thunderstorms

[bird on the wire]

At STN yesterday teatime when the TS and CBs were making their presence felt, departures in our direction were postponed due weather. As a pilot, I was wondering what are the problems for you as controllers in these of conditions and how do these create the delays?

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they bought their tickets - they knew what they were getting into

[Dytter]

Can only speak for TC, but I guess it's at the lower levels that you are most affected, right? The sector capacities are calculated assuming that aircraft follow predetermined routes. As soon as a/c deviate from these routes the workload for a given sector rises enormously due to increased coordination and the random nature of the wx avoidance. No 2 a/c ever seem to want to go in the same direction to avoid, and after you've worked your ******'s off to accomodate everyone, a puddle jumper flys straight through the middle of all the wx with no trouble at all! Our ability to maintain a safe operation is seriously compromised by wx avoidance, and we therefore impose restrictions to keep the traffic to a manageably safe level. Remember that we have NO wx info on the radar screens. When we insist that you stay on a given heading, it isn't out of bloody mindedness, it's for your own safety. Next time we have wx like this, why not ring up and send someone in from your company to see just what we have to deal with? Also, please don't turn and tell us afterwards - ask first. One a/c I worked a while ago turned right at BPK straight into the LAM stack with 8 a/c holding fron FL80 to Fl180.
Keep a good lookout!

[chiglet]

At EGCC, we "try" to be openminded. IF you are lined up and ask for WX avoidence we [the air/APC/area] controllers WILL try and give NSD's (None Standard Deps) due WX. If not "your" choice, then a reasonable compromise.

[Flanker]

Interesting post Dytter.

First let me say that the controllers in the London area are excellent,in very busy airspace.

You said it yourself though, you cannot see any weather on your radar, are you given any guidance on the severity of the weather?
Much of the weather avoidance we ask for is as much for comfort as safety I admit,but there are times when keeping a heading is just not an option.

Heavy CB's are bad news but I can see its difficult for you to know how serious the weather actually is.

I have seen weather I would never fly through no matter what you told me to do, and believe me if you were a passenger you'd be the last to disagree.The other traffic might whack you but some CB's definitely will!(Not often in the UK but they do appear)
Don't have a heart attack but TCAS would help if this happened.

Also getting a word in edgeways is quite often a problem in the London area even when the weathers good.

When I flew puddle jumpers I flew through some things I never would now.Its called experience and having weather radar!

[fweeeeep]

Hello all,

Both sides here face major dilemmas when it comes to bad wx operations, the pilot will not/ can not take an aircraft through a "hard" cell. The ATC will not put you on a collision course with another aircraft.

I have found in the past that pilots often make a very late request for wx avoidance, and thus reduce ATC options significantly.

Perhaps the solution is two-fold, as a pilot asks with as much notice as possible for a preferred (and alternate) heading. As ATC's we should put pressure on management to pay for software upgrades that will generate synthetic processed information regarding wx "hard" cells, so that we too can see the nasty stuff and plan accordingly.

Just some thoughts....

[Over+Out]

I was working yesterday and at one time I was very busy, yet not one of the aircraft I was controlling was in my airspace. We would very much like to have WX radar, we have MIST, but this is not very good for our purpose. I hope The Airline Group will buy us a WX radar to give us a clue of were it all is!

Also we are very short of ATCO's and people were working over 1 1/2 hrs without a break and this is very tiring. Unfortunately shortage of staff will be a long term problem. Therefore to help us out flow rates are applied and departures may be slowed or stopped.

[vertigo]

As a result of weather avoiding yesterday, massive flow restrictions were in place until late evening. departures were stopped intermittently and as a result, ground congestion meant increased spacing. at the end of the evening 55 aircraft an hour were arriving at the heathrow stacks and i'm sure many flights were cancelled. This is the impact your requests can have. If it is for 'comfort' think twice. Is it fair to have 100 of your customers more comfortable at the expense of 1000's being late and some not even arriving at there destination ?

If you deviate without a clearance, yes, TCAS will help. But there are still aircraft without transponders. Remember the Britania and the USAF fighter ?

[HEATHROW DIRECTOR]

Carnage would be an apt description of some of the things we experienced on the Heathrow side the last couple of days, thanks to the weather and a couple of emrgencies thrown in for good measure (who needs ECT?)

We managed to keep up a reasonable landing rate but it wasn't easy. The usual problems arose with pilots wanting to deviate round storms... I wonder about those guys who say "We must turn right in 5 miles, etc". OK - would you prefer to hit a cloud or a plane??!!

Why oh why will some pilots go straight through weather which others have to avoid by flying round half of southern England? In one case involving two BA 757s at the same level, five miles apart... one wanted weather avoidance and the other sailed merrily through! At the same time, some aircraft were quite happy to hold at BNN but one wanted a LH pattern... two others wouldn't go anywhere near BNN and ended up holding somewhere up near Luton!

We naturally sympathise tremendously and will do everything possible to help out (given that we have NO weather info on our radar). However, some sort of standardisation on weather avoidance among crews - especially among those of the same airline and same type - would help.

[halo]

Well done to the guys in TC yesterday with the way that the weather was handled. I was the catcher in the tower at LL for the first of the emergencies and it all went smoothly because everybody worked hard to share the information around. It must have been seriously hard work with the emergency and the crappy weather!! ():-)

[Flanker]

Vertigo

By 'comfort' I mean not scaring the crap out of the passengers even though usually there is no damage to the aeroplane.The problem is that you might fly through one red return with no real problem- but the next one might turn you upside down.You have to treat them all with respect.

It is a constantly changing environment so to get consistency in avoidance would be impractical.The first turn direction is often influenced by weather behind the first cell, preferably on the upwind side and obviously as close to the planned route as possible.

I agree its difficult for both parties but an early call is obviously in everyones interest if able.

I think you would agree you'd have to be a bit unlucky to turn without a clearance in the London area and hit an F15 or cherokee not xpding.By the way we are always looking out for (usually) light a/c flying around low level without their Mode C on and giving us Traffic alerts.

[Max Angle]

As others on this thread have said, ATC in the London area do a fantastic job when it turns to CB's. It does come down to the individual I think. I often look out and decide to fly through something that the a/c in front had steered around and get almost nothing. When it gets bad though you really do need to give them a wide berth. Often in the London TMA because of the radio congestion and the sheer volume of traffic it is impossible to get far enough away. We had 3 a/c struck by lighting in the space of an hour at LHR yesterday (16th). It is a rapidly changing situation and I think by and large, pilots and ATC work very well together to deal with it.

[HEATHROW DIRECTOR]

A few years back when the accursed "Sheds" used to fly into Heathrow we had some lousy weather one morning. This poor guy in a Shed had been bumping round BNN for 15-20 mins and asked "any idea how long before we commence an approach because it's wall to wall sick behind me". I'll always remember that when the wx is bad...!!

[Flybywyre]

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[This message has been edited by Flybywyre (edited 21 May 2001).]