SYDNEY- A United Airlines (UA) flight from Sydney (SYD) to San Francisco (SFO) experienced two unexpected diversions after a mid-air medical emergency, delaying its arrival by over 15 hours.
Flight UA870, operated by a Boeing 777, first diverted to Apia, Samoa (APW), and later rerouted to Honolulu (HNL) for a crew change before finally reaching San Francisco late Tuesday night.
Photo: By tjdarmstadt – IMG_0388.jpg, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=61530146United Flight Diverts Twice
United Airlines flight UA870 departed Sydney (SYD) on May 11, 2025, at approximately 11:35 a.m. local time, bound for San Francisco (SFO) across the Pacific Ocean.
About halfway through the 13-hour journey, a medical emergency on board prompted the flight crew to divert to Faleolo International Airport in Apia, Samoa (APW), to seek urgent care for the affected passenger.
Once safely on the ground in Apia, the passenger was transferred to a local hospital. However, the unexpected stop created a new operational challenge.
Due to the length of the diversion and strict aviation work-hour regulations, the original flight crew was no longer legally permitted to complete the flight to San Francisco — a situation known as “timing out.”
Photo: By BriYYZ from Toronto, Canada – United Airlines Boeing 777-200 N778UA, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=25906132Strategic 2nd Diversion to Honolulu
United Airlines does not operate regular service to Samoa, leaving limited logistical options. Rather than leave passengers stranded, the airline calculated that the crew had sufficient legal working hours remaining to reach Honolulu (HNL), roughly six hours away.
After coordinating with operations teams, flight UA870 departed Apia in the early hours of Tuesday and landed in Honolulu, where a replacement crew took over. The aircraft finally arrived at San Francisco International Airport (SFO) at 10:30 p.m. Tuesday — more than 15 hours later than originally scheduled.
This type of two-stage diversion is becoming a practical solution for airlines managing extended disruptions caused by in-flight emergencies and flight time regulations, reported PYOK.
The flight was operated by a 25.9-year-old Boeing 777-200ER registered as N79011.
Photo: Clément AlloingSimilar Diversion
Airlines globally must adhere to strict Flight Time Limitations (FTL) regulations that cap the number of hours pilots and cabin crew can work in a single duty period.
These regulations are enforced to ensure safety, but can complicate responses to mid-flight medical issues, especially on ultra-long-haul routes.
In cases where diversions are unavoidable, airlines must quickly assess available airports, crew duty hours, and potential contingencies. United’s solution — rerouting to a hub where crew replacements are available — reflects an increasingly adopted industry practice to complete disrupted flights efficiently.
Other airlines, such as British Airways (BA), have also executed similar diversions. In a recent example, a British Airways flight from Nassau (NAS) to London Heathrow (LHR) diverted to Gander (YQX) and then Keflavík (KEF), where a separate aircraft with fresh crew completed the journey.
To reduce unnecessary diversions, many international carriers partner with ground-based medical support services. These systems allow cabin crew to consult with physicians via satellite phone during emergencies. These doctors advise whether a diversion is medically necessary based on symptoms and onboard care capabilities.
Despite expert advice, the final decision always rests with the flight’s captain. Pilots are trained to weigh multiple safety, medical, and logistical factors before making the call to divert.
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Two United Airlines Boeing 777 Operated Flight Makes Emergency Landing
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