A Bad Day for Harold the Helicopter - UK/A Bad Day for Harold - US is the fourth episode ever made in Season 6.
Percy is happily delivering the mail, but gets stuck at a broken signal and it is arranged for Harold to take the mail for him. As Harold sets off with the mail, the signal is fixed. Everyone tries to call Harold back, but he does not hear them. While is up in the air, his engine starts to rattle and then the heavy mail causes him to lose control and crash into a haystack. Percy was shocked. He puffs over to Harold and asks if he is okay. Harold tells Percy to get someone to pull him out of the haystack. Back at Tidmouth Sheds, some of the engines were teasing Harold. The helicopter thanks Percy for helping him out of the haystack and Percy says that is what friends are for.
- When Percy stops at the broken signal, the steam disappears and then reappears due to a film cut.