Is it safe to fly VFR at the moment?

[Tom Gale]

Volcanic Ash;
grounded from work at the moment.Is it safe to fly low level VFR at the moment?AIS and NOTAMS seem to suggest the pilot in command is responsible for that decision.Any thoughts on the matter?
Tom

[Norfolkjohn]

My thoughts :

1) Vast majority of ash is at hight altitude - 20,000' ish
2) All indications are that little or no ash is expected to reach ground level in the UK (all the health agencies say no health risk on this basis)
3) Airliners fly at 20K'+ we fly at about 2K'
4) A small gas turbine engine has a mass flow of around 200 - 300 Lb/s and a big gas turbine is sucking up to 2000 Lb/s. In other words a huge amount of air so if there are airborne particulates the gas turbine ingests far far more of them than a piston engine.
5) The particles in the ash can turn to glass in the conbustion and HP turbine sections of jet engines. This is not a realistic problem in light aircraft piston engines easpecially as the air going to the carbs is (normally) filtered.
6) Only significant risk to a small piston engine (that I can see) would be clogging of the air filter but refer to points 1) and 2).

Basically unless we start to see visible deposits either as low level clouds or as dust on the ground I can't see a real risk to VFR flight in a typical piston engine light aircraft operating at 2000 - 3000 feet.

Ordinary weather conditions permitting I hope to be flying tomorrow.

[Gaznav]

On Norfolk John's post

"Only significant risk to a small piston engine (that I can see) would be clogging of the air filter but refer to points 1) and 2). "

There is a risk of introducing air passed the air filter through use of Carb-Heat (unless your engine is fuel injected?). I guess I would sooner keep the venturi clear of ice, rather than worry about very small amounts of volcanic dust.

Also, please remember that if your filter does clog then the Carb-Heat knob gives you an option to bypass the filter.

It does beg the question why NATS is not allowing flights for airliners into and out of the UK FIR below 10,000ft - not very fuel efficient, but a genuine option. If I was stuck at an airport at the moment, I would be very grumpy if this was not being considered!

Gary

[Gaznav]

I know they wouldn't have enough fuel to go all the way at that height (I have about 500hrs on a CFM56 engined jet), however, they could probably transit to somewhere where there isn't an ash-cloud. For example, why don't the flights from London go to Prestick or Ireland, and then "gas and go" to the USA? I know it's more expensive, but at least it keeps them moving.

I just think that its all too easy to say - we can't fly, because...witout thinking of other options.

Gary

[Bob F]

I know using Carb Heat gives a way out if the filter is blocked, but that would allow the unfiltered "ash, or whatever it is" straight into the engine. Not good either.

[Bill McCarthy]

For goodness sake, you won't be flying into a snowstorm of the stuff. Talk of blocked filters and such like is just plain bonkers.

[Neil Moffat]

I drove to London and back over the weekend - about 800 miles in total, and my car is now covered with a fine, gritty deposit especially on the frontal surfaces.

Whether that would pass through a normal air filter I do not know, but I cannot see that it would do any good. The other issue is getting the stuff over cockpit transparencies which may not be an issue until you try to clean it off.

[macconnacher]

The question has to be asked why is this so bad when we often have grit all over our cars due to dust storms from the deserts of North Africa and we do not get worried. Surely sahara sand is the constituant of glass? If you have ever flown to Iceland you will see large dust storms due to a total lack of trees and wind erosion and the locals do not give up flying.
Better get the Volkes filters fitted to our Spitfires chaps!

[Neil Moffat]

Ron, I think you have the solution. Check the filters and replace/clean more often if necessary. I will be very careful cleaning my transparencies though.

I would be very happy if those 800 miles had only taken 12 hours!

[gasax]

Well I went flying on Friday afternoon - at 4 to 5 thousand feet the visibility was about 35 miles. The only thing that compromised things was the amount of heather buring which was going on. Some of the gliding chaps were talking about a strange taste in the air.

Was it the terrible volvanic dust or the raging heather fires? Who knows.

On Saturday I went and visited my mother. Dust was blowing from the fields as it was so dry, car now covered in dust but amazingly still running!

The present arrangements have all the hallmarks of 'elfin safety and yellow tabard jackets and nothing to do with intelligent thought.

Give it another couple of days and pressure from the airlines will allow a 'measured and careful re-appraisal of the situation' and they'll be flying again...........

[Bill McCarthy]

The muirburn period date has passed (15th) so starting heather fires now is illegal.

[gasax]

I'm sure the fires were actually started on Thursday!

But there is more hype and dis-information on this topic than most others.

The precautionary principle gone mad. Yes bad things can happen - worrying about a bogey man under the bed - or some huge potentiaql for damage hiding in 35 miles visibility.

If the Metoffice or NATS had sent a couple of aircraft into the plume and measured it in a systematic way I would believe. Instead we have a computer model and one(?) monitoring flight. And for that we are going to half bankrupt the airlines and when the protests get too loud we can say 'things are getting better'! ( now where did I hear that?).