Editing Freezing rain (section)

=== Aircraft ===
[[File:Wingice.JPG|thumb|Freezing ice on aircraft wing]]
Freezing rain is considered to be an extreme hazard to aircraft, as it causes very rapid structural [[Atmospheric icing|icing]], freezing necessary components.  Most [[helicopter]]s and small airplanes lack the necessary [[De-ice|deicing]] equipment to fly in freezing rain of any intensity, and heavy freezing rain can overwhelm even the most sophisticated deicing systems on large airplanes. Icing can increase an aircraft's weight but not typically enough to cause a hazard. The main danger comes from the ice changing the shape of its [[airfoil]]s. 
This will reduce [[Lift (force)|lift]] and increase [[Aerodynamic drag|drag]]. All three factors increase [[Stall (fluid dynamics)|stalling]] speed and reduce aircraft performance, making it very difficult to climb or even maintain altitude.

An aircraft can most easily avoid freezing rain by moving into warmer air. Under most conditions, this would require aircraft to descend, which it can usually do safely and easily even with a moderate accumulation of structural ice.  However, freezing rain is accompanied by a [[Inversion (meteorology)|temperature inversion]] aloft, meaning that aircraft are required to climb to move into warmer air, which is a potentially difficult and dangerous task with even a small amount of ice accumulation.

For example, in 1994, [[American Eagle Flight 4184]] encountered heavy air traffic and poor weather that postponed the arrival of this flight at [[Chicago]]'s [[O'Hare International Airport]], where it was to have landed en route from [[Indianapolis, Indiana]]. The ATR-72, a twin-engine turboprop carrying 68 people, entered a holding pattern {{convert|65|mi|km|abbr=on|order=flip|disp=or}} southeast of O'Hare. As the plane circled, supercooled cloud droplets, freezing rain or [[freezing drizzle]] formed a ridge of ice on the upper surface of its wings, eventually causing the aircraft's autopilot to suddenly disconnect and the pilots to lose control. The ATR disintegrated on impact with a field below; all passengers and crew were killed.