PHOENIX -- It was 23 years ago this week (June 26, 1990) that airline pilots did not know if their planes had the performance to take off in the Valley of the Sun's 122-degree heat.
It wasn't that their aircraft couldn't fly in the high heat,. They just had no written information to confirm the performance. Their flight manuals, which give them take-off distances. were not written with such high temperatures in the equation.
Without that vital information, flights out of Phoenix Sky Harbor International Airport were grounded for a short time.
Since then, the manuals have been revised to include the high temperatures we experience here in desert Southwest, so there should be no flight delays due to the extreme heat this weekend.
Aircraft are just like humans. They don't like the heat any more than we do.
In hotter temperatures, the air molecules are not as dense, which will reduce the amount of lift a wing produces. When that happens, all performance is reduced, forcing aircraft to make longer take-off runs to get off the ground.
There were only slight delays 23 years ago when the airlines needed time to do the calculations that pilots used to take off in the record heat.