"Pit of Peril" is one of several early "Thunderbirds" episodes that was originally 25 minutes long but had its running time doubled after Lew Grade, APF's chairman, was greatly impressed by the 25-minute pilot version of "Trapped in the Sky" and ordered that all episodes be extended to fill a one-hour timeslot.For "Pit of Peril", this involved adding new supporting elements in the form of the relief helijet and its crew (Lieutenant Mead, Sergeant Reynolds and Pilot Charlie) as well as a subplot in which the army personnel investigate the accident zone and attempt to recover the Sidewinder using their own equipment.