When uncoupling a trailer, why should you disconnect the air lines and electrical cable only after the landing gear is down and the trailer's brakes are set?

Pick an answer

1. Disconnecting them first removes the trailer's brake supply and could let it roll while still connected
2. Lines and cables must always be disconnected first so the landing gear crank handle isn't physically blocked
3. It is only a convention to keep the lines clean, not a safety step
4. The order makes no real difference as long as everything is disconnected eventually

Correct!

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