time
1500 NM with gear down must take considerable longer than 3h 30 min. im not familiar exactly in what speed the 747 can fly with gear down but I guess its not far from 250kts I guess ? (like on types I know). I also would think that the max alt is limited ? maybe to FL250 ? easy math then would be much longer flt time. Or am I wrong ?
Regards
Wings1011