Lightning Strikes
Wednesday, October 12, 2011 at 07:16PM In the summer, especially in the South East and near coastal cities, lightning is almost a daily occurence. It may surprise you that it actually poses little threat to aircraft.
Strokes of lightning strike aircraft more than you may think. This mostly happens at lower altitudes and normally during take-off and landing. Often it is not possible to tell if the aircraft has taken a direct hit, instead pilots can report a lightning strike based solely on how loud the thunder is and how bright the flash is. When this does happen, there is not a lot of things that happen.
Typically, the aircraft diverts and lands at the nearest safe runway (usually the airport that is being departed to approached). Electronics do not flip out, pilots do not lose control, fuel does not ignite. Once on the ground, the aircraft is typically taken out of service and mechanics begin a "lightning check". This involves many mechanics inspecting the exterior skin of the aircraft for evidence of a strike then begin a tedious inspection of all the aircraft's electronics and hydraulics. This inspection may result in a blown fuse here or there - one of presumably many fuses that are incorporated into all levels of redundant systems. Once a thorough inspection is completed the aircraft is then reinstated to service usually 12-24 hours later.
In basic weather theory, pilots are taught how to recognize situations where lightning may be encountered. The biggest warning flag for lightning are the dangerous thunderheads that tend to develop during the course of a summer day until they release their immense amounts of energy in a very short amount of time. A bolt of lightning can, and will, strike as far as 20 miles away from these thunderheads - even if that area 20 miles away is under blue skies.
Another common place to find lightning is in squall lines preceeding a cold front. In front of a cold front is warm air that is holding mositure. Behind the front is cooler, more dense air that holds less mositure. As the cold air overtakes the warm air, the warmer air rises and the colder air replaces the warm air at the surface. This creates lifting action, and as the warm, moist air rises it cools and condenses. As it condenses it transforms from a gas to a liquid and precipitation begins. This is very much like how a glass of ice water sweats on the outside: the cool liquid inside the glass cools the air on the outside of the glass and as that air cools it loses the ability to hold as much moister in a gaseous state and releases it as a liquid.
When strong fronts of very cold air replaces very warm pockets of air, this process occurs faster and more intensely and produces extremely strong storms.
Reader Comments (1)
During a bad weather, flight schedules are usually postponed or cancelled to avoid unnecessary events. Safety should always comes first.