It depends.
Anti-ice systems are designed to prevent ice from forming. Bleed air routed to the engine cowl would be an example of an anti-icing system.
De-icing systems are designed to remove ice once it has formed. Pneumatic boots affixed to the leading edge of a wing would be an example of a de-icing system.
You asked which one is best? The answer is the best system is the system that works keeping ice from where it should not be. The lowly beat up and patched pneumatic boots of a Piper Seneca that worked as advertised on their last flight are better than the high priced pitot tube heaters (original equipment) that did not do their job well on Air France’s Airbus flight 447 on its last flight across the Atlantic.
As with many questions in aviation the answer depends. It depends; are you talking about a piston powered twin flying unpressurized usually below 14,000 (FL140), are you talking about a wide body transport category turbojet flying 14 hour legs and half way around the globe, or are you talking about the Shuttle mission? Is the system being evaluated original equipment or an aftermarket add on? Is the evaluation criteria based on effectiveness or cost of installation and maintenance. Are you operating out of Madagascar (your post), the South Pacific or the Middle East where your exposure to icing would be much different than Scandinavia, Siberia or Canada in January/February?
Smaller piston powered aircraft generally use pneumatic boots because they lack an adequate source of high temperature and pressure air. The weight associated with the necessary tubing and valves would be a limitation as well. The de-icing systems on smaller piston powered aircraft generally use small air pumps and associated tubing. Sometimes they use electricity to heat surfaces (props & windshields).
Turbojets often use high pressure/temperature bleed air for their anti-ice needs. The maintenance issues surrounding rubber or composite boots and high speed flight usually preclude their application [IA-Jet 1124 (Westwind) notable exception].
Anti-ice fluid and weeping surfaces have been used as well. Each system has its limitations and advantages.
To ask what the best anti-ice system is; is like asking what the best tool is. It depends on the nature of the job and the limitations one must consider.
The best anti-ice system is the system that works exactly as designed when you need it the most.
Each system had its reason for design and deployment. Every system needs to be properly installed, maintained and inspected. And every system needs to be understood and operated correctly within its design limitations to be effective. I will go with FlightSafey’s motto here: the best safety equipment in an airplane is a well trained pilot. What is the best anti-ice system? Besides the system that works correctly I would add a well trained, experienced pilot making good decisions is pretty important as well.
Which one of the following system is the best for anti icing and what are the advantages compared to others ?
*Fluid based system
*Pneumatic de-ice boots
*Electrothermal de-ice system
Fluid based systems. Advantages you do not have to deal with pneumatic pumps or the ongoing patching requirements of de-ice boots. But you have to locate a reliable source of the de-ice fluid and sufficient quantities must be stored.
Pneumatic de-ice boots well understood system widely used. Parts are usually available, but the system requires more ongoing inspection and maintenance efforts.
Electro thermal de-ice systems are generally lighter and do not have the ongoing maintenance and storage issues related with fluid based systems.
Last edited by Northbeach; 30th Jan 2012 at 19:50.