744 FORUM (vertical frame)

deicing (Hardy?)

Posted By: Thorsten Mueller (fkpme231.uni-duisburg.de)
Date: 8 DEC 2004 - 09:51z

I am just preparing my winter PS1 OPSs and two questions came to my mind. I have already learned my lesson in PS1.2 (there was no deicing feature available), when I had engine failures on all engines after V1 during a T/O at EDDL. The failures were caused by ice built-up on the nacelles (although nacelle anti-ice was on) being ingested in the engines.

(1) When do aircrafts have to be deiced? The statement I know is: "Deicing is needed, when temperatures are below +10°C and visible moisture is present.". Is this correct? Are there any company specific guidelines?

(2) @ Hardy: What exactly happens, if I press the "De-ice the entire airplane" button. I assume that all ice built-ups are removed, but does this also provides me a time-frame, during which new ice build up is inhibited. In the real world, so-called holdover times (HOT) are declared, which indicate the maximum time allowed between deicing finishes and the T/O has to be started. These times strongly depend on the OAT, the type of precipitation, the fluid type used and the fluid/water mixture ratio. Some information on this topic can be found at: http://www.icao.int/icao/en/anb/opsair/groundice/. Just follow the links at the bottom of the page.

Thorsten (STV1080)
(10nm north of EDDL)

my GPPM pictures