Singapore Airlines flight SQ321 from London Heathrow to Singapore Singapore Airlines flight SQ321, operating from London Heathrow to Singapore, declared an emergency and diverted approximately one hour and thirty minutes from its destination. The Boeing 777-300ER, registered as 9V-SWM, departed from London Heathrow on Monday at 22:37 BST. Severe Turbulence and Emergency Declaration According to our data, Singapore flight SQ321 experienced a sudden drop of approximately 6000 feet, as the graphic below shows: FL39 (39.000 ft) @ 2024-05-21 08:05:28 UTC to FL31 (31.000 ft) @ 2024-05-21 08:10:21 UTC. Flight tracking data suggests that #SQ321 had a steep drop of 6,000 feet within 4 minutes from 37,000 ft altitude (see lines 4.06 am to 4.11am) before stabilizing to 31,000 ft, leading to its emergency landing at BKK.