5.37 A transport aircraft with twin turbofan engines each generating 3,000 lbf of thrust has the following characteristics: Wro 16,300 lbf, W,= 4,000 lbf, S=312 ft, K=0.025, CD, = 0.038, C = 1.2 Lmax Calculate the absolute ceiling if it takes 30 min to climb that altitude with an average fuel consumption of 1800 lbf/h.