Climbing from 3500 to FL 70, Lose Contact with Tower

01YouMumbai Approach IFLY 160 Heavy, negative contact with Delhi Tower, climbing 3500 for FL 70

02ATCIFLY 160 Mumbai Approach, maintain this frequency, climb as cleared, reciprocal traffic INDAIR 430 Heavy descending to FL 70, estimate to cross at 37 DME

03YouClimbing as cleared, reciprocal traffic INDAIR 430 Heavy descending to FL 70, estimate to cross at 37 DME IFLY 160

04YouMumbai Approach IFLY 160, DME 37, INDAIR 430 has reported DME 26, request climb FL 330