In the immediate aftermath of Hurricane Katrina's massive assault, it would seem that the overall effects of the storm on our airline system (other than closed or damaged Gulf Coast airports) would be minimal.
But there are two truths that every user of the airline system needs to understand when large storms rage across the nation:
First, the airline system is so intricately interconnected that disruptions in one area will always affect schedule and service in all areas to some degree; and secondly, Mother Nature still rules when it comes to aircraft and large storms -- in any misguided contest between the two, aviation will usually lose.
That second point is the reason that airports such as Louis Armstrong New Orleans International Airport are shut down and all the aircraft flown away as fast as possible when a major hurricane approaches. Trying to fly even something as big as a Boeing 747 in gusty winds above 50 knots or in heavy rain in the vicinity of a hurricane or even a major thunderstorm is a very bad and inherently dangerous idea.
Most jetliners, for instance, have a maximum crosswind limitation of 25 to 30 knots (meaning the maximum effective wind drift left or right across a runway a flight crew is trying to use). The reason for this is the difficulty of keeping the aircraft's wheels safely on the concrete when it's slickened with heavy rain and the wind is trying to blow it sideways.
Hurricanes in particular spawn unpredictable gusts, lightning, massive dumps of water on runways, as well as severe turbulence, wind shear, and damaging hail -- not to mention tornadoes, and obviously airplanes do not mix well (or safely) with any of those characteristics, even when sitting on the ground. In fact, a modern aircraft can be severely damaged by nothing more than large hailstones hitting it at the gate. And for an empty jetliner capable of becoming airborne at around a hundred knots of wind, the prospects of keeping it safely on the ground in wind gusts above a hundred is unlikely.
But point one about the interconnected nature of the airline system is something many of us still miss. When you're sitting beneath a beautifully clear sky in San Diego, for instance, it's a bit difficult to recall that the fury being visited on Louisiana may also mess up a third of California's inbound and outbound flights, causing delays and cancellations.
But why is that, when Louisiana doesn't have a major hub airport like Atlanta or Chicago?
This storm in particular is so massive that it's affecting air lanes across the southern half of the nation, as well as Memphis, Tenn., (which is a major hub) and Atlanta. The problem, however, is not so much getting our transcontinental flights past Katrina as much as the scramble of crews and airplanes that occurs in a huge airline when schedules can't be flown as planned.
Of course, flights to New Orleans were suspended early, and that encompasses only a finite number.