Mobile Crane Operator Flashcards

Under which circumstance is a crack in the windshield of a crane cab okay?

Answer: As long as it causes no visible distortion that would interfere with safe operations

A crack in the windshield of a crane cab is only acceptable if it does not cause any visible distortion that would impede the operator's clear line of sight or interfere with safe operations. Any crack that impairs visibility must be repaired or the windshield replaced immediately to ensure the operator can safely monitor the work area.

Unless the manufacturer states otherwise, what crane capacity chart is appropriate when a crane is set up with 3 of its 4 outriggers extended and the fourth is retracted?

Answer: On-rubber chart

If a crane is set up with fewer than all outriggers fully extended (e.g., three out of four), its stability is compromised compared to a fully outrigged setup. In such situations, the crane's capacity must be downgraded to the 'on-rubber chart' capacity, as this chart reflects a less stable configuration, unless the manufacturer provides specific charts for partial outrigger extension.

When is side loading of crane booms permitted?

Answer: Only with freely suspended loads

Side loading of crane booms is generally prohibited because it introduces bending forces that the boom is not designed to withstand, potentially leading to structural failure. However, it is permissible only with freely suspended loads, as these loads can swing freely and align themselves with the hoist line, thereby minimizing lateral forces on the boom.

What is indicated if an operator makes two audible signals when moving a crane?

Answer: He/she intends to go ahead

In crane operations, two audible signals are a standard communication method used to indicate that the operator intends to move the crane forward or 'go ahead.' This signal alerts personnel in the vicinity of the crane's impending movement, enhancing safety on the job site.

According to ASME, what percentage of the manufacturer's crane rating must not be exceeded if a load test is done on a repaired crane?

Answer: 100%

According to ASME B30.5-2018, Section 5-2.2.2(b)(2), a load test performed on a repaired crane must not exceed 100% of the manufacturer's rated load. This standard ensures that the crane is tested to its full operational capacity without intentionally subjecting it to an overload. Testing at 100% verifies the integrity of the repair and confirms the crane can safely perform its intended functions.

Where is the tipping axis of a crawler crane located?

Answer: It depends if the idler or sprocket are in line or offset from the track rollers

The tipping axis of a crawler crane is not a fixed point; it dynamically shifts based on the crane's configuration and the direction of the load. It is located through the center of the track rollers on the side opposite the load, or through the idler or sprocket if they are aligned with the track rollers. Understanding this variability is crucial for accurately calculating stability and preventing crane overturns.

What should be done with materials placed under overhead energized power lines?

Answer: Not be lifted by crane

OSHA regulations, specifically 1926.1408, strictly prohibit operating cranes where any part of the crane, load, or rigging could come within the minimum approach distance of energized power lines. Placing materials directly under such lines creates an immediate and severe electrocution hazard. Therefore, the safest and mandated practice is to avoid any crane operations in these areas.

Where should the crane's outrigger pads or tracks be placed when working at ground floor level near a cellar wall?

Answer: At least as far back as the depth of the wall below ground

When working near a cellar wall, the ground supporting the crane's outriggers or tracks must be stable enough to bear the significant weight. Placing outriggers too close to the wall can cause the soil beneath the wall's foundation to fail, leading to a collapse. The general safety rule is to position the outriggers at least as far back from the wall as the depth of the wall below ground, ensuring adequate soil support and preventing structural damage.

How should the wheels of a crane be positioned when it is set up for working on outriggers?

Answer: Just high enough off the ground to relieve the tires of crane weight

When a crane is set up for working on outriggers, the outriggers are designed to bear the entire weight of the crane and its load, providing maximum stability. The wheels should be lifted just enough off the ground to relieve the tires of the crane's weight. This prevents the tires from contributing to the support or interfering with the outriggers' stability, ensuring the crane's foundation is solely on the properly deployed outriggers.

What happens to ground bearing pressure if you move a crawler crane from soft ground to harder ground?

Answer: It increases

Ground bearing pressure is the force exerted by the crane's tracks or outriggers over a given area. When a crawler crane moves from soft ground to harder ground, the harder surface may not deform as much, concentrating the load over a smaller effective contact area. This concentration of force over a reduced area results in an increase in ground bearing pressure.