow, and should normally only be concerned about threats in front of you that you can see and are using Mk.1 eyeball x 2. ATC has enough on their plate to play wet nurse on the ground. I don't know about all types, but you can see the wing tip of B738 from the pilot seat. OK, the threat might be behind you in a turn, but you have seen it and assessed it before the turn. When in doubt there is not doubt.
For ATC they do a wet nurse thingy at LGW & LHR and a fantastic job they do too: follow the greens at night. Fantastic, but then they are shuffling big lumps of aluminium in a maze of taxi-ways with many pilots who are very unfamiliar with the puzzle. Dublin is hardly in the Krypton Factor realm of challenges.
I do not wish to hand over more control than necessary to an outside agency. The captain has to maintain control and responsibility as a much as is sensibly possible. I see too many youngsters just follow an ATC instruction without assessing if that is what they really want to do. Head teacher gave an order and there'll be no dinner less you comply attitude. It's sad to see guys aim at a single Cu on a clear day just because ATC gives a radar vector. It's sad to see guys allowing ATC to suck them in hot & high without saying No. That's a whole new topic, so sorry for thread diversion.
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AAIB report, BA/EI collision at LHR
Not related to this thread but interesting points raised re clearances.
http://www.aaib.gov.uk/cms_resources...pdf_032603.pdf
http://www.aaib.gov.uk/cms_resources...pdf_032603.pdf
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Maybe ATC cannot 'wet nurse' each aircraft 100% of the time, but an instruction such as 'Maintain your own 100m clearance from other aircraft' could get the spacing correct.
Whilst flying my Cessna, I avoid Hovering Helicopters like the plague, and keep at least 100m away, much the same as behind the CAT aircraft jet-blasts.
Whilst flying my Cessna, I avoid Hovering Helicopters like the plague, and keep at least 100m away, much the same as behind the CAT aircraft jet-blasts.
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Maintaining 100M clearance at LHR is just not going to be practical, especially when you have 15 aircraft queuing for the holding point! Also radar is just not accurate enough!
Exactly. Tower can literally be a mile away at times, even using the binoculars they haven't got a hope of seeing if 2 aircraft passing at awkward angles have sufficient clearance. Only those on the aircraft are close enough. Sensors in the stop bars detecting if someone's A**e is hanging out might help some of the problem, but with all the mixture of aircraft types and wingspans etc, it wouldn't make an enormous difference
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IMHO it is not up to ATC to instruct you to keep 10m/20m/100m from another a/c on the ground. It's your responsibility not to crunch another one. Coming onto stand, even self manoeuvring ones, the wing tip clearances are <10m. You follow the yellow line and use Mk.1 eyeball to ensure safe clearance: not just blindly follow yellow line. You assess what's in front of you and within the area you are going to place your a/c and act accordingly. Consider how close the wing tip gets to 'turn out stands' and the neighbouring a/c. Hopefully there is a wing marshaller, but not always. You manoeuvre starts with faith, then correct technique, then care. No ATC.
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April AAIB Bulletin RYR v RYR @ STN
The sole underlying cause appeared to be ATC unfortunately - the turn / stand geometry / angles and low 737 fuselage all meant that neither Flt Crew on taxiing aircraft or push crew on other could have reliably prevented it?
Exactly. Tower can literally be a mile away at times, even using the binoculars they haven't got a hope of seeing if 2 aircraft passing at awkward angles have sufficient clearance. Only those on the aircraft are close enough. Sensors in the stop bars detecting if someone's A**e is hanging out might help some of the problem, but with all the mixture of aircraft types and wingspans etc, it wouldn't make an enormous difference
I was considering the good, 'ole xpdr and thinking that maybe it could help ground control to better monitor the situation on tways and rways.
Instead of using it only up in the air, we could use it on the ground as well.
Get a dedicated code for ground ops so the ground controller knows exactly where you are at all times.
Once you're on the rway, switch to the "air" code.
Pretty much everything is already in place, we just need to use it a bit differently.
Aircraft are already squawking on the ground in DUB while taxiing. Area controllers can see the callsign, A/C type and SID on a screen linked to the ground radar, it's used to help them plan how to fit the next departure/departures in with whatever is already airborne. It is nowhere near accurate enough to ensure wing tip clearance.
