DTT HGV Coupling and Uncoupling Trailers 3

Question 1

The yellow (service) airline on a truck-trailer combination is used for:

Accepted Answer

Controlling the service (foot) brakes on the trailer

Answer

Emergency braking only, independent of the foot brake

Answer

Supplying air to the trailer's air suspension

Answer

Powering the trailer's electrical braking system

Question 2

If you discover a cracked or damaged kingpin during a pre-coupling inspection, you should:

Accepted Answer

Not couple the trailer until the kingpin has been repaired or replaced

Answer

Couple carefully and report the damage at the depot

Answer

Reinforce the kingpin temporarily with a heavy-duty chain

Answer

Only use the trailer for short local journeys until repaired

Question 3

What is the risk if the fifth wheel height is too high when coupling?

Accepted Answer

The kingpin may not lock fully into the fifth wheel jaws

Answer

The trailer lights may not make electrical contact

Answer

The airline connections may be forced apart

Answer

The landing legs may bend or buckle under pressure

Question 4

After uncoupling a trailer, before driving the tractor unit away, you should check:

Accepted Answer

That the trailer is stable and the fifth wheel jaws are clear of all obstructions

Answer

That the tachograph is recording correctly

Answer

That the fuel level in the tractor is adequate for the return journey

Answer

That all cab mirrors are correctly adjusted for solo driving

Question 5

What does 'bobtail' mean in the context of truck driving?

Accepted Answer

Driving a tractor unit without a trailer attached

Answer

A trailer with defective rear lighting

Answer

A type of fifth wheel coupling mechanism

Answer

A short-distance journey under 50 km

Question 6

Why is it essential to ensure the landing legs are fully lowered and secure before releasing the fifth wheel during uncoupling?

Accepted Answer

To support the trailer's weight and prevent the nose from crashing to the ground

Answer

To prevent the trailer from drifting sideways on a slope

Answer

To keep the trailer at the correct loading dock height

Answer

To allow the airlines to be disconnected without pressure

Question 7

Which of the following is a legal requirement before a truck and trailer combination departs on an Irish public road?

Accepted Answer

The coupling must be inspected and confirmed secure by the driver

Answer

All coupling components must be painted in high-visibility yellow

Answer

The driver must carry spare kingpins and fifth wheel jaws

Answer

The trailer must be loaded to at least 50% of its maximum capacity