The Triple 7 & Triple Coincidences

Boeing 777-200 S/Nos 26930 on take off.

As United Airlines 328 climbed out of Denver on February 20, en route to Hawaii, the Nos 2 engine suffered a double fan blade failure. Remarkable footage filmed by a passenger is a testament to the fact that the engine containment worked to prevent a catastrophic event. 

I've seen no reports to suggest any debris entered the cabin or harmed the aircraft's systems beyond the engine. Parts did fall off, although fortunately, no one sustained injuries. The Boeing 777 made a safe landing back at Denver.

Attention now focuses on the Pratt & Whitney PW4000 engine, with metal fatigue in the fan blades as the likely culprit. As a precaution, all 51 operational Boeing 777s with Pratt & Whitney engines are grounded out of a global fleet of 125 such planes.

““The engine containment worked to prevent a catastrophic event.””

United has by far the largest number of PW4000-equipped aircraft with a 52-strong fleet, but only 19 in service.

These groundings have had no impact on fleet capacity, given the abundance of available aircraft. Plus, since the start of Covid-19, legacy types such as the older 777 models fell out of favour with operators. The airframe involved in this incident, a Boeing 777-200 S/Nos 772UA, was the fifth 777 off the production line entering service in 1995. 

This incident has two coincidences that have gone mostly unnoticed in the mainstream media. On the same day, a variant of the PW4000 engine fitted on a 747 freighter suffered a failure as it departed from Maastricht. It shed parts that, again, suggesting a fan blade failure. Two people suffered minor injuries on the ground as the debris fell. 

Meanwhile, the passengers who returned to Denver in safety faced the option of taking another 777 to Hawaii. This replacement, S/Nos N773UA, had a very similar engine failure in 2018, around half an hour before landing at Honolulu. 

Many of these older 777s are slated for retirement soon. If it turns out that fixes or even inspections are too costly, it could well be that some of these aircraft never return to service. For example, N791UA flew to Victorville on February 19 for a much-needed repaint. It's now doubtful she will fly again. 

Boeing 777-200 S/Nos N791UA showing her age.