The handling pilot and observer arrived at the aircraft at 1040hrs. The APU was started at 1050hrs. The Commander arrived at the aircraft at 1100hrs. At different times, each of the two crew members was seen to carry out an independent external inspection of the aircraft. During the morning, various witnesses had seen frost/ice on the wing surfaces of N90AG. Other aircraft had been de-iced during the morning, with associated reports of severe to moderate ice accumulation. The following are transcripts from the CVR: