The FAA is investigating a Tampa-bound Southwest flight that plunged 150 feet over water

A Southwest Airlines flight bound for Tampa International Airport made a rapid descent on July 14, falling more than 1,500 feet in one minute and coming within 150 feet of the surface of Tampa Bay.

According to public flight tracking data, the incident occurred shortly after 7 p.m., when the plane was miles away from its destination. At the time, the Federal Aviation Administration flight chart shows, the plane must have been more than 1,000 feet above the surface.

Instead it was flying about 15 stories high.

According to the weather station at Tampa International Airport, a Boeing 737 Max plane was grounded in stormy weather with light rain and gusts of up to 20 mph. The situation was so dire that the flight from Columbus, Ohio, was diverted to Fort Lauderdale.

According to a recording of the communication uploaded to YouTube, the air traffic control operator warned the pilots of the plane’s low altitude. At that point, the plane quickly climbed to about 1,000 feet.

Robert Katz, an experienced commercial pilot, said that when flying too close to the surface, wind shear — a rapid change in wind speed or direction — “could have dragged the plane like it was flying over Tampa Bay.”

Katz, a certified flight instructor in Texas, said the pilots did not appear to be monitoring the plane’s descent. He said pilots should be aware that they are flying at dangerous altitudes without warning from the controller.

“This shouldn’t have happened,” Katz said. “These pilots are going to do a lot of explaining.”

He said that if the situation was so bad that the plane had to be modified, that decision should have been made long before the plane reached its descent.

The FAA said in a statement that the incident is under investigation. A Tampa International Airport spokeswoman declined to comment, referring instead to Southwest.

“Southwest follows its robust safety management system and is in contact with the Federal Aviation Administration to understand and address any irregularities,” Southwest said in a statement. “Nothing is more important to Southwest than the safety of our customers and employees.”

Ben Schlapik, on his aviation blog, drew attention to the rapid descent One mile at a time, wrote on Monday that the incident was a “near disaster.” He speculated that the pilots may have mistaken the Courtney Campbell Causeway – a long, straight road – for a runway and descended with the intention of landing.

Katz said that’s possible — but only if the pilots are too tired. Incidents like this usually happen when pilots become careless due to stress or fatigue, which can be exacerbated by bad weather, he said.

“Inside the cockpit there are plenty of indications that the plane is too low,” Katz said. “There’s a lot of checks and balances to get somebody’s attention, you know, get up, do something.”

The Southwest jet flew at an unusually low altitude when the plane was miles from the airport, following a similar incident in Oklahoma City last month.

In April, a Southwest plane sank off the coast of Hawaii, coming within 400 feet of the ocean before the plane began to climb.

The National Transportation Safety Board is investigating a Southwest jet that performed an unusual “Dutch roll” and was found to have damage to its tail after a flight from Phoenix to Oakland, California. Investigators say the plane was parked outside during a severe storm.

Times Staff Writers Lesley Cosme Torres and Shauna Muckle contributed to this report.