EICA Mobile Crane & Digger Derrick
Questions With Complete Solutions
Course
Eica Crain certification
1. Load Charts
Question:
Explain why it is critical to follow a mobile crane’s load chart.
Answer:
The load chart provides the maximum safe load for each boom length and angle. Ignoring it
can cause overloading, tipping, or structural failure. Always check boom length, radius,
counterweights, and configuration before lifting.
2. Outriggers
Question:
Why must outriggers be fully extended and properly placed on a mobile crane?
Answer:
Outriggers increase stability by widening the base and distributing weight. If partially deployed
or on unstable ground, the crane can tip over under load. Always use pads and level the crane.
3. Boom Angle
Question:
A crane is lifting a 5-ton load at a 20-meter radius. The boom is extended to 25 meters. How
does increasing the boom angle affect the crane’s lifting capacity?
Answer:
Increasing the boom angle reduces the horizontal reach but increases lifting capacity because
the load is closer to the center of rotation. Load charts reflect this: the higher the angle, the
heavier the load the crane can safely lift at that radius.
,4. Ground Conditions
Question:
What ground conditions are considered unsafe for operating a digger derrick?
Answer:
Soft, muddy, or uneven ground
Slopes exceeding manufacturer recommendations
Unstable surfaces like loose gravel or sand without mats
Reason: Instability can cause tipping or boom collapse.
5. Hydraulic Systems
Question:
What is the role of hydraulics in a digger derrick?
Answer:
Hydraulic systems control:
Boom extension/retraction
Winches
Augers for digging holes
Hydraulics allow precise, controlled movement under load, enabling safe lifting and
digging.
6. Load Stability
Question:
A crane operator notices the load swinging during a lift. What should be done?
Answer:
Stop the lift immediately
Lower the load to a safe height
Check rigging, wind, and boom movement
Reposition the crane if necessary
Reason: Swinging can cause crane instability or load drop, endangering personnel and
equipment.
,7. Digger Derrick Safety
Question:
What safety checks are required before using a digger derrick?
Answer:
Inspect hydraulic hoses and connections
Check boom, outriggers, and stabilizers
Test controls and emergency stops
Verify ground conditions and load limits
Purpose: Prevent accidents due to mechanical failure or operator error.
8. Signal Person
Question:
Why is a signal person necessary for crane operations in congested areas?
Answer:
The signal person:
Guides the operator to avoid collisions
Communicates load movement and hazards
Ensures safety when operator visibility is limited
9. Wind Limits
Question:
How does wind affect crane operation?
Answer:
High winds can:
Increase load swing
Reduce crane stability
Exceed manufacturer’s rated wind limits
Solution: Always check load charts for wind limits and suspend lifts above safe wind
speed.
, 10. Digging with Derrick
Question:
While digging with a digger derrick, what is the maximum load on the auger at full extension?
Answer:
Refer to the manufacturer’s load chart.
Maximum rated capacity decreases as boom extends or angle decreases.
Overloading at full extension can tip the truck or damage the boom.
Always operate within specified load ratings and use outriggers for stability.
11. Load Radius Calculation
Question:
A mobile crane has a 10-ton rated load at 6 meters radius. If the load radius increases to 12
meters, what happens to the safe lifting capacity?
Answer:
Lifting capacity decreases as radius increases because leverage on the crane increases. Always
refer to the load chart for exact safe load at the given radius.
12. Boom Extension
Question:
Why is it important to not exceed the boom length specified in the load chart for a given load?
Answer:
Exceeding boom length reduces stability and increases bending stress on the boom, risking
structural failure or tipping.
13. Outrigger Mats
Question:
What is the purpose of using outrigger mats?
Answer:
They distribute load over a larger area, preventing outriggers from sinking into soft ground
and maintaining crane stability.
Questions With Complete Solutions
Course
Eica Crain certification
1. Load Charts
Question:
Explain why it is critical to follow a mobile crane’s load chart.
Answer:
The load chart provides the maximum safe load for each boom length and angle. Ignoring it
can cause overloading, tipping, or structural failure. Always check boom length, radius,
counterweights, and configuration before lifting.
2. Outriggers
Question:
Why must outriggers be fully extended and properly placed on a mobile crane?
Answer:
Outriggers increase stability by widening the base and distributing weight. If partially deployed
or on unstable ground, the crane can tip over under load. Always use pads and level the crane.
3. Boom Angle
Question:
A crane is lifting a 5-ton load at a 20-meter radius. The boom is extended to 25 meters. How
does increasing the boom angle affect the crane’s lifting capacity?
Answer:
Increasing the boom angle reduces the horizontal reach but increases lifting capacity because
the load is closer to the center of rotation. Load charts reflect this: the higher the angle, the
heavier the load the crane can safely lift at that radius.
,4. Ground Conditions
Question:
What ground conditions are considered unsafe for operating a digger derrick?
Answer:
Soft, muddy, or uneven ground
Slopes exceeding manufacturer recommendations
Unstable surfaces like loose gravel or sand without mats
Reason: Instability can cause tipping or boom collapse.
5. Hydraulic Systems
Question:
What is the role of hydraulics in a digger derrick?
Answer:
Hydraulic systems control:
Boom extension/retraction
Winches
Augers for digging holes
Hydraulics allow precise, controlled movement under load, enabling safe lifting and
digging.
6. Load Stability
Question:
A crane operator notices the load swinging during a lift. What should be done?
Answer:
Stop the lift immediately
Lower the load to a safe height
Check rigging, wind, and boom movement
Reposition the crane if necessary
Reason: Swinging can cause crane instability or load drop, endangering personnel and
equipment.
,7. Digger Derrick Safety
Question:
What safety checks are required before using a digger derrick?
Answer:
Inspect hydraulic hoses and connections
Check boom, outriggers, and stabilizers
Test controls and emergency stops
Verify ground conditions and load limits
Purpose: Prevent accidents due to mechanical failure or operator error.
8. Signal Person
Question:
Why is a signal person necessary for crane operations in congested areas?
Answer:
The signal person:
Guides the operator to avoid collisions
Communicates load movement and hazards
Ensures safety when operator visibility is limited
9. Wind Limits
Question:
How does wind affect crane operation?
Answer:
High winds can:
Increase load swing
Reduce crane stability
Exceed manufacturer’s rated wind limits
Solution: Always check load charts for wind limits and suspend lifts above safe wind
speed.
, 10. Digging with Derrick
Question:
While digging with a digger derrick, what is the maximum load on the auger at full extension?
Answer:
Refer to the manufacturer’s load chart.
Maximum rated capacity decreases as boom extends or angle decreases.
Overloading at full extension can tip the truck or damage the boom.
Always operate within specified load ratings and use outriggers for stability.
11. Load Radius Calculation
Question:
A mobile crane has a 10-ton rated load at 6 meters radius. If the load radius increases to 12
meters, what happens to the safe lifting capacity?
Answer:
Lifting capacity decreases as radius increases because leverage on the crane increases. Always
refer to the load chart for exact safe load at the given radius.
12. Boom Extension
Question:
Why is it important to not exceed the boom length specified in the load chart for a given load?
Answer:
Exceeding boom length reduces stability and increases bending stress on the boom, risking
structural failure or tipping.
13. Outrigger Mats
Question:
What is the purpose of using outrigger mats?
Answer:
They distribute load over a larger area, preventing outriggers from sinking into soft ground
and maintaining crane stability.
