On July 11, 2014, United Airlines flight 201, a Boeing 777-222 was four hours on the ground before the flight, with passengers waiting as some technical problem on the plane was worked out. Departure time of this flight is recorded as 18:16 but it is normally around 14:30. Then when the flight was enroute from Honolulu to Guam, the plane developed fire, haze or smoke in the cockpit. Pilots made an emergency landing at Midway Islands after Radar and Radio Comms were lost but the transponder continued working. Passenger luggage is still stuck on the tiny runway at Henderson Field Airport Midway Atoll.
The incident was unannunciated, which means that it had no alert, and the crew had to sense it (i.e. see/smell) but while underway, a smoke alarm was triggered.
None of the 335 passengers or 13 crew sustained injury.
According to flightaware, United Airlines flew in a replacement B777 which landed 5 1/2 hours later, spent an hour on the ground and brought the passengers back to Honolulu.
Ural Airlines flight U6-9785 made an emergency landing in Yekaterinburg, Russia, on December 14th.
An Aeromexico plane collided with a service truck after landing in Los Angeles, California, on May 20th.
American Airlines Flight 5627 made an emergency landing at Yeager Airport, West Virginia, on November 6th.