• United Airlines Flight 870 took 28 hours to reach San Francisco.
• After leaving Sydney, it diverted to Samoa, then stopped again in Hawaii.
• Airlines sometimes choose to stop again after a diversion, as it may be easier to find replacement staff.

United Airlines passengers spent 28 hours traveling across the Pacific Ocean as their flight made two unscheduled landings.

Flight 870, from Sydney to San Francisco, typically takes around 13 hours.

The Boeing 777 departed Australia on Sunday at around 11:30 a.m. local time, an hour later than scheduled, according to data from Flightradar24.

If passengers were irritated by the delayed takeoff, they had a lot more awaiting them.

Four-and-a-half hours into the journey, the plane turned southeast toward the Pacific island nation of Samoa, per Flightradar24. It landed in the capital, Apia, two hours later.

An airline spokesperson told BI the flight "diverted to Apia to address a potential medical concern with a customer."

The plane spent more than three hours on the ground in Samoa before taking off again, but it only traveled as far as Hawaii.

The six-hour flight to Honolulu also saw passengers cross the International Date Line. So when it landed in the state capital around 7:30 a.m. local time on Sunday, this was technically earlier than when the passengers left Australia.

However, they then had to wait another seven hours before they could depart again for the final leg of their journey to San Francisco.

Flight 870 ultimately concluded there at around 10:30 p.m. PT, some 15 hours later than expected.

The United spokesperson said the flight "made an additional stop in Honolulu to swap crew members."

It looks like this was because the emergency meant the crew would have exceeded their maximum working hours.

As the carrier doesn't typically fly to Samoa, it wouldn't have been able to find a new flight crew there without disrupting other journeys. By contrast, United serves several cities from Honolulu.

This tactic for minimising disruption is not uncommon.

Last month, a British Airways flight from the Bahamas to London also made two stops after a medical emergency.

It first diverted to Canada's remote Gander International Airport, before stopping again in Iceland.

British Airways arranged for the second stop because it was easier to send a replacement crew there than to Canada.

• There was a medical emergency on board a British Airways flight from the Bahamas to London.
• The flight was diverted to Canada but soon carried on towards its destination.
• However, it diverted again to Iceland to pick up a new crew due to the original crew timing out.

More than 200 British Airways passengers were delayed by 11 hours after unexpectedly stopping twice on their way home from the Caribbean.

Tuesday's Flight 252 left Nassau in the Bahamas around 10:30 p.m. local time, bound for London.

Four hours later, the Boeing 777 was flying over the North Atlantic when it abruptly turned west toward Canada, according to data from Flightradar24.

It diverted to Gander International Airport in Newfoundland and Labrador, which is usually only home to small regional planes.

A source familiar with the situation told Business Insider that the plane had to divert due to a medical emergency.

After the customer deplaned, the flight took off again less than three hours later, per Flightradar24 data.

However, while the flight was again listed as heading to London Heathrow Airport, it actually flew to Iceland first.

After a roughly three-hour flight, the 28-year-old Boeing 777 landed at Keflavik Airport in the capital, Reykjavík.

It then didn't take off again for more than six hours.

BI understands that due to the first diversion, the flight crew was set to exceed their maximum amount of working hours. So British Airways got creative and arranged for the flight to stop in Iceland — where it was easier to send a replacement crew than it would have been to Canada.

From there, it was another two hours and 20 minutes to the final destination.

The Boeing 777 landed in London around 10:30 p.m. local time on Wednesday. It was initially scheduled to arrive at 11:40 a.m.

It appears that the original pilots and flight attendants had to stay in Iceland overnight before returning to London.

In medical emergencies such as this, pilots typically have no choice but to land at the nearest airport. That's unlike some technical problems when they can return to a hub airport where it's easier to reroute passengers and crew.

Diverting twice is certainly unusual, but it looks like it ultimately saved the passengers time.

Last May, an Air France flight from Paris to Seattle diverted to Canada's Nunavut territory — and had to wait 11 hours for a replacement plane to pick passengers up.

Earlier this month, Virgin Atlantic passengers were delayed 40 hours after a medical emergency forced them to divert to a small airport in Turkey — where the plane then had to undergo technical inspections.

• Two passengers engaged in "intimate acts" on a Swiss International flight from Bangkok to Zurich.
• A flight crew member took a video of the incident from a monitor in the cockpit.
• Swiss said the crew should have intervened immediately, and that it was investigating.

Airline crew members are under investigation after a video of two passengers on a Swiss International Air Lines flight emerged on social media.

The incident took place last Friday on a flight from Bangkok and Zurich, an airline spokesperson told Business Insider.

The spokesperson said two passengers were in the front galley of the Boeing 777 near the flight deck, where a camera is located that lets pilots carry out checks before opening the cockpit door.

From a screen on the flight deck, the couple were "observed engaging in intimate acts" while a crew member recorded them on a phone.

Footage of the couple then began circulating on WhatsApp and was obtained by the Swiss newspaper 20 Minuten, which first reported the story.

The airline said it expected the crew to intervene immediately and found it "intolerable" that the passengers were filmed and commented on instead. Disciplinary action against the crew members was being considered.

"Filming people without their clear consent and sharing these recordings is contrary to our guidelines and values," the Swiss spokesperson said.

"The behavior of the passengers in question was inappropriate — therefore, our employees should have acted in line with our protocols and intervened immediately," they added. "Why the crew did not act accordingly is the subject of the ongoing investigation."

Among other things, the airline plans to increase employee education and training on such topics to help avoid similar incidents in the future.

• A KLM Boeing 777 flying from the Netherlands to South America turned around over the Atlantic Ocean.
• The passengers were traveling to the small nation of Suriname but ended up back in Amsterdam.
• Diverting back to an airline's hub can make it simpler to reroute passengers or make repairs.

A KLM plane U-turned over the Atlantic Ocean, leaving passengers with a four-hour flight to nowhere.

The Boeing 777 left Amsterdam for Paramaribo, the capital of the small South American nation of Suriname, on Sunday.

Data from Flightradar24 shows the flight departed on time. But two hours into the journey and about 900 nautical miles from Amsterdam, the Boeing 777 turned around over the ocean and headed back.

It landed back at Amsterdam's Schiphol Airport about four hours after takeoff. The flight to Suriname, which was once a Dutch colony and still uses Dutch as an official language, typically takes just under nine hours.

The Aviation Herald, which first reported the incident, said the pilots told air traffic control the plane had a small leak, but it wasn't clear what type.

A KLM spokesperson told Business Insider there was a "technical malfunction," adding, "As a precaution, the aircraft returned after two hours of flying."

Passengers flew on a replacement aircraft about eight hours after the scheduled departure time.

The 777 was back in service the following day, according to Flightradar24.

It's not the first time passengers have been left with a flight to nowhere in recent weeks.

Last month, an American Airlines flight encountered turbulence on the way from Brazil to Miami. It turned back to São Paulo, and one passenger was taken to hospital.

In late October, a British Airways Boeing 777 experienced a problem over the Atlantic. It turned back to London and landed there nine hours after takeoff.

For carriers flying over the Atlantic, a flight to nowhere is often the best decision when something goes wrong. It's typically simpler for airlines to reroute passengers and fix planes back at their hub airports.

But sometimes diversions to non-hub airports are unavoidable. In May, for instance, an Air France jet made an urgent landing in Canada's far north, causing a different flight to be canceled to rescue the passengers.