The Anonymous Widower

I Wish I Still Had Delta-Delta

Delta-Delta was my Cessna 340A.  This was a six seater twin piston engined aircraft.  So could I still fly the aircraft with all this volcanic dust about.  There is a good technical article called How Volcanic Ash Threatens Aircraft  in New Scientist, which explains all the problems very well.

Volcanic ash is composed of particles of glassy pulverised rock less than 2 millimetres in diameter. When an aircraft flies into it at its high cruising speed, the cockpit windows get a sandblasting, obscuring the pilots’ view. Crucially, though, the engines suck the dust in, where it melts in the hot combustion chamber and fuses to form globs on the turbine vanes that block the engine airflow. Only when it cools and solidifies – as the aircraft plummets engineless – can enough of the muck flake off to allow an engine restart.

So that convinces me as an ex-pilot with over a 1,000 hours on the clock, that the authorities are not being over cautious.

But it is this comment on the article that is interesting.

There isn’t a blanket ban on flying in the UK. AIUI, NATS has closed controlled airspace. You are allowed to fly outside controlled airspace, and planes can fly ‘VFR’ (Visual Flight Rules) which are more restrictive than ‘IFR’ (Instrument Flight Rules) (eg for VFR you have to fly slower, and within sight of the ground). For IFR you have to be in touch with air traffic control, for VFR you don’t (as long as you are outside controlled airspace), you just do your own thing.

So, a Cessna can probably fly fine under VFR at the moment, while a 747 can’t. Similarly, gliders, paragliders will all be fine, since they always fly VFR, and rarely go into controlled airspace.

Theoretically, I suppose, something like a 737 could fly VFR within the UK (they have been known to if controlled airspace is busy), but would have to land at airfields outside of controlled airspace, and there aren’t many of those big enough to take that size of plane.

Also, a jet engine is much more susceptible to problems from ash than a (non-turbo) prop plane is.

A light aircraft prop engine has pretty much just a (very powerful) engine with the same technology as a car, so it has air filters which will protect it from dust (as long as you don’t overuse the ‘carb heat’ function), and light aircraft don’t go fast enough for dust to have a significant abrasive effect.

So Delta-Delta could fly VFR at least in the UK.  The last point is the most important.  A piston-engined aircraft should be protected from dust ingestion.

Whether I could rescue all my mates stuck in foreign parts, I do not know.  It would just depend on the rules on the continent.

April 17, 2010 - Posted by AnonW | News, Transport/Travel | Flying, Volcanoes