Chapter 7, Stabilizing The Apparatus

Question 1

What is the most critical aspect of preparing an aerial apparatus for use?

Answer 1

The apparatus stabilization process.

Question 2

When parked, with the aerial device stowed, where is the apparatus center of gravity?

Answer 2

Along the longitudinal midline, between the front and rear axles.

Question 3

What is the gravity circle of an aerial apparatus?

Answer 3

The “safety zone” that surrounds the center of gravity on an aerial apparatus.

Question 4

How can the aerial apparatus tip over, with the aerial device deployed?

Answer 4

If the gravity circle extends beyond the base of stability, the apparatus can tip over.

Question 5

Where will the center of gravity move, if the aerial apparatus is parked on a lateral grade (slope)?

Answer 5

The center of gravity (and the gravity circle) will be shifted to the lower side.

Question 6

What will overloading an aerial apparatus do to the gravity circle?

Answer 6

It will cause the gravity circle to expand, possibly beyond the base of stability.

Question 7

What are the most common stabilizer devices on an aerial apparatus?

Answer 7

• straight jack (extend down from corners of chassis)
• A frame/X (extend down and away from chassis)
• Box (extend straight away from truck, then straight down; most common in newer aerials)

Question 8

To deploy stabilizers/aerial device, the hydraulic system must be engaged. How is this done?

Answer 8

By activating the power take-off switch (PTO).

Question 9

What are the 4 types of PTO activation switches?

Answer 9

• pneumatic (needs 50 to 140 psi)
• electric
• hydraulic
• combination of these three

Question 10

What is the PTO system?

Answer 10

A rotating shaft that transfers the power from the engine to the auxiliary equipment.

Question 11

What is a Jake Brake?

Answer 11

It alters a diesel engines compression in order to slow the vehicle.

Question 12

What switch is used to provide hydraulic power to the stabilizing system?

Answer 12

The selector valve.

Question 13

What are the 2 ways that a raised aerial apparatus can be uneven?

Answer 13

• laterally (side to side, easiest to correct)

- longitudinally (end to end)

Question 14

Correction of lateral unevenness can be achieved on what grades?

Answer 14

Up to 5 or 6 percent.

Question 15

If an aerial apparatus is stabilized on a hill, on what side should the aerial device be raised?

Answer 15

Over the uphill side of the apparatus.

Question 16

When the aerial apparatus is setting up on a longitudinal grade, how should the aerial device be operated?

Answer 16

Directly over the front or the rear of the vehicle.

Question 17

After stabilizers have been fully deployed, the driver must ensure that stabilizers are locked. How is this done?

Answer 17

Activate the interlock feature (it prevents the flow of hydraulic fluid into or out of the stabilization system).