The fuel required to fly from Nyala to khartoum is 8,000 lbs plus 45 min holding and alternate fuel which is about 12,000 lbs. B737-200 burn 6,000 lbs per hour and ground speed is about 430 knots in most cases. the aircraft hijacked immediately after takeoff and the time to fly to Kufra is about 0230 from Nyala and the endurance of 737 was about 0330, so it's easy to rich there with extra one hour but the 737 consumed about 45 min when it was flying direct position SML in Egypt and finally changed their destination to kufra.
Kufra tower refused to issue landing clearance to Sun Air B737 but the PIC declare emergency due to short of fuel and they landed safely