The engines on elderly Boeing 777 airliners are blowing up with worrisome frequency.
In 2018, the No. 11 fan blade on the right engine of a United Airlines 777 broke as the plane approached its destination, Honolulu. Its pieces, traveling at high speed, caused a cascade of failures within the engine’s intricate machinery such that within less than a second, the engine’s cover had blown off, leaving the naked core wobbling as it spun. Flying debris caused two punctures in the fuselage but the plane was able to land safely under the power of its remaining engine.
Last December, a Japan Airlines 777 suffered a similar engine failure after the No. 16 fan blade of its No. 1 engine broke en route between Naha, Japan, and Tokyo. That flight, too, landed safely.
And then on Saturday, another United Airlines 777 suffered an uncontained engine failure as it climbed out of Denver en route to Honolulu. Witnesses on the ground reported hearing an explosion before debris rained down on the town of Broomfield, Colorado. The pilot declared mayday and returned to Denver without further incident.
In all three cases, the aircraft were among the oldest in the worldwide 777 fleet, having been delivered in the first two years after the model was introduced in 1995. While the Pratt & Whitney PW-4000 engines in each case were likely not original to each plane — engines are regularly removed from planes for routine maintenance, then installed on different aircraft — the engines are generally of similar vintage to the aircraft on which they fly. In the 2018 incident, the engine that failed had been built in 1996 and had accumulated 77,593 hours flight hours and 13,921 cycles (combined takeoffs and landings). The blade that failed in the 2020 incident had experienced 43,060 flight hours and 33,518 cycles.
Patterns in aircraft accidents can be a sign of trouble. While one-off failures might be attributable to a freak coincidence or just bad luck, patterns suggest that a previously unsuspected danger is lurking. Continue reading New York: Why Do Boeing 777 Engines Keep Exploding?