A56 CPCS Articulated Dump Truck Theory
Questions With Complete Solutions
SECTION I: CORE COMPULSORY QUESTIONS (Appear on Every A56 Paper)
Question 1
On articulated dump trucks, steering is achieved by actuating a hydraulic ram (or
rams) which is controlled by turning the steering wheel.
a) How does the engine supply the oil flow and
b) what happens to the steering when the engine stops?
Correct Answer:
a) The oil is supplied by the oil pump driven by the engine.
b) When the engine stops, there is no steering.
Rationale: Hydraulic steering relies entirely on engine-driven oil pressure. If the
engine stops, the pump stops, and the operator immediately loses the ability to
steer, making it a critical safety consideration when working near edges or other
plant.
Question 2
Operators should lower the body fully before driving away. Give TWO possible
consequences if this is not carried out.
Correct Answer:
1. The machine could tip over sideways, especially on uneven ground, while
the body is raised.
2. The raised body could hit overhead obstacles such as cables, bridges, or
trees.
,Rationale: A raised skip dramatically raises the centre of gravity. This can lead to a
tip-over on uneven terrain or contact with overhead hazards, which can cause
serious damage or injury.
Question 3
State the purpose of a heated body.
Correct Answer:
To keep materials warm (e.g., asphalt) or to stop frozen soil from sticking to the
body.
Rationale: A heated body prevents cold, wet, or sticky materials from adhering to
the skip, ensuring complete discharge and preventing material from building up
and affecting the machine's balance.
Question 4
What is the regarded as the most productive position for the dump truck to be in
when being loaded by a wheeled loading shovel working from a stockpile?
Correct Answer:
Positioned at a 45-degree angle to the stockpile.
Rationale: This position allows the loading shovel to approach the truck without
excessive turning, reducing cycle times and increasing productivity.
Question 5
The operator is asked to tip material into a new trench. State FIVE different
requirements that must be considered or implemented before tipping
commences.
Correct Answer:
, 1. Trench edge collapse / shoring requirements - check the trench is stable
and properly supported.
2. Check for surrounding hazards - personnel, other plant, and overhead
services.
3. Authorisation to tip / permit to work - confirm correct approval is in place.
4. Check if all personnel have cleared the trench - no one should be working
in the trench during tipping.
5. Consider using a physical stop (berm) to prevent reversing into the trench.
Rationale: Trench tipping is a high-risk operation. A trench collapse could engulf
the machine, and any personnel in the trench could be crushed by falling material.
A stop block prevents the truck from reversing over the edge.
Question 6
The operator has been asked to drive the machine onto a transporter/trailer.
a) Who is responsible for the loading operations and
b) state FOUR actions to be considered by the operator before loading
commences?
Correct Answer:
a) The transporter driver is responsible for the loading operation.
b) FOUR actions:
1. Select a level area with sufficient room to manoeuvre.
2. Check for overhead obstructions (wires, bridges).
3. Ensure the machine is clean (to prevent slippage on ramps).
4. Confirm the transporter is suitable and in good condition.
Rationale: The driver of the transporter has legal responsibility for the load and
vehicle combination. The dump truck operator must assist by ensuring their
machine is configured correctly and the loading environment is safe.
Questions With Complete Solutions
SECTION I: CORE COMPULSORY QUESTIONS (Appear on Every A56 Paper)
Question 1
On articulated dump trucks, steering is achieved by actuating a hydraulic ram (or
rams) which is controlled by turning the steering wheel.
a) How does the engine supply the oil flow and
b) what happens to the steering when the engine stops?
Correct Answer:
a) The oil is supplied by the oil pump driven by the engine.
b) When the engine stops, there is no steering.
Rationale: Hydraulic steering relies entirely on engine-driven oil pressure. If the
engine stops, the pump stops, and the operator immediately loses the ability to
steer, making it a critical safety consideration when working near edges or other
plant.
Question 2
Operators should lower the body fully before driving away. Give TWO possible
consequences if this is not carried out.
Correct Answer:
1. The machine could tip over sideways, especially on uneven ground, while
the body is raised.
2. The raised body could hit overhead obstacles such as cables, bridges, or
trees.
,Rationale: A raised skip dramatically raises the centre of gravity. This can lead to a
tip-over on uneven terrain or contact with overhead hazards, which can cause
serious damage or injury.
Question 3
State the purpose of a heated body.
Correct Answer:
To keep materials warm (e.g., asphalt) or to stop frozen soil from sticking to the
body.
Rationale: A heated body prevents cold, wet, or sticky materials from adhering to
the skip, ensuring complete discharge and preventing material from building up
and affecting the machine's balance.
Question 4
What is the regarded as the most productive position for the dump truck to be in
when being loaded by a wheeled loading shovel working from a stockpile?
Correct Answer:
Positioned at a 45-degree angle to the stockpile.
Rationale: This position allows the loading shovel to approach the truck without
excessive turning, reducing cycle times and increasing productivity.
Question 5
The operator is asked to tip material into a new trench. State FIVE different
requirements that must be considered or implemented before tipping
commences.
Correct Answer:
, 1. Trench edge collapse / shoring requirements - check the trench is stable
and properly supported.
2. Check for surrounding hazards - personnel, other plant, and overhead
services.
3. Authorisation to tip / permit to work - confirm correct approval is in place.
4. Check if all personnel have cleared the trench - no one should be working
in the trench during tipping.
5. Consider using a physical stop (berm) to prevent reversing into the trench.
Rationale: Trench tipping is a high-risk operation. A trench collapse could engulf
the machine, and any personnel in the trench could be crushed by falling material.
A stop block prevents the truck from reversing over the edge.
Question 6
The operator has been asked to drive the machine onto a transporter/trailer.
a) Who is responsible for the loading operations and
b) state FOUR actions to be considered by the operator before loading
commences?
Correct Answer:
a) The transporter driver is responsible for the loading operation.
b) FOUR actions:
1. Select a level area with sufficient room to manoeuvre.
2. Check for overhead obstructions (wires, bridges).
3. Ensure the machine is clean (to prevent slippage on ramps).
4. Confirm the transporter is suitable and in good condition.
Rationale: The driver of the transporter has legal responsibility for the load and
vehicle combination. The dump truck operator must assist by ensuring their
machine is configured correctly and the loading environment is safe.
