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PIK1967
2nd Apr 2004, 15:29
Hi.Have just finished reading Paul Craigs "The Killing Zone"
For those not conversant with the book,it is by an American author,who has researched G.A. accidents in the States.
Basically he states(by figures)that the majority of fatal accidents occur between having 50-350hrs flight time experience-i.e.The Killing Zone.
On the whole it is worth a read,but the point of this thread regards what he says on the chapter on weather and in particular Carb ice
Quote
"I always operate with continuoes Carb Heat on when I am flying in visible moisture or cloud,rain etc.I also operate continuoes Carb Heat when the temp and dewpoint are within 5degrees of one anotheror relative humidity is above 90%
I was always taught that Carb Heat should only be used in moderation,i.e. FREDA checks,on approach(low RPM settings)and if you had a rough running engine.
I`m sure I also read a thread here that excessive Carb Heat could be a hazzard.
Not knocking the guys experience(flight instructor),but any comments anyone?
Safe Flying,
Bob.

Saab Dastard
2nd Apr 2004, 16:13
PIK1967,

I don't want to appear rude or abrupt, but this book has been discussed in this forum a few times before. As indeed has the topic of carb heat.

Now that "Search" is re-enabled, perhaps you might care to do a search for "The Killing Zone", and Carb heat.

I hope I haven't put you off posting again!

SD

MLS-12D
2nd Apr 2004, 16:56
Doubtless someone will disagree with me, but personally I don't see anything wrong with using continuous carb heat as a prophylactic measure in conditions likely to lead to carb icing. The air going into the engine will be unfiltered, but that shouldn't matter in flight (as opposed to ground operations). Engine efficiency will be slightly reduced, but that too shouldn't matter very much in cruise (I would not recommend leaving carb heat hot while on finals, in case a go-around is necessary).

See here (http://www.pprune.org/forums/showthread.php?s=&threadid=106871&highlight=carb+heat) for the PPRUNE thread on the use of carb heat. For other discussions, see here (http://www.cessnaowner.org/cgi-bin/phorum-3.4.1/read.php?f=1&i=5456&t=5456) and here (http://whitts.alioth.net/Pagea9Carburetor%20Ice%20and%20Heat.htm).