CPCS A04 Crane/Lifting Operations — Tower Crane (NOCN/CPCS, UK)

What is the principal operational difference between a trolley (saddle) jib tower crane and a luffing jib tower crane?

• AA trolley jib stays horizontal while a trolley moves the hook; a luffing jib raises and l…
• BA trolley jib can rotate 360 degrees, whereas a luffing jib is fixed in slew direction.
• CA luffing jib has no hoist rope and uses hydraulic cylinders directly to lift loads.
• DA trolley jib can only be mounted on traveling bases, while a luffing jib must be static.

Why are luffing jib tower cranes predominantly selected for congested urban construction sites?

• AThey can operate at high jib angles to clear adjacent oversailing restrictions and tall n…
• BThey require zero counter-ballast weight at the rear of the slewing upper structure.
• CThey are immune to high wind speeds and never require weather-vanning.
• DThey can lift double their maximum rated capacity compared to trolley jib cranes.

What is the primary function of central ballast ballast blocks on a bottom-slewing self-erecting tower crane?

• ATo stabilize the non-slewing lower chassis against overturning moments during operation a…
• BTo provide emergency braking force for the slewing mechanism.
• CTo act as a anchor weight for the hoist rope dead-end reeving.
• DTo adjust the working height of the telescopic mast during operation.

Under UK HSE guidance and BS 7121-5, what device must continuously measure and display wind speed to the tower crane operator?

• AAn anemometer fitted at the highest point of the crane (usually tower top or jib tip).
• BA barometric pressure sensor installed inside the operator cab.
• CA strain gauge mounted on the main hoist wire rope.
• DA tachometer attached to the slewing ring pinion.

What does the term 'weather-vanning' mean when leaving a top-slewing tower crane out of service?

• AReleasing the slew brake so the jib free-slews and points downwind like a wind vane to mi…
• BLocking the slew brake tightly in the direction of the building under construction.
• CLowering the hook block onto the ground and tying the jib to scaffolding with steel wire…
• DEnclosing the operator cab in protective waterproof canvassing.

What primary safety device prevents a tower crane from lifting a load that exceeds the maximum rated load moment?

• ARated Capacity Limiter (RCL) / Load Moment Limiter.
• BSlew limit switch.
• CTrolley buffer stop.
• DTelescoping lock pin.

During a 'blind lift' where the crane operator cannot see the load or landing area, how must instructions be communicated?

• AVia a dedicated two-way radio channel or relay Slinger/Signaller using standardized BS 71…
• BBy the operator leaning out of the cab window to visually locate the load.
• CUsing mobile phone text messages between the site manager and operator.
• DBy sounding the crane air horn once for up and twice for down.

What must the tower crane operator check regarding the hook block during daily pre-operational inspections?

• ASafety latch condition, swivel rotation, sheaves, frame integrity, and hook opening/wear.
• BThat the hook is painted yellow only.
• CThat the hook weight matches the total ballast of the crane base.
• DThat the hook block is greased every 30 minutes.

What is the purpose of a hoist upper limit switch on a tower crane?

• ATo cut off hoisting motion before the hook block collides with the trolley or jib structu…
• BTo stop the trolley from traveling outward past the jib tip.
• CTo automatically disengage the main power generator.
• DTo prevent the operator from slewing left.

Before erecting or telescoping a tower crane, what weather factor must be checked against the erection manual?

• AMaximum allowable wind speed for erection/climbing operations.
• BRelative humidity.
• CAmbient air pressure in millibars.
• DCloud cover percentage.

What action should the operator take if the anemometer alarm sounds while lifting a load near the in-service wind limit?

• ASafely land the current load, cease further lifting operations, and prepare the crane for…
• BIncrease hoist speed to finish the lift before wind increases.
• CSlew the crane rapidly in full circles to stabilize the jib.
• DIgnore the alarm until site management telephones the cab.

What parameter is calculated by multiplying the suspended load mass by the operating radius from the center of slewing?

• ALoad moment (tonne-metres or kNm).
• BGross torque of the hoist motor.
• CWind friction coefficient.
• DBase concrete cure rate.

Where must the trolley be parked on a horizontal saddle-jib crane when preparing for out-of-service weather-vanning?

• AAt the specific parking radius designated by the crane manufacturer (usually near the jib…
• BAt the extreme tip of the jib.
• CIn the exact middle of the jib span.
• DDirectly above the cab door.

Why must counter-ballast weights be accurately weighed and verified prior to installation on the counter-jib?

• AIncorrect ballast mass alters structural balance, leading to backward overturning when un…
• BTo calculate fuel consumption rates of the generator.
• CTo ensure the crane cab heating system functions correctly.
• DTo determine the maximum speed of the trolley.

In UK radio signalling protocols, what must the Slinger/Signaller state at the beginning of every radio transmission to the crane operator?

• AThe specific crane identification call sign and clear directional instruction.
• BThe current time and weather forecast.
• CThe site manager's full name and phone number.
• DThe weight of the crane base anchor.

What is the primary danger of operating a tower crane in conditions where wind gusts exceed manufacturer limits?

• ADynamic structural overloading, loss of load control, side-loading on jib, and potential…
• BExcessive fuel usage in the electrical generator.
• CRapid wearing of cab windshield wiper blades.
• DOverheating of the operator seat cushion.

What pre-climb structural check must be performed on the mast sections and climbing frame before telescoping a tower crane?

• AInspect mast bolts/pins, guide shoes, hydraulic climbing ram, lock pawls, and ladder/plat…
• BCheck that all cab windows are opened halfway.
• CEnsure the hook block is painted red.
• DDrain all hydraulic oil from the climbing power pack.

If main electrical power fails while a load is suspended, how should the operator lower the load safely?

• AUtilize the manual emergency hoist brake release procedure in accordance with manufacture…
• BJump out of the cab onto the building roof immediately.
• CDisengage the slewing gear and allow the load to drop freely.
• DWait for wind to blow the load down to the ground.

What is an expendable base anchor angle (cast-in anchor) used for in tower crane installation?

• ATo anchor the bottom mast section directly into a reinforced concrete foundation block.
• BTo secure temporary handrails around the site perimeter.
• CTo support the weight of the mobile erection crane outriggers.
• DTo connect the radio antenna to the mast top.

What indicator inside the cab alerts the operator when the crane approaches 90% to 100% of its rated capacity?

• AVisual warning light (amber/red) and audible warning buzzer from the RCI/RCL system.
• BA flashing green light indicating safe unlimited capacity.
• CAn automatic cab door lock engagement.
• DA change in engine exhaust smoke color.

What is the standard hand signal under BS 7121 for 'Emergency Stop' during crane operations?

• ARapidly waving both arms horizontally back and forth.
• BPointing one finger upward and making small circles.
• CHolding both hands together in front of the chest.
• DTapping the top of the safety helmet repeatedly.

What does a trolley inner/outer limit switch prevent on a saddle jib tower crane?

• APrevents the trolley from running off the end of the jib tracks or crashing into the towe…
• BPrevents the hoist drum from spinning backwards during free fall.
• CPrevents the cab heater from drawing too much current.
• DPrevents the crane from slewing beyond 180 degrees.

Why must the hook block be raised close to the jib structure before leaving the crane in out-of-service weather-vanning mode?

• ATo prevent loose hook blocks or slings from catching on surrounding structures, trees, or…
• BTo compress the trolley wire rope springs.
• CTo keep the hook warm during cold weather.
• DTo allow site workers to park vehicles directly under the mast base.

Under LOLER 1998, what is the statutory period for Thorough Examination of a tower crane installation on a construction site?

• AAt least every 14 months (or 6 months if lifting persons), or in accordance with an exami…
• BEvery 5 years.
• CEvery 10 years.
• DOnly when a component visually fails.

What is the recommended operator response if radio contact is lost mid-lift during a blind lifting operation?

• AStop all crane movements immediately and wait until clear communication is restored.
• BContinue moving the load in the last instructed direction for 30 seconds.
• CDrop the load rapidly to the ground.
• DSlew the crane blindly towards the center of the site.

What visual check must be performed on the main wire ropes during daily checks?

• ACheck for broken wires, kinking, bird-caging, flattening, corrosion, correct drum spoolin…
• BCheck that the rope matches the paint color of the mast.
• CMeasure the length of the rope with a wooden folding rule while under full load.
• DVerify that the rope is tied in a knot at the hook block.

What type of jib tower crane alters radius by raising and lowering the jib angle using a luffing winch or hydraulic ram?

• ALuffing jib tower crane.
• BSaddle jib tower crane.
• CArticulated overhead gantry crane.
• DFixed-boom Derrick crane.

Why must ground bearing pressure calculations be prepared by a qualified structural engineer prior to tower crane installation?

• ATo ensure the soil or supporting structure can safely withstand maximum combined foundati…
• BTo obtain permission from the local water authority.
• CTo calculate the total cost of diesel fuel required.
• DTo decide the colour scheme of the tower mast.

What is the function of anti-collision systems on multi-tower crane construction sites?

• ATo automatically warn operators and slow/stop crane movements before jibs, ropes, or load…
• BTo prevent mobile phones from ringing inside the operator cab.
• CTo lock the main hoist drum when the wind exceeds 10 mph.
• DTo automatically steer delivery trucks on site.

What document must the operator complete and sign before starting work at the beginning of each shift?

• ADaily pre-operational check sheet / operator logbook.
• BTax return declaration form.
• CBuilding construction completion certificate.
• DDelivery note for concrete ballast.

On a luffing jib tower crane, what additional hazard is created when the jib is raised to its maximum steep angle in windy conditions?

• AHigh wind gusts from behind can blow the jib backward over the top of the crane tower if…
• BThe hoist rope will automatically unspool from the drum.
• CThe operator cab will rotate upside down.
• DThe central ballast blocks will slide off the chassis.

How does increasing the number of falls of hoist rope reeving (e.g. from 2-fall to 4-fall) affect crane lifting capacity and speed?

• ADoubles maximum lifting capacity while halving maximum line hoisting speed.
• BHalves maximum lifting capacity while doubling line hoisting speed.
• CIncreases both lifting capacity and hoisting speed by four times.
• DHas no effect on capacity or speed; it only alters rope wear.

What structural component connects a free-standing tower crane mast to an adjacent building frame when height exceeds free-standing limits?

• AIn-service mast ties / collar ties.
• BExpander springs.
• CTrolley ballast cables.
• DGuy wires anchored to timber fences.

What key calculation must be checked when placing a mobile crane on site to assemble a tower crane foundation and mast sections?

• AOutrigger mat surface area and soil bearing pressure under maximum rigging loads.
• BThe wind resistance of the mobile crane driver's seat.
• CThe paint color match between mobile crane and tower crane.
• DThe distance to the nearest fuel filling station.

Why are dual-anemometer or calibrated digital wind telemetry systems required on high-rise tower crane installations?

• AWind speed increases significantly with height above ground due to boundary layer wind sh…
• BTo provide backup power to the operator cab air conditioner.
• CBecause one anemometer is dedicated solely to measuring rainfall.
• DTo measure the rotational speed of the hoist motor.

If a top-slewing tower crane's slew brake remains accidentally locked during a severe storm, what structural damage can occur?

• ASide wind pressure creates massive bending and twisting moments on the jib and mast, pote…
• BThe hoist wire rope will melt due to friction.
• CThe operator seat hydraulic adjustment will fail.
• DThe ground anchor bolts will increase in length.

What is the function of a 'trolley derailment catcher' (trolley drop stop) on a tower crane saddle jib?

• ATo prevent the trolley from falling off the jib chord if a trolley wheel axle fractures.
• BTo stop the hook block from rotating when lifting concrete buckets.
• CTo automatically apply the main hoist brake during power outages.
• DTo guide the operator ladder inside the mast tower.

Under BS 7121-5, what action must be taken if radio interference causes erratic speech or signal dropout during a crane operation?

• AImmediately halt crane movement, switch to a clear dedicated radio frequency, and re-test…
• BIncrease hoisting speed to complete the lift quickly.
• CShout instructions out of the building windows.
• DIgnore the interference as long as visual cues are partially visible.

What is the role of a 'top-climbing cage' (telescoping cage) during tower crane height extension?

• AIt surrounds the upper mast and uses hydraulic rams to lift the slewing unit and jib, cre…
• BIt carries site personnel up and down the outside of the mast during normal working hours.
• CIt stores spare counter-weight concrete blocks.
• DIt acts as a temporary shelter for site management.

What check must be performed on hydraulic luffing cylinders on a hydraulic-luffing tower crane during daily inspections?

• AInspect cylinder rods for scoring, check seal leaks, hose condition, holding valve integr…
• BDrain hydraulic fluid into a bucket to check color.
• CDisconnect hydraulic lines to test pressure manually.
• DPaint the cylinder chrome rod with protective enamel.

What structural condition occurs if a tower crane is subjected to 'out-of-verticality' (plumbness error) exceeding manufacturer tolerances during mast assembly?

• AAdditional eccentric bending moments are induced in mast sections, severely reducing rate…
• BThe slewing motor will run at double speed.
• CThe anemometer will give falsely low wind readings.
• DThe hoist wire rope will automatically shorten.

What is the purpose of a 'slack rope limit switch' fitted to a tower crane hoist drum or trolley winch?

• ATo stop winch drum rotation if wire rope loses tension, preventing wire rope crossover, b…
• BTo increase hoisting speed when carrying light loads.
• CTo signal the site office when the hook reaches ground level.
• DTo measure the weight of concrete skips.

On a rail-mounted tower crane, what device clamps the crane base frame to the steel rails when out of service or during high wind?

• ARail clamps / storm anchors.
• BTrolley buffers.
• CSlew ring pins.
• DHydraulic outrigger jacks.

Under what circumstance must a tower crane's anemometer be recalibrated or recertified?

• AAt statutory inspection intervals, after physical damage/lightning strikes, or whenever r…
• BEvery time the operator changes shifts.
• COnly when the crane is dismantled at the end of a project.
• DNever; anemometers are permanently calibrated at the factory.

Why must the operator ensure that no lifting slings or tackle are left hanging from the hook block when leaving the crane in weather-vanning mode?

• AHanging slings can catch on nearby structures during 360-degree free-slewing, causing str…
• BSlings will absorb rain and become too heavy for the hook.
• CSlings will attract lightning strikes to the hook block.
• DSite thieves may climb the hoist rope to steal the slings.

What specific hazard occurs if a tower crane operator slews rapidly and then abruptly stops the slewing motion with a suspended load?

• AThe load will swing violently outward (side-sway), introducing high torsional stress on t…
• BThe main hoist rope will instantly un-reeve from the sheaves.
• CThe counter-weights will detach from the counter-jib.
• DThe anemometer will stop spinning.

What is the function of a 'trolley wire rope re-tightening (tensioning) mechanism' on a saddle jib crane?

• ATo maintain correct tension in forward and reverse trolley drive ropes, preventing rope s…
• BTo adjust the operator seat angle.
• CTo increase the lifting capacity of the main hook.
• DTo automatically lock the slew ring during climbing.