A US Airways flight from Edmonton has been forced to make an emergency landing in Salt Lake City after the plane's windshield cracked mid-flight.

The plane left from the Edmonton International Airport at 7 a.m. and was bound for Phoenix, Ariz.

CTV News reporters Erin Isfeld and Dez Melenka were on board the aircraft and report the pilot came on the intercom about 90 minutes into the flight to inform passengers the windshield had cracked.

"All of a sudden you could feel the pilot put the plane into sort of a lower gear," Isfeld said.

An airline official tells CTV News the pilot started a rapid descent as soon as the windshield cracked, dropping the plane down to 10,000 feet.

Despite the emergency, Isfeld said the passengers remained calm throughout the entire ordeal. The plane was diverted to Salt Lake City, Utah, and landed safely a short time ago.

There was no loss of pressure in the cabin during the shortened flight.

An airline official confirmed the safety glass part of the windshield remained intact, adding that without the reinforced glass, the aircraft would have lost pressure and the outcome might not have been the same.

As passengers were deboarding the plane, Isfeld said they could see the damage to the front window.

"The entire plane's front windshield was cracked, I don't know how the pilot could see out of it, that's how bad it was," she said.

There were about 76 passengers on the plane at the time.

There is no word on what caused the windshield to crack.

The cause of the broken windshield is under FAA investigation.