mag drops ??
Port outer, port inner, followed by starboard inner, starboard outer. Once all the checks were done – the mag drops and oil pressures and so on – Fraser asked control for permission to taxi. He glanced at Teddy as if he needed his approval more than he needed the control tower’s and Teddy gave him a thumbs up.
I would like to know what does " mag drops" mean ? does "mag" refer to "magnetic" ??Thanks.