Engine that endangered United flight has troubled history

Corky Siemaszko
·4 min read

The Pratt & Whitney airplane engine that burst into flames and forced a United Airlines pilot to make an emergency landing shortly after taking off from Denver had similar blowouts on at least two other flights, experts said Monday.

Three years ago, a fan blade broke on one of the PW4000 engines powering another United Airlines Boeing 777-200 plane, this time while flying over the Pacific Ocean on a San Francisco to Honolulu flight.

And in December, two fan blades in the same kind of engine broke on a Japan Airlines Boeing 777-200 that was flying from Naha to Tokyo.

Just as in Denver, the pilots on both these flights were able to safely land their planes and nobody was hurt.

“This isn’t the first time this happened,” aviation expert Greg Feith said on NBC's “Today” show, referring to the PW4000 engine malfunction.

But after Saturday’s fiery episode in the skies over Colorado, images of which went viral on social media, Boeing has grounded all of its older model 777-200 airplanes worldwide while federal investigators inspect the PW4000 engines on the planes, which are used only by United Airlines in the U.S. and by airlines in Japan and South Korea.

In particular, Federal Aviation Administration administrator Steve Dickson said inspections are being “stepped up for the hollow fan blades that are unique to this model of engine, used solely on Boeing 777 airplanes.”

Former National Transportation Safety Board chairman Jim Hall said the faulty blades are only on "the first generation" of the PW4000 engines.

“I suspect the reason the planes are all being taken out is because they (the FAA and Pratt&Whitney) don’t have any inspection process in place and they’re embarrassed,” Hall told NBC News. “For the last decade, the FAA has been responding to the economic interests of the aviation industry, which has taken precedence over safety.”

Pratt & Whitney, which is owned by Raytheon, insisted it was cooperating with federal investigators.

“United Airlines Flight 328 is currently under NTSB investigation and Pratt & Whitney has dispatched a team to work with investigators," the company said in a statement. “Pratt & Whitney is actively coordinating with operators and regulators to support the revised inspection interval of the Pratt & Whitney PW4000 engines that power Boeing 777 aircraft.”

But an NTSB investigation of the Feb. 13, 2018, malfunction of a Pratt & Whitney engine on the Honolulu-bound United flight faulted the company for not doing more stringent inspections.

“The lack of training resulted in the inspector making an incorrect evaluation of an indication that resulted in a blade with a crack being returned to service where it eventually fractured,” the report stated.

Boeing said it, too, was cooperating with the feds. “We believe that every investigation is an opportunity to learn how the industry can continue to make air travel safer for everyone,” the company said in a statement.

Feith said there are safeguards built into the Boeing 777-200s to prevent them from crashing after this kind of engine malfunction.

“The FAA requires that the manufacturer of a two-engine plane like this certify it so it can fly on one engine, which it did,” Feith said.

Still, the fact that the flames took so long to extinguish raises troubling new questions about the safety of the PW4000 engine, he said.

“If this aircraft had been over the ocean for one or two hours, the bigger concern is that there is a fire suppression system on the engine and the fire continued to burn,” he said.

United Flight 328, bound for Honolulu with 231 people aboard, reported trouble Saturday shortly after taking off from Denver.

Video from a passenger showed one of the plane’s engines aflame and falling apart before debris began raining down on the Denver suburbs as the pilot reported “mayday” to the control tower and began turning the jet around.

A similar scenario played out Saturday on a different Boeing jet in Holland. The pilot of New York-bound Longtail Aviation jet, a 747-400 cargo plane powered by smaller versions of the PW4000 motors, was informed by air traffic control that one of the engines was on fire shortly after taking off Saturday from Maastricht Airport.

Witnesses reported hearing at least two blasts and the plane began shedding engine parts, piece of which injured a woman on the ground, airport spokeswoman Hella Hendriks told Reuters.

Dutch authorities are now investigating.