mmaviator

Can some explain to me with a source bout the correct way to use deice boots. I read awhile a ago that it doesn't matter when you use them during ice accumulation as long as you use them. Then I hear that you have to wait for ice to build enough for the deice boot to kick it off. Just a little confused and have never flown an aircraft with boots. thanks

mmaviator

MODS.....

can you delete this thread. found this doing some searching.


************************************************** **********
NTSB PRESS RELEASE
************************************************** **********

National Transportation Safety Board
Washington, DC 20594

FOR IMMEDIATE RELEASE: December 18, 2008
SB-08-58


************************************************** **********

NTSB ISSUES SAFETY ALERT ON OPERATING AIRCRAFT IN ICING
CONDITIONS

************************************************** **********

Washington, DC - The National Transportation Safety Board
issued a Safety Alert titled "Activate Leading-Edge Deice
Boots As Soon As Airplanes Enter Icing Conditions."

"This Safety Alert, directed to the pilot community, is
intended to increase the visibility of airplane icing issues
and address procedures taught regarding the accumulation of
ice before activating deice boots," said NTSB Acting
Chairman Mark V. Rosenker.

Some of the highlights of the newly issued Safety Alert,
which was approved by all five Board Members, are:
* noting that as little as 1/4 inch of ice can be deadly;
* as little as 1/4 inch of leading edge ice can increase
the stall speed 25 to 40 knots; and
* early activation of the deice boots limits the effects
of leading-edge ice and improves the operating safety
margin.

The Safety Alert states that leading-edge deice boots should
be activated as soon as icing is encountered, unless the
aircraft flight manual or the pilot's operating handbook
specifically directs not to activate them.

In the Alert, pilots are instructed to maintain extremely
careful vigilance of airspeed and any unusual handling
qualities if the aircraft manual or the pilot's operating
handbook allows for an accumulation of ice before activating
the deice boots, and to turn off or limit the use of the
autopilot in order to better "feel" changes in the handling
qualities of the airplane.

"When followed, this Safety Alert will create a safer
environment for pilots flying in icing conditions," Rosenker
stated.

NightIP

Just to add a little bit to the thread, it's really airplane specific. In the C402 you won't get anywhere by blowing the boots until you have at least 1/4" accumulation. It's actually recommended by Cessna that you don't blow them until 1/4-1/2" is built up, as well. The boots are simply too slow to knock the ice off until that level of accumulation.

Now an airplane with a newer boot system? The FAA's recommendation might work pretty well. Check the AFM.

pokey9554

Typically, this information can be found in the AFM. In some of the older turboprops I've flown, the manual stated not to blow the boots until 1/4" of ice has accumulated. The reason for this, is at the begining of ice accumulation, the ice may not be rigid enough to break apart and remove itself from the wing, but instead conform to the shape of the leading edge with the boot inflated. The result is ice accumulation beyond the reach of the boot.