Q: What is the pink liquid used to de-ice snow-encrusted planes? And what about in the air? How do planes de-ice themselves during flight?
The delicious looking fluid (apricot-strawberry) used for ground de-icing is a heated combination of glycol and water. There are different mixtures for different conditions, varying in temperature and viscosity. It helps remove existing material and prevents the buildup of more. How long a plane is good for after application is not just a matter of giving it a look-see, but follows something called “holdover time,” accounting for the rate and type of current precipitation and ambient temperature.
The fluid is often collected and recycled, but at $5 per gallon de-icing a plane is extremely expensive. When handling, storage and disposal costs are considered, relieving a single jet of unwanted ice or snow can cost tens of thousands of dollars. Making a messy situation worse, glycol is toxic. What does our de-icing future look like? It looks like a hangar: at a few airports planes are steered through enclosures that use infrared heat instead of fluid. Continental now uses a facility like this at Newark.
All airliners are equipped with onboard gear to deal with the stuff encountered aloft. On smaller planes, pneumatically inflated boots will break ice from the leading edges of wings and stabilizers. On larger planes the wings, engine inlets and a few other spots are heated using air bled from the engine compressors. Windshields and various probes are kept clear electrically. These systems use redundant sources and are separated into independently operating zones to keep a failure from affecting the entire plane.
Offhand, I can’t cite a single case of a large plane crashing from ice that accrued during flight, but there have been a handful of takeoff accidents over the years, most notoriously the one involving Air Florida flight 90 in Washington in 1982. In addition to buildup on the wings, iced-over engine probes gave a faulty, less than actual thrust reading after the crew had failed to run the engine anti-ice system. The most recent serious crash, a more true-to-form ice on the wings scenario, was that of a USAir Fokker jet at La Guardia in 1992 (24 of the 51 occupants survived). Not bad, considering there have been about 12 million takeoffs in the country since then.
This article is part of a collection that originally appeared on Salon.com. Patrick Smith, 38, is an erstwhile airline pilot, retired punk rocker and air travel columnist. His book, Ask the Pilot (Riverhead) was voted “Best Travel Book of 2004” by Amazon.com. Patrick has traveled to more than 55 countries and always asks for a window seat. He lives near Boston.