The Importance Of Weather In Aviation

Weather is the cause of approximately 70 percent of the delays in the National Airspace System (NAS). Weather has and will continue to play a significant role in a number of aviation accidents and incidents. National Transportation Safety Board (NTSB) reports that human error is the most common cause of direct aviation accidents, however weather is a primary contributing factor in 23 percent of all aviation accidents. The total weather impact is an estimated national cost of R30 billion for accident damage and injuries, delays, and unexpected operating costs.
Convective weather is a hazard to the aviation industry. Majority of warm season delays are a result of convective weather. There are many convective aspects that may hinder flight operations

During periods of extremely cold temperatures resulting in freezing precipitation and other icing conditions, aircraft whether stationery on the ground or moving along runway surfaces are vulnerable to a build of ice on control surfaces, instrument orifices and engine inlets. Even thin layer of ice on the surface of the wing can increase drag and reduce lift by 25 percent. This type of icing was the cause of 10 commercial aircraft accidents between 1978 and 1997. Ice can also block airspeed and altitude measurement instrumentation which can result in pilots getting faulty readings in the cockpit. This ultimately causes a loss of control and navigation

Icing occurs when an aircraft flies through visible water and the temperature at the point where the moisture strikes the aircraft is 0° or colder. Supercooled water increases the rate of icing. There are 3 different types of ice that form on the structure of the aircraft. Clear ice freezes as a smooth sheet of solid ice. It is hard, heavy and difficult to remove. Rime ice is lighter in weight and has a rough surface. It is brittle and easier to remove. Mixed ice forms a mushroom shape on the leading edges of the wing and form a hard, rough-edged mass. NTSB concluded that in the years 1989-1997 in-flight icing caused 3 percent of all weather related accidents in commercial aviation. In-flight icing is dangerous and impact the efficiency of flight operations as well as leads to late arrivals. Icing on the structure of the aircraft increases aircraft weight, reduces lift, produces false instrument readings and compromises control of the aircraft. Another danger ice poses is known as mechanical icing which occurs in carburettors, engine air intakes and fuel cells. Mechanical icing impairs engine performance leading to reduction of power. Freezing rain with a cold front will cause icing. All clouds with sub-freezing temperatures have the potential to create icing conditions. Icing is most hazardous in the case of being in a mountainous region. This type of icing has a process where rapid movements of upward air together with