Boeing is back in the headlines following a scary incident on a weekend flight in Colorado.

The latest issue -- which involves a fraction of the Boeing 777s in service -- resulted in grounding of some planes worldwide. However, the situation has major differences from the crisis over the 737 MAX, which was grounded for 20 months following two fatal crashes.

A United Airlines flight bound for Hawaii quickly returned to Denver soon after takeoff Saturday after one of the engines caught fire and began breaking apart, scattering debris over a nearby suburb.

The incident badly shook passengers, but nobody was harmed -- a huge difference from the two tragic crashes of Lion Air and Ethiopian Airlines MAX planes that together claimed 346 lives and led to the aircraft being banned from the skies for 20 months.

In the aftermath of the Denver incident, US and Japanese aviation authorities grounded the planes, and Britain banned them from its airspace.

In addition, about a half dozen carriers around the world removed from service 69 planes that had the same Pratt & Whitney PW 4000 engine involved in the incident.

Federal Aviation Administrator Steve Dickson ordered "immediate or stepped-up" inspections on 777 planes with the same engines.

Investigations are ongoing, but Dickson said the probe would center on "hollow fan blades" unique to these Pratt & Whitney engines. The vast majority of the more than 1,600 777 aircraft that have been delivered over the years do not have this type of engine.

The National Transportation Safety Board (NTSB), which also is investigating the incident, said an initial examination showed two fan blades were fractured.

Michel Merluzeau, an expert at consultancy AIR, said the problem with the engine could stem from an issue with metallurgy, fabrication, maintenance or operations.

Boeing is back in the headlines following a scary incident on a plane in Colorado that has led to airlines to ground some 777 planes Boeing is back in the headlines following a scary incident on a plane in Colorado that has led to airlines to ground some 777 planes Photo: AFP / Olivier DOULIERY

"It's not really a problem for Boeing," he said. "It's more an issue of maintenance -- how United or Pratt & Whitney is maintaining engines that have been in use for a while."

Teal Group aviation analyst Richard Aboulafia said the inspection probably would only require a matter of days, but even so airlines may not rush to return the jets to service because of the overcapacity of widebody planes and the Covid-19 pandemic.

Again the situation differs from the MAX, which had been Boeing's most popular plane. The lengthy grounding meant Boeing could not deliver aircraft during that period, badly denting revenues.

By contrast, the 777 models have been in service for years, and Pratt & Whitney has not manufactured this engine for 15 years, Aboulafia said.

Moreover, "after all those years of service, it is unlikely to be a design issue with the engine," said Aboulafia, adding that the problem seems to lie with maintenance.

While the particulars of this 777 problem do not appear to relate to Boeing's manufacturing, the issue comes at a "bad moment" for the aviation giant, Merluzeau said.

Besides the MAX debacle, Boeing's deliveries of the 787 Dreamliner were delayed after problems were unearthed during inspections. Boeing also pushed back the timing for its new 777X amid the downturn in commercial plane travel.

Boeing's operational problems in recent years dwarf those at rival Airbus, which also is struggling with reduced plane demand amid the coronavirus.

Merluzeau expects a major rethink of Boeing production systems in the coming years, with "big changes" in plane development and manufacturing.