It’s a full plane so they don’t want to get stuck.
Was not as simple as that.
Factors:
1)Weather: Inclement weather and approaching storm. SQ usually use 06 but the storm persuaded them to use 5L (I think longer runway and has Cat II ILS instead of Cat I ILS)
2)Environment: night environment
3)Airport: Failure of airport to consider possibility of wrong runway use and poor signage about 5R closed runway
4)Airport: Failure to maintain signage, markings and lighting to international standards. Lights actually led the pilots onto 5R and gave the impression of an open runway (though the pilots were mistaken)
5)Airport: Allowing use of part of 5R as a taxiway to 5L
4)ATC: Issue of takeoff clearance while the aircraft was about to turn onto 5R (on the way to 5L)
5)Pilot: Only one pilot was focused outside of aircraft. The rest were focused inside the coughpit.
6)Pilot: Unfamiliar with 05L/05R. Usually use 06, but weather persuaded them to use the longer 5L
7)Pilot: Get away-itis
7)Pilot: lack of training in low visibility taxiing
8)Airline: inadequate takeoff procedures.
As usual a lot of holes needed to align (swiss cheese)