Question

When coupling a tractor to a semi-trailer, in what sequence should the airlines be connected to the trailer?

a) Service line, then emergency line
b) Emergency line, then service line
c) Brake line, then fuel line
d) Fuel line, then brake line

Answer 1

The correct sequence to connect the airlines when coupling a tractor to a semi-trailer is the emergency line followed by the service line.

Step-by-step explanation:

When coupling a tractor to a semi-trailer, the sequence in which the airlines should be connected to the trailer is as follows:

1. Emergency line: The emergency line should be connected first. This line provides air to the trailer's emergency brake system.
2. Service line: The service line should be connected next. This line supplies air to the trailer's service brakes.

By connecting the emergency line first, it ensures that the emergency brakes are functional in case of an emergency.