- United Airlines flight 328 safely landed after experiencing an engine failure over Denver over the weekend.
- Even if the engine malfunction happened over the water while he was on his way to Hawaii, the plane could probably land safely.
- Wide-body planes like the Boeing 777 are estimated to fly more than five hours on a single engine.
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A United Airlines flight from Denver to Honolulu successfully performed a safe landing on Saturday after suffering a fire failure on the engine shortly after takeoff.
Although the wreckage was dumped in a Denver suburb, the plane was able to quickly turn around and land back at Denver International Airport, with no injuries or lives lost.
The entire ordeal lasted less than 30 minutes after the breakdown happened a few kilometers from the large international airport. But as this aircraft moved toward Hawaii, there was a possibility that the aircraft might have lost its engine as it flew high over the Pacific Ocean – with the nearest airport potentially hundreds of miles away.
This is a scenario that regulators have been afraid of since the start of the jet. The theory that led was that more engines in the plane would help the planes reach the nearest airport in the event of a breakdown. Three- and four-engine planes such as the Boeing 747, Douglas DC-8 and Lockheed L-1011, among other things, ruled the ocean sky for that very reason.
The regulators eventually created standards for the operational performance of extended-range twin-engine engines, or ETOPS, where twin-engine aircraft could cross oceans. The aircraft had to stay at a certain time of flight from the nearest appropriate airport in case an emergency landing was required.
The Boeing 777-200, the plane in question over the weekend incident, can fly for five hours with just one engine thanks to a 330-minute ETOPS certification. That’s roughly the flight time from Los Angeles to Honolulu.
When flying over the Atlantic between North America and Europe, passing airports typically include Keflavik Airport in Iceland, Gander International Airport in Canada, and Narsarsuaq Airport in Greenland. But flights to Hawaii from the U.S. mainland often do not have medium-sized airports along the route, and pilots have two options: return to the mainland or continue to Hawaii.
“The decisions the crew would have to make would be based on the location of the aircraft,” Henry Harteveldt, founder of travel research company Atmosphere Research Group, told Insider. “Did he arrive halfway between the mainland and Hawaii? If he didn’t, chances are he would return to the mainland and land at the nearest airport that could accommodate 777.”
Overseas flights are sent subject to ETOPS requirements to ensure that the diverting airport is always at hand, assuming that engine failure or shutdown does not lead to other aircraft problems.
San Francisco International, Los Angeles International and San Diego International, to name just a few, are possible diversion airports if the aircraft has to return to the mainland. But if they cross halfway, the pilots might decide to head for Hawaii and could even determine that they can land at the airport to which they are destined.
For example, a plane flying from Denver to Honolulu would not work unless that plane could fly to a single-engine diversion airport at any stage of the flight, either over the Colorado suburbs or midway between the mainland and Hawaii.
A new generation of aircraft based on ETOPS
Fears of a surface-to-engine jet engine failure have prevented the segment from developing for decades. True innovations with twin-engine aircraft only emerged when aircraft regulators introduced ETOPS in the 1980s and manufacturers began building larger twin-engine jets such as the Boeing 777, Airbus A350 XWB and Boeing 787 Dreamliner.
These planes are now replacing more expensive four-engine planes like the Boeing 747 and Airbus A380, with new types like the Boeing 777X currently under construction. The twin-engine aircraft now operate the longest flights in the world, including the latest New York City-Singapore route operated by the Airbus A350-900ULR.
And it’s not just twin-engine wide-body aircraft that can use ETOPS because smaller aircraft like the Boeing 737 and Airbus A320 families can get certified. Flights from the U.S. mainland to Hawaii are often operated by narrow-body aircraft, and some airlines use them to fly between North America and Europe under ETOPS rules.
“Certification for the operation of these aircraft above water has been rigorous and has been going on since 1985,” Harteveldt said.
Harteveldt worked for Trans World Airlines, known as TWA, when the Boeing 767 received ETOPS certification that allowed it to fly as much as 60 minutes from the nearest alternative airport. These restrictions have been gradually increased, allowing airlines to fly more direct routes, rather than focusing on staying close to land.
United’s experience with flying above water with one engine
The shut-off surface engine is unprecedented because a United Airlines Boeing 777-200 flying from Auckland, New Zealand to Los Angeles in 2003 was forced to shut down one engine while it was over the Pacific Ocean and divert to land, according to FlightGlobal. The nearest airport in Kona, Hawaii was eventually more than three hours away, technically over 180 minutes for 777 at the time. Still, the plane was able to land safely after approximately 190 minutes from the engine shutdown.
A second United Boeing 777 flight from San Francisco to Honolulu in February 2018 was forced to shut down the engine after a Pratt & Whitney PW4000-112 engine problem, according to a report by the National Transportation Safety Board, and managed to reach the destination airport on a single engine.
Harteveldt noted, however, that the loss of the engine gondola or the lining on which the engine was located on flight 328 could negatively affect the range of the aircraft and limit the diversion of airports available for landing. It was also discovered that part of the engine actually pierced the fuselage and could have contributed to an even greater loss of aerodynamics that could have reduced its range, even more, according to Harteveldt.