"Orval Fairbairn" wrote in message
news
In article ,
Philip Sondericker wrote:

in article fT27d.3595$mS1.2578@fed1read05, BTIZ at

wrote on 9/30/04 7:00 PM:

that would be one heck of a thermal ride... if it weren't for the
rocks...
and "cough cough" the ash..

BT

I was thinking about this recently, and I was trying to determine
exactly
what the effects would be on a small plane flying into an ash cloud. How
long would it take for the air filter to become completely clogged? And
at
that point, assuming the plane had a carburetor, what would be the
effect on
the engine? Would the plugs become fouled? Would they fire at all?

I'm a new pilot and relatively ignorant of engine operations, so I'm
curious
to hear the answers.



You can count on an early overhaul, at best. During the 1980s, several
turbine aircraft, including a B747, encountered ash clouds in flight.
The ash is so abrasive that it eroded the compressors to the point of
flameout. The B747 descended to ~10000 ft before they got three engines
relit. A C130 had similar problems.

New Zealand-based pilots , especially those close to the central range on N
Island, have to deal with ash from time to time. When I visited in 1997, our
747 was sent from Auckland airport an hour early because Ruapehu was acting
up. Any Kiwis here can comment?

-- David Brooks