Ground deicing of aircraft

Aircraft flight characteristics are extremely sensitive to the slightest amount of surface irregularity, in particular that caused by frost, ice, or snow.

Such accidents include: Before every flight the pilot-in-command of an aircraft is responsible for inspecting the airframe for frost, ice, and snow.

[2] If frost, ice, or snow contamination is observed or suspected, the aircraft must undergo a deicing procedure before takeoff, using one or more of the methods listed below.

A complicating factor is that ambient atmospheric conditions may be such that contamination starts to build up again immediately after deicing is complete.

Typically this involves adding a viscous "anti-icing" fluid which will remain on the wings and immediately melt falling snow.

[7] Forced air can be used to blow off accumulated snow provided precautions are taken to avoid damaging aircraft components.

One infrared deicing system requires that the heating process take place inside a specially-constructed hangar.

This system has had limited interest among airport operators, due to the space and related logistical requirements for the hangar.

Even a thin layer of frost can severely impact flight performance so mechanical methods do not usually suffice on their own.

In particular the difference in temperature of the fuel in wing tanks and the ambient air can cause frost to form.

Commercial airports located in climates conducive to ground icing often have very elaborate deicing processes and equipment.

Typically deicing fluids are applied using a specialized vehicle similar to a "cherry picker" aerial work platform.

Large quantities of dissolved oxygen in the water column are consumed when microbial populations decompose propylene glycol.

[16]: 2–23 Sufficient dissolved oxygen levels in surface waters are critical for the survival of fish, macroinvertebrates, and other aquatic organisms.

Reductions in dissolved oxygen levels can reduce or eliminate bottom feeder populations, create conditions that favor a change in a community's species profile, or alter critical food-web interactions.