A Delta Air Lines flight from Salt Lake City to Washington made an emergency landing in Denver on Thursday after the plane’s windshield shattered midair.
After the crew of Delta Flight 760 “declared an emergency due to a cracked windshield,” the flight landed safely at Denver International Airport around 11:15 p.m., the Federal Aviation Administration said in a statement. What caused the windshield to crack is still undetermined, but the F.A.A. said it would conduct an investigation.
Melissa B. Long, a Delta spokesperson, confirmed that the plane, a Boeing 757, had a “maintenance issue mid-flight,” but did not offer information about when the windshield started to crack or why.
“Out of an abundance of caution, the flight crew diverted into Denver and the plane landed routinely,” Ms. Long said in a statement on Saturday. “Our team worked quickly to accommodate customers on a new plane, and we sincerely apologize for the delay and inconvenience to their travel plans.”
A photo of a cockpit posted on Twitter shows a windshield lined with multiple fractures and cracks but still held in its frame.
According to KUTV, a CBS affiliate in Salt Lake City, one of the 198 passengers aboard the flight said that about 90 minutes after takeoff, an announcement was made that the plane would be landing in Denver.
“They came on the loudspeaker saying that the windshield had shattered, and we were diverting to Denver in about 10 minutes,” the passenger, Rachel Wright, told KUTV. “I was sure I had misheard them, but I hadn’t.”
She said that the crew asked the passengers to remain calm while they rerouted.
“They kept coming on saying for everyone to stay calm, to be calm, and we were calm, so being told to stay calm while we were calm made us feel a little panicky,” Ms. Wright told KUTV.
Cockpit windshields usually contain two panes of thick glass with a plastic layer in between for heating as well as for anti-ice and anti-fog systems, John Cox, a former US Airways captain, wrote in a USA Today column about aircraft in 2019. He said that in the event of shattering or rupturing, either glass pane is capable of holding full pressure if the other is lost or broken.
He added that heating problems are usually the cause when the outermost pane of a cockpit windshield cracks, forming spiderweb-like patterns on the glass. According to Mr. Cox, windshields are more likely to crack while a plane is climbing than during other phases of a flight, but he has heard of several pilots who have experienced cracked windshields at cruising altitude.
Airplanes are designed to remain safe if a windshield or cabin window cracks, he said. “While this does happen occasionally,” Mr. Cox wrote in USA Today, “it is infrequent.” Most pilots will descend to reduce the pressure and plan on a diversion if necessary.