[Maalie]

Quote

Big Dave's Gusset - 17/5/2010 19:20

It's the transponder code, usually assigned by ATC. The transponder receives an radio frequency interrogation request and gives out the ID for radar on the ground or in-air collision avoidance.

 

Ah! Many thanks BDG!

[John Robert Mellor]

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StephenS - 17/5/2010 14:40

. So I do think our perception of risk here needs to be re-evaluated.

The restriction goalposts have already been revised at least twice as far as I know, including very recently, and agreed by the operators, and yet when these new agreed parameters are breached, and therefore no fly restrictions are put in place, the operators are throwing their toys out of business class and kicking up a fuss.  it appears they don't want any no fly zone restriction agreement to stand....if its going to cause financial / customer apathy.

 

[PJB]

~Interestingly the 12Z Issued COncentration graphics have removed the dense ash from Southern Britain completely. I hope this has been based on Soundings and Lidar rather than airlines.

[durou]

Looking at the Norwegian ash forecast, the most dense area has just moved off the coast at noon. I'm not sure where the goalposts have been placed now as far as safe levels in mg/per sqm. France seems to be operating at muc higher levels than the UK so who knows.

http://transport.nil...p=conccol_VO_1_

[PJB]

CAA just announced that Limits are being increased =again= from tomorrow... just breaking on BBC News - not seen anymore details on this.

[P.K.]

Looks like they've changed the rules for a 3rd time now.

New guidance clears the way to fly through ash cloud

Monday 17 May, 1800

NATS is delighted that restrictions on UK airspace can today be eased, thanks to new measures from the Civil Aviation Authority.

Aircraft can now safely fly through ‘medium density’ ash following the introduction of a new zone that defines the concentration of the ash cloud.

“NATS has been at the heart of this ground-breaking proposal and our people have worked very closely with the Irish Aviation Authority, CAA and the rest of the industry to make it happen,” said NATS Chief Executive Officer, Richard Deakin.

“Every leading player in aviation has been helping to build vast amounts of data about the effects of volcanic ash over the last month. There is mounting evidence that aircraft can fly safely through areas of medium density, provided some additional precautions are taken. This is now what has been agreed.”

Richard added that teams at NATS had been working all hours to create new and enhanced procedures to make sure the changes can take place as safely and as effectively as possible. 

Previously, the CAA has dealt with the ash cloud by applying No-Fly Zones (NFZ) in areas of greatest ash density, and Enhanced Procedures Zones (EPZ) in areas of low density, which were introduced during the six-day crisis last month. 

Today’s breakthrough means a third Time Limited Zone (TLZ) is now being introduced for areas of medium ash density.  

As a result of this change, there are no predicted restrictions on UK airspace in the immediate future. If that picture changes, NATS will update its website as necessary.

http://www.nats.co.uk/

 

[Cliffyboy1962]

As simple as that. It's not a problem anymore. Smells fishy to me.

[Dave W]

I think a plane really WILL need to fall out of the sky to be honest..

[PJB]

A bit more detail from CAA

The UK Civil Aviation Authority (CAA) today reports a positive outcome from discussions with airlines, regulators, and aircraft and engine manufacturers resulting in new measures to reduce airspace closures caused by volcanic ash. These new measures will be available from midday tomorrow.

A new area of operations can now be introduced that creates a ‘Time Limited Zone (TLZ)’ between the black ‘No Fly Zone (NFZ)’ and the red ‘Enhanced Procedures Zone (EPZ)’. Aircraft and engine manufacturers, based on new research and analysis, have agreed that it is safe to allow operations in the new zone for a limited time at higher ash densities than is currently permitted.

To operate in the new zone airlines need to present the CAA with a safety case that includes the agreement of their aircraft and engine manufacturers. UK airline Flybe is the first to achieve this and will therefore be able to use the new zone from midday tomorrow.

This means that areas of our airspace that would have previously been closed can safely open, further minimising flight disruption.

Announcing the change Andrew Haines, Civil Aviation Authority Chief Executive, said: “I’m pleased that the huge efforts we’re all making across aviation to keep flying safe whilst minimising the disruption from the volcano have resulted in further progress. Unprecedented situations require new measures and the challenge faced should not be underestimated. Firstly because the standard default procedure for aircraft that encounter ash, to avoid it completely, doesn't work in our congested airspace. Secondly, the world’s top scientists tell us that we must not simply assume the effects of this volcano will be the same as others elsewhere. Its proximity to the UK, the length of time it is continuously erupting and the weather patterns are all exceptional features.

"The answer can only come, therefore, from aircraft and engine manufacturers establishing what level of ash their products can safely tolerate. At an international aviation conference we held last Thursday, attended by all the leading airline operators this approach was welcomed and supported. The manufacturers are co-operating fully and urgently in this task and the new zone is an excellent example of how the industry should be working to move the issue forward and I commend Flybe for its work.

"It's the CAA's job to ensure the public is kept safe by ensuring safety decisions are based on scientific and engineering evidence; we will not listen to those who effectively say 'let's suck it and see."

The introduction of the Time Limited Zone is based on measurements collected from test flights through the current ash cloud over the past month, as well as on data and evidence compiled and analysed from previous volcanic ash incidents combined with additional analysis from manufacturers.

Operations in the newly established Time Limited Zone may be subject to time limits and increased maintenance practices. The new Zone’s area will be established using Met Office forecasts, and will be approved by the CAA before operations are allowed within it.

The CAA will maintain its focus on the public interest by bringing the industry together to facilitate safe operations. Already over the past month there has been much learning from the combined efforts of operators, manufacturers, NATS, other regulators, forecasters from the Met Office, volcanologists and research agencies and this will continue.

For more information contact the CAA Press Office on 020 7453 6030 (out of hours 01293 567171) or press.office@caa.co.uk

[Cliffyboy1962]

I just hope that aircraft and engine manufacturers are not being put under pressure from the airlines, to raise the ash tolerance levels.

It's not impossible to imagine airlines reminding manufacturers, that the implications of not raising tolerance levels would mean ultimately, dramatic reduction in planes being purchased and hence being very bad for business, for the whole of the aviation industry.

Can we trust businesses to put safety before profit, or, as it could mean for some, survival ? 

I am not sure i feel comfortable with that.

Can the CAA not get advice from impartial, independent experts (If there are such people)

I mean, you wouldn't ask drug dealers to advise as to whether their products are safe for human consumption, would you ? "Errr yeah mate, cocaine is actually really good for you"

[Andy Mayhew]

So has anyone got a good reason why this couldn't have all been agree in March?  Or, indeed, before then?

After all, not as though anyone was not expecting this ....

http://www.paris.ica...0-%20ISAVIA.pdf

[EllyTech]

A personal and unscientific observation I've made is that industry and the public have about a week's tolerance threshold for disruption to daily routine and lost revenue. The eruption could go on for a year. Planes will now fly where previously, ash safety thresholds would rule against. How long before the ash observations become passe; when we forget or push this away from focus? How long then, before something simple, such as a rushed or missed inspection or miscalculation of ash concentrations and/or accumulative engine damage, result in disaster?

:(

How do pilots feel? Pilots change planes with each flight so none of them would know the exact 'history' of the aircraft they fly.

Perhaps I speak out of turn and to be honest, it would be better if that is the case as aviation experts know best. And, taking comfort from that fact is something we need to be able to trust in.

[John Mason]

A funny (not ha-ha) observation is that today has been lovely and sunny. Ten times out of ten this typically means we get the daily airshow from the military circuiting the Mach Loop. Today: not one jet!

They come from various bases e.g. Hawks from Valley on Anglesey, F15s from Lakenheath in E Anglia and so on. I wonder why they've stayed put (apart from the obvious observation that military jet engines operate at much higher velocities of air and potentially ash intake)... 

Cheers - John 

[EllyTech]

"New rules to allow planes to fly at higher ash densities for a limited time will be introduced at noon on Tuesday, the Civil Aviation Authority has said."

http://news.bbc.co.u.../uk/8688517.stm

[PK2]

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EllyTech - 17/5/2010 22:52How do pilots feel? Pilots change planes with each flight so none of them would know the exact 'history' of the aircraft they fly.

From what I've read some feel the same way as Welsh (who I understand is a pilot), in that as long as one avoids visible ash clouds (which may mean flying only during the daytime) there shouldn't be a problem. Of course there are others who feel different.

[Andy Mayhew]

Part of the problem is surely that UK airspace is far more crowded than that of Alaska and Washington State with a large number of airports very close to one another.  It's therefore not such an easy matter to just 'fly around' any visible ash cloud that may exist over a part of UK airspace - as seems to have been the case

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scrapemedic - 16/5/2010 19:33 Peter Gibbs on BBC News channel saying that a pilot "met the ash cloud at the North Yorkshire coast, and the pilot reporting that 'no one should fly into that cloud'", and that the cloud was 10000 foot deep.

What can safely be done in the USA may not be appropriate in the UK.

 

[PJB]

New Graphics from the Met Office... 12Z today have the Red, Grey and Black Zones on them

[Dave W]

It must be said that if the zoned density info was available before it would have surely be useful to include it.

[Dave K]

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Andy Mayhew - 18/5/2010 07:49

Part of the problem is surely that UK airspace is far more crowded than that of Alaska and Washington State with a large number of airports very close to one another.  It's therefore not such an easy matter to just 'fly around' any visible ash cloud that may exist over a part of UK airspace - as seems to have been the case

Quote

scrapemedic - 16/5/2010 19:33 Peter Gibbs on BBC News channel saying that a pilot "met the ash cloud at the North Yorkshire coast, and the pilot reporting that 'no one should fly into that cloud'", and that the cloud was 10000 foot deep.

What can safely be done in the USA may not be appropriate in the UK.

 

Something I said before...

The area of the United Kingdom is approx 95 000 square miles. Washington State is approx 70 000 square miles and Oregon is actually 1 000 square miles larger than the United Kingdom.  So closing down the whole of the UKs international airports can be seen as equivalent of affecting only 1 fair size state of the union, with just a very few busy international airports such as Seattle and those very much more spaced out than ours.