Midway through a flight to South Bend, Ind., an Allegiant Air plane turned around and headed back to the St. Pete-Clearwater International Airport. The plane's air conditioning wasn't working, and the cabin was too hot to continue, according to Allegiant. By the time it landed in Pinellas County, multiple people had fainted.
"I don't sweat and I was dripping," said Karen Willey, a Bradenton resident aboard the flight.
The incident is one of dozens of Allegiant flights since June 1 that consumers — and an incident report from a local fire and rescue department — say did not have adequate air conditioning for some or all of the flight. It ultimately caused some passengers to pass out.
On June 22, St. Petersburg Fire and Rescue met the Indiana-bound plane at the gate to provide medical attention. According to the agency's incident report, two people were treated for symptoms related to overheating, and both declined to be taken to the hospital. However, Michele Routh, public relations director for the St. Pete-Clearwater airport, said four passengers were treated for heat-related issues.
A cooling valve that malfunctioned during flight was the root of the issue, Hilarie Grey, spokesperson for Allegiant, said.
Allegiant Air is the dominant carrier at St. Pete-Clearwater International Airport, accounting for 95 percent of all passenger traffic. The airline continues to expand there, shattering the airport's passenger records nearly every month, and offering service to more than 50 destinations in the United States from St. Pete-Clearwater.
The Las Vegas-based airliner has been operating in Pinellas County for more than a decade. Allegiant has grown aggressively since its inception in 2004, when the company had just one aircraft and two routes out of Las Vegas. Now Allegiant has 85 planes that fly to more than 105 cities across the country on over 300 routes.
The Federal Aviation Administration does not specifically regulate airplanes' air conditioning systems, the agency said, instead leaving it to the air carriers to keep passengers comfortable. Airplanes are typically cooled at the gate by external air conditioning units and air from the jet bridge, which passengers walk through to get to the plane. Allegiant's June 22 flight out of St. Petersburg, Grey said, employed both.
But comfort can also be relative. And when outside temperatures are hot and the plane is full of people, the air being pumped into a plane's cabin might not feel as cool as some want, said Billy Nolen, a senior vice president of safety, security and operations for the industry trade group Airlines for America.
That's why flight attendants often ask people to close their window shades to help regulate the cabin temperature. During delays, a combination of these cooling methods can help keep a plane's temperature down.
"In virtually all of those instances you've got enough cooling air that you can keep the cabin at a comfortable temperature," Nolen said.
But Mona Aubin, spokesperson for industry group International Air Transport Association, said that the ground air conditioning and an additional engine on the plane used to power "vital aircraft systems" wouldn't be enough to combat really hot outside temperatures.
"Neither of these are particularly effective in extreme high temperatures or in large cabins, though airlines always try to assure the comfort of the passengers and crew whenever possible," Aubin said.
Passing out or other related issues because it's too hot in an airplane cabin is pretty unusual, Nolen said.
The same day as the flight to Indiana, passengers aboard a Las Vegas Allegiant flight destined for Oakland, Calif., were sweltering on a delayed plane.
"It was that uncomfortable heat where you're sitting in a car with no AC," Antwan Davis, 36, said. The Las Vegas resident was heading to a two-day gig in California's Bay Area to teach an art class in body percussion.
The flight, which was supposed to leave around 6 p.m., was delayed at the gate for just under an hour before passengers had to board another plane. The day's high had hit 113 degrees. Flight attendants did not pass out water or ice while passengers waited, Davis said. One passenger had a medical episode that looked like heat stroke or a seizure while the plane was still delayed at the gate.
"She was two rows behind us," Darrell Hemphill, who lives in Santa Cruz, Calif., said.
Allegiant's Grey said it is normal for flight attendants to not offer beverage service during a delay. If an issue delaying the flight is resolved, the beverage cart would need to be packed up and put away as soon as possible, potentially further delaying the flight. Flight attendants may do a "pour service," where they pass out cups of water, though this still takes time.
Most of the affected Allegiant flights were delayed planes still on the ground, but at least two flights had passengers who reported particularly warm cabins throughout the flight. Grey said the airline will not fly if there is a known problem with the air conditioning.
Allegiant isn't the only airline with cooling issues on the ground. With record-setting high temperatures around the country this summer, keeping planes cool on the ground can be difficult. Passengers from other airlines, such as Delta, have complained about uncomfortable cabin temperatures during delays. In late June, Dozens of flights were cancelled in Phoenix because of the heat.
Contact Malena Carollo at firstname.lastname@example.org or (727) 892-2249. Follow @malenacarollo on Twitter.