Speed can be found by dividing distance by time, so as the pilot traveled 441 km in 31.5 mins, your speed would be 441/31.5=14 km/min. The best thing to convert this to would be meters per second (m/s), which you can do by multiplying by 50/3, which gives you a speed of (14*50)/3=700/3=233.333 m/s.