A frightening incident on Saturday with United Airlines Boeing 777, whose right engine lost parts of its engine after takeoff, prompted several airlines that operate older models of the widebody to grouded their aircraft. In a statement, the US manufacturer recommended suspending operations of 128 jets, 69 of which were active.
On Saturday, flight UA328 had taken off from Denver to Honolulu when the right engine suffered a severe crash, caught fire and started to vibrate. Despite the impressive image, the crew managed to make an emergency landing safely. None of the 241 occupants or people on the ground were injured.
All grounded aircraft are equipped with the PW4000 turbofan, manufactured by Pratt & Whitney. United’s aircraft, registration N772UA, is one of the oldest ‘triple-seven’, having been delivered in September 1995.
In December, another 777-200 of Japan Air Lines suffered a similar incident, which prompted the Japan Civil Aviation Bureau to ban flights with the Boeing jet even before the positioning of the FAA, the US federal civil aviation agency.
“Boeing is actively monitoring recent events related to United Airlines Flight 328. While the NTSB investigation is ongoing, we recommended suspending operations of the 69 in-service and 59 in-storage 777s powered by Pratt & Whitney 4000-112 engines until the FAA identifies the appropriate inspection protocol,” said the planemaker on Sunday.
Boeing also commented that “supports the decision yesterday by the Japan Civil Aviation Bureau, and the FAA’s action today to suspend operations of 777 aircraft powered by Pratt & Whitney 4000-112 engines. We are working with these regulators as they take actions while these planes are on the ground and further inspections are conducted by Pratt & Whitney.”
Old engine
The aircraft involved in grounding are among the oldest manufactured. With more than 1,600 units delivered in 26 years, the 777 aircraft can be equipped with three types of engines, the GE90, Trent 800 or the PW4000, but the Pratt & Whitney turbofan is the least popular of them, being present in 174 airplanes produced between 1995 and 2013.
According to the NTSB (National Transportation Safety Board), “the initial examination of the airplane indicated most of the damage was confined to the number 2 engine; the airplane sustained minor damage. The initial examination of the Pratt & Whitney PW4077 engine revealed that the inlet and cowling separated from the engine, two fan blades were fractured, one fan blade was fractured near the root, an adjacent fan blade was fractured about mid-span, a portion of one blade was imbedded in the containment ring and the remainder of the fan blades exhibited damage to the tips and leading edges.”
Pratt & Whitney said that “is actively coordinating with operators and regulators to support the revised inspection interval of the Pratt & Whitney PW4000 engines that power Boeing 777 aircraft”.
Currently, only five airlines have 777 jets with the PW4000 engine, United Airlines, JAL, All Nippon Airways (ANA), Asiana and Korean Air.
