About a month before the engine of a United Airlines Boeing 777 burst into flames last weekend after departing Denver International Airport, a Bombardier jetliner flying from Denver to Billings, Mont., declared an emergency when one of its engines failed shortly after takeoff. That plane landed safely 20 minutes after departure.
Nearly a year earlier, the crew of an Airbus 321 jet operated by American Airlines flying from Charlotte, N.C., to Philadelphia had to abort the flight when one of its engines quit after takeoff. Again, the plane landed safely, 13 minutes after takeoff.
And then there was the Feb. 3, 2020, Spirit Airlines flight from Fort Myers, Fla., to Chicago. Minutes after takeoff, passengers heard several loud bangs and saw streaks of flames from the disabled left-hand engine of the Airbus A320. The pilots landed the aircraft safely 15 minutes into the flight.
These and other recent examples of midflight engine failures — including the latest mishap of the Boeing 777 now being investigated by the National Transportation Safety Board — demonstrate the ability of modern commercial airliners to fly for an extended period even after one engine quits.
Aviation records over the last 24 months show nearly two dozen reports of U.S.-based commercial planes aborting flights because of an engine failure or because the crew shut down an engine due to mechanical problems. In each case, the planes landed safely with one engine out of commission.
Some of the larger commercial jets fly with four engines, and they can continue with only three if needed. But even on two-engine commercial planes, each individual engine has enough thrust to continue flying the whole plane for long distances, according to aviation experts.
"The overall system is designed with the knowledge that man-made components are going to fail occasionally," said Clint Balog, an associate professor at Embry-Riddle Aeronautical University.
And pilots train regularly for such a mishap.
"We spend a lot of time in single-engine training," said R.D. Johnson, a former fighter pilot and retired American Airlines captain who now flies corporate jets. "It's pretty innate for an experienced pilot."
That was made clear during the United Airlines flight of a Boeing 777, which was en route Saturday from Denver to Honolulu with 229 passengers and 10 crew members. Just as the plane was reaching an altitude of 12,500 feet, the crew and passengers heard a loud bang and felt the plane vibrate, according to investigators. The pilots declared an emergency, turned the plane around and landed back in Denver 20 minutes later.