Have just completed a SQ176 SIN-HAN and SQ175 HAN-SIN round trip and noted the unusual flight routing, both there and on the return flight.
Hanoi is just about due north north of Singapore so I expected us to fly directly across the Gulf of Thailand, Thailand, Cambodia, Laos and then enter Vietnamese airspace to land at Hanoi.
However, about half way across the Gulf we turned north-east and tracked to Ho Chi Minh City. Overhead HCMC SQ176 turned due east! About 5 minutes later, directly over a largish dam, we headed north-east for another few minutes then directly north to Da Nang. Overhead Da Nang the B777 turned north-west to then track directly to Hanoi.
Three days later my return flight followed the reciprocal route precisely!
Anyone know the reason for this routing which probably adds 30 minutes to the 3.5 hour flight? Is it a requirement of the Vietnamese authorities? Or are there airpsace issues with respect to Laos and/or Cambodia? And if so do these restrictions apply just to Singapore Airlines or to all airlines?