Extreme heat could delay Phoenix flights

Airlines won't proactively cancel hundreds of flights, stranded travelers won't be camped out at the airport overnight and no runways will have to be cleared — scenes that play out every time a major winter storm wallops the Midwest or East Coast.

But the extreme heat forecast for greater Phoenix early next week is no different for airlines and Sky Harbor International Airport than a blizzard in one respect: Advance planning is key to make sure things go smoothly for travelers and employees.

With temperatures forecast to hit 120 degrees on Tuesday -- just two degrees shy of the record 122 degrees that temporarily grounded Phoenix flights in 1990 -- preparations are already under way.

American Airlines on Saturday alerted travelers to the coming heat and recommended they change - free of charge - any flights schedule to arrive or depart between 3 p.m. and 6 p.m. Monday, Tuesday or Wednesday. 

The high temperatures, the airline warned, "could impact flight operations." 

And the hottest U.S. city is in ... wait, you really don't know?

American, which has nearly 300 workers per shift loading and unloading bags from planes, plans to stock its roving golf carts with coolers full of ice and water for workers on the ramp.  This is in addition to standard summertime staples such as hydration carts, "cool zones'' with portable swamp coolers and canopies and surprise treats that have previously included food trucks scooping out shaved ice.

"It's going to be hotter than normal, so obviously there is concern for our employees,'' said Kevin McCarthy, manager of customer operations. "What we'll do is try and make it as comfortable as possible and do everything we can to make our folks comfortable.''

Sky Harbor will add hourly breaks for the 400 employees who work outside as part of their job, directing traffic at the curbs, landscaping and doing airfield maintenance. They usually get two 15-minute breaks during their shift. Some shifts will be adjusted to avoid peak daytime heat.

"If I've got a roof leak that needs work, I'm not going to send someone up there when it's over 110 degrees,'' said Bobbi Reid, acting assistant director for operations and facilities at Sky Harbor.

Reid worked in passenger services and ramp services for Tempe-based America West Airlines on June 26, 1990, and vividly recalls what it was like on the ramp that day.

She was interviewed by a television station near a plane parked at Terminal 3.

"We had an asphalt ramp at the time,'' Reid said, noting that the same ramp is concrete today. "It was so hot in the asphalt that my pumps were actually sinking.''

Reid recalls America West's Boeing 737 flights being grounded for about 90 minutes that day. Southwest Airlines also temporarily grounded flights. The two carriers are the airport's dominant airlines.

Sky Harbor was never closed that day.

Flight delays happen in extreme heat because higher temperatures affect aircraft performance. A big factor: higher temperatures thin the air, allowing less air to flow through the engines, producing less thrust. This also affects aircraft weight, takeoff speed and required runway length, according to Ron Carr, a former American Airlines pilot who is now associate professor at Embry-Riddle Aeronautical University in Prescott.

Carr said any delays likely would occur during the hottest part of the day.

"Late afternoon is probably when you see some delays,'' he said.

Regional jets used by commuter carriers including American Eagle are likely to incur more problems than larger jets. Aircraft manufacturers provide flight performance data for each type of plane, including varying temperature and air density levels.

Back in 1990, the manuals didn't include guidelines on what to do at 122 degrees, causing confusion and some of the delays. The figures have been updated since then to include temperatures as high as 127 degrees depending on the aircraft, but data for regional jets generally don't go past 118 degrees.

American is monitoring the situation closely and still crafting its operational plan ahead of the heat wave, spokesman Ross Feinstein said. 

McCarthy said one thing is certain: as temperatures creep towards 120 degrees, travelers should high-five a ramp worker if they run across one of them on break in the airport next week. They wear bright vests.

"Thank that person for being out there and making sure your bag is getting on the airplane and your flight departs safely,'' he said.