De-icing (None)

What Is De-icing?

De-icing is the ground procedure of applying heated fluid to aircraft surfaces — wings, tail, fuselage, and engine inlets — to remove accumulated ice, snow, slush, or frost before departure. Even a thin layer of ice or frost on a wing can dramatically alter its aerodynamic shape, reducing lift and increasing drag to levels that may prevent safe takeoff. The FAA and EASA operate a strict "clean aircraft concept": no aircraft may take off with frozen contamination adhering to any critical surface.

How It Works

De-icing is typically performed by ground handling specialist teams using heated glycol-based fluid sprayed from truck-mounted or elevated-platform sprayers. There are two stages:

• De-icing (Step 1): Heated orange or yellow Type I fluid (diluted glycol) at 60–82°C is applied to melt and remove existing contamination. This fluid has a short "holdover time."
• Anti-icing (Step 2): A thicker, longer-lasting green or orange fluid (Type II, III, or IV) is applied to prevent re-accumulation during taxi and initial climbout. Type IV can provide holdover times exceeding 80 minutes in light snow.

The flight crew tracks the holdover time and must take off before it expires, or return for re-treatment. The runway itself may also be treated with glycol or sand/urea to improve friction.

Types and Standards

• Type I fluid: Low viscosity, short holdover — used primarily for initial de-icing.
• Type II: Thickened fluid for anti-icing; not suitable for aircraft where V1 is below 100 kt.
• Type III: Intermediate viscosity for slower commuter aircraft.
• Type IV: Highest performance anti-icing fluid — longest holdover times; standard at major northern airports.

Interesting Facts

• Toronto Pearson Airport runs centralised de-icing pads remote from the terminal — aircraft taxi to designated pads, are treated, then proceed directly to the runway — improving efficiency and reducing runway occupancy.
• Airlines operating at Chicago O'Hare during winter storms may spend millions of dollars per season on de-icing fluid alone.
• De-icing fluid is toxic to aquatic life; airports collect spent fluid from pad drainage systems and recycle glycol content above 30% concentration.
• Air France Flight 358 (2005) and many other incidents have reinforced that incomplete de-icing or exceeding holdover times can be catastrophic — making checklist compliance non-negotiable.