Engine Anti-Icing

The pilot apparently decided not to return to the gate for reapplication of deicing, fearing that the flight's departure would be even further delayed. More snow and ice accumulated on the wings during that period, and the crew was aware of that fact when they decided to make the takeoff.
The crew did not activate the engine anti-ice system. The copilot announced and the pilot confirmed that the plane's own engine anti-icing system was turned off.
First Officer Pettit noted several times to Captain Wheaton that the instrument panel readings he was seeing did not seem to reflect reality (he was referring to the fact that the plane did not appear to have developed as much power as it needed for takeoff, despite the instruments indicating otherwise). The captain dismissed these concerns and let the takeoff proceed. Investigators later determined that there was plenty of time and space on the runway for Wheaton to have aborted the takeoff, and criticized his refusal to listen to his first officer, who was correct that the instrument panel readings were wrong. The pilot was told not to delay because another aircraft was 2.5 miles out (4 km) on final
Contributing to the accident were the prolonged ground delay between deicing and the receipt of ATC takeoff clearance during which the airplane was exposed to continual precipitation, the known inherent pitch up characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice, and the limited experience of the flight crew in jet transport winter