In a serious turn of events, a United Airlines Boeing 777 caught fire in its Pratt & Whitney engine during a flight from Denver to Honolulu, with 231 passengers and 10 crew onboard. According to the US National Transportation Safety Board, the engine failure of the Boeing jet was a result of metal fatigue in the fan blades. The Guardian reported, “The next day, dozens of 777 planes were grounded after Boeing said those with Pratt & Whitney PW4000 engines should not be used until full inspections could be carried out.”
This mishap resulted in some serious consequences. Maastricht Airport spokeswoman, Hella Hendriks reported, “Longtail Aviation cargo plane, flight 5504, scattered small metal parts over the Dutch town of Meerssen, causing damage and injuring a woman shortly after take-off.”
“The photos indicate they were parts of engine blade, but that's being investigated," she added. "Several cars were damaged and bits hit several houses. Pieces were found across the residential neighborhood on roofs, gardens, and streets."
But, Is It Possible That Planes Can Keep Flying After an Engine Catches Fire?
The Federal Aviation Administration, for years, didn’t permit twin-engine planes to make trips over an hour. “It'll be a cold day in hell before I let twins fly long-haul over-water routes,” then-FAA administrator Lynn Helms stated when Boeing asked the FAA to make amends in 1980. Eventually, the FAA gave in, and the duration of flights were slowly extended to 120 mins and finally t0 180 mins.
Ella Atkins, an aerospace engineer at the University of Michigan remarked, “One engine has to have enough thrust to keep the airplane going, and even climbing if it needs to.” She adds that this is applicable even in worst-case scenarios when one could actually lose an engine while the aircraft takes off.
Bob Meder, the chairman of the National Association of Flight Instructors claims that pilots may experience an entire career without any situation of engine failures, despite being trained for crisis management. But when encountered with such an event, he insists, “In general, you do your memory items first for the airplane you’re flying. You’ve got an engine fire, you secure the engine and stop the flow fuel to the engine.”
However, this checklist primarily depends on steps to seclude the failing engine to minimize its deep-rooted impacts. Hence, pilots depend on information from the flight crew who usually gauge the extent to which the engine might have suffered damage. This is also because pilots cannot directly see the engine from the cockpit.
Commenting on having just one engine functioning for hours, Atkins says, “Suppose your right engine fails. You have the left engine trying to yaw you, or turn you to the right.”
Thus, with the possibility of this situation, manufacturers of twin-engine jets create the rudders and the ailerons (the hinged section near the end of the wing that controls roll) big enough and efficient enough to tackle the situation if needed.
“Even though your thrust vector is misaligned, it’s not down the center of the fuselage anymore, you can still effectively provide a counter-torque that allows the aircraft to remain straight in its velocity vector and under control”, Atkins adds.
However, Meder states that the greatest risk is when the airplane starts to roll over to its side or on its back indicating that the pilot has lost control of the aircraft. “And at that point, you’re not flying anymore”, says Meder.
Atkins further says that in a situation of an emergency landing, the planes prefer to take the shortest route available. She adds, “They currently have no way to set a trajectory that minimizes risk to people below, although there is some work being done in maps intended for low-flying drones that could take things like population or zoning into account even for large aircraft.”
After the dangerous incident last week, all the 128 flights equipped with Pratt & Whitney PW4077 engines have been grounded by the authorities. This is a way of preventing any further catastrophe related to Boeing flights.
Longtail Aviation responded saying it was, "too early to speculate as to what may have been the cause of the problem" and that it was working with Dutch, Belgian, Bermuda, and UK authorities looking into the incident.