Continuity mistake: While Gordon Tracey searches for the crashed Fireflash wreckage on the seabed, the parting in his hair keeps changing sides from shot to shot.
Continuity mistake: When Scott arrives in Ireland in Thunderbird 1, he starts to land with the landing gear down and you can see wheels on the legs, but when Thunderbird 1 touches down, the wheels have changed to skis.
Character mistake: Scott flew to Ireland to look for the missing Fireflash airliner, but when Jeff asks where Scott is, Virgil replies, "His take-off from England was delayed for some reason."
Continuity mistake: As the second Fireflash crashes, its left wheel housing pod can be seen to be split in two, yet on Fireflash's ascent to the seabed, the pod is intact.
Continuity mistake: Thunderbird 4's laser cutter is of a different scale and at a different angle in relation to the Fireflash engine pylon in close up and long shots.
Revealing mistake: Before Thunderbird 4 even starts to cut off Fireflash's engines, a line where cutting would occur can be seen on the engine pylon's leading edge.
Other mistake: Some scenes in this episode feature portraits of Jeff Tracy's sons in their civilian clothing. This is only done on "Operation Cover Up" to disguise all evidence of the International Rescue organisation when a visitor comes to Tracy Island, but there were no visitors to the island during the episode.
Continuity mistake: When Scott, Virgil and Gordon are playing snooker at Tracy Island, the balls on the snooker table change position between shots.
Continuity mistake: When Gordon returns to Thunderbird 4 after making contact with the trapped crew, the configuration of the puppet-sized Thunderbird 4 doesn't match the model seen in long-shot.
Continuity mistake: When Gordon is climbing up Fireflash to the cockpit, we see him just about to put the left rubber suckers onto the glass. However, in the close up shot, he is putting it onto the blue metal of the craft.
Other mistake: In one shot of Gordon in Thunderbird 4, the shot has been horizontally reversed.
Character mistake: After the first Fireflash crash, search and rescue tasks are unable to find the wreckage, and John in Thunderbird 5 comments that its position was way off what was reported. However, he never bothers to relay this vital information to the London airport overseeing the rescue effort, and IR never bothers to attempt a rescue of a passenger jet filled with civilians, despite showing on the second crash that they were completely capable to saving them. It's then stated that the crash had no survivors, which the viewer has to lay at IR's feet. Even if they were busy with another rescue at the time, notifying the conventional rescue effort of Fireflash's real position could have saved many lives and given the investigation more evidence to find the problem.
