ICING PROCS FOR ATR ACFT.

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THIS DEALS WITH THE FACT THAT I THINK ATR ICE PROCS ARE DANGEROUS. THE ATTACH LETTER WAS SENT TO FLT SAFETY AS I HAVE AN ASSOCIATE THAT WORKS THERE. I WILL REPEAT THE QUESTIONS HERE: AT THE FIRST INDICATIONS OF AIRFRAME ICE WE TURN ON THE AIRFRAME DE-ICE. I NOTICE WHEN IT FIRST STARTS TO ACCUMULATE NONE OF IT COMES OFF. WHAT STOPS THIS FROM BECOMING PARASITE ICE? MOST OF MY 20000 HRS IS IN THE 'CLE' AND 'ORD' MARKETS. ALL OF MY PREVIOUS EQUIP F-27; EMB120; AND ASSORTED OTHERS; ALLOWED THE BUILD-UP OF 1/4 INCH TO 1/2 INCH OF ICE PRIOR TO EXERCISING THE AIRFRAME BOOTS. ATR SUGGESTS AND IS OUR PROC TO EXTEND 15 DEGS FLAPS IN MODERATE OR SEVERE ICE. WHAT STOPS THE BUILD-UP UNDER THE WING FLAPS OF PARASITE ICE. I THINK THIS IS THE ONE THAT KILLED '(FLT NUMBER).' WHEN FLAPS ARE 15 DEGS IN MODERATE OR SEVERE ICE WHAT STOPS THE JACK-SCREW SHROUD FROM FILLING UP OR BINDING UP WITH ICE. THEREBY BINDING BOTH FLAPS; OR WORSE 1 SIDE ONLY INTO A BOUND SIT. OUR F-27 AND F-227 HAD SIMILAR AIRFRAME DE-ICE SYS TO ATR 42-72. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: PLT FEELS THE SYS ANTI-ICE WORKS VERY WELL. MOST PROBS OCCUR BECAUSE THERE IS MUCH MISUNDERSTANDING OF THE APPLICATION OF THE ICE HANDLING SYS. BIGGEST PROB IN HIS VIEW IS THAT MOST PLTS TREAT THE AIRFRAME ANTI-ICE AS AN ANTI-ICE SYS WHICH IT IS NOT. IT IS A DE-ICING SYS AND SHOULD BE USED IN THAT MANNER. IE; ONLY TURN IT ON WHEN ICE HAS FORMED; NOT BEFORE IT DOES FORM. HE FEELS ALSO THAT TOO MANY PLT HOLD IN ICING CONDITIONS WITH THE FLAPS PARTIALLY EXTENDED ALLOWING ICE TO FORM ON THE FLAP CTL MECHANISM. THIS CAN PREVENT THEIR EVEN RETRACTION OR FAIL THEM IN THE EXTENDED POS. ANOTHER POINT HE FEELS IS OFTEN VIOLATED IS USING GOOD JUDGEMENT OF HOW LONG TO STAY IN ICING CONDITIONS. HIS OWN RULE IS IF IN HVY ICING FOR 30 MIN; CHANGE TO ANOTHER AREA TO GET OUT OF IT. PLT HAS GREAT CONFIDENCE IN THE RELIABILITY OF THE ACFT TO FLY SAFELY. HE DOES NOT FEEL ACFT NEEDS REDESIGNING; JUST THE USE OF APPROPRIATE PROCS AND THE FOLLOWING OF THEM IS ALL THAT IS NEEDED.