NCCCO Service Truck Crane Operator 4 — Questions and Answers
Question 1: What is the maximum rated capacity for most service truck cranes (knuckle boom or telescopic)?
- 100 tons
- Typically 3-14 tons depending on configuration, much less than mobile cranes (Correct answer)
- 50 tons minimum
- Same as full-size mobile cranes
Correct answer: Typically 3-14 tons depending on configuration, much less than mobile cranes
Service truck cranes (also called boom trucks or knuckle booms) typically have capacities between 3-14 tons, making them suitable for lighter lifts like HVAC units, construction materials, and utility work.
Question 2: What is unique about the outrigger requirements for service truck cranes?
- They don't need outriggers
- Outriggers must be fully extended AND the truck must be on firm, level ground — partial extension drastically reduces capacity (Correct answer)
- Outriggers are optional for loads under 2 tons
- Only rear outriggers are needed
Correct answer: Outriggers must be fully extended AND the truck must be on firm, level ground — partial extension drastically reduces capacity
Service truck crane load charts often show dramatically different capacities for full vs. partial outrigger extension. Operating with partially extended outriggers without the correct chart can lead to tip-over.
Question 3: When operating a service truck crane near the rear of the truck, what special consideration applies?
- Rear operations are always the most stable
- Capacity over the rear may be different from over the side due to the truck's stability geometry (Correct answer)
- Only lift over the rear when parked uphill
- Never operate over the rear of the truck
Correct answer: Capacity over the rear may be different from over the side due to the truck's stability geometry
Service truck cranes have different stability characteristics in different quadrants. Operating over the rear, side, and front each have different rated capacities based on the truck's outrigger configuration and center of gravity.
Question 4: What CDL requirement may apply to service truck crane operators?
- No CDL ever required
- Depending on truck GVWR, a CDL may be required to drive the truck on public roads (Correct answer)
- CDL is only for operators over 21
- CDL replaces crane certification
Correct answer: Depending on truck GVWR, a CDL may be required to drive the truck on public roads
Service trucks exceeding 26,000 lbs GVWR require a CDL to operate on public roads. This is separate from the crane operator certification — both may be needed.
Question 5: What is the most common cause of service truck crane accidents?
- Engine failure
- Overloading beyond rated capacity, often due to using incorrect load chart or not accounting for outrigger configuration (Correct answer)
- Tire blowouts
- Electrical problems
Correct answer: Overloading beyond rated capacity, often due to using incorrect load chart or not accounting for outrigger configuration
The most common cause is exceeding capacity, frequently because operators use the wrong section of the load chart (wrong outrigger configuration) or don't account for rigging weight and dynamic loads.
Question 6: A service truck crane is being used to set a rooftop HVAC unit. What is the primary concern?
- Noise from the unit
- The load radius increases as the unit is lifted higher and moved over the building edge, potentially exceeding capacity (Correct answer)
- The HVAC unit might be damaged
- Weather conditions for HVAC installation
Correct answer: The load radius increases as the unit is lifted higher and moved over the building edge, potentially exceeding capacity
As the load goes up and out (over the building edge), the operating radius increases significantly. The crane may be within capacity at ground level but exceed capacity at the placement radius and height.
NCCCO Service Truck Crane Operator 4
What is the maximum rated capacity for most service truck cranes (knuckle boom or telescopic)?