Chapter 10: Commercial/ Heavy Vehicle Stabilization Operations Flashcards Preview

Principles of Vehicle Extrication > Chapter 10: Commercial/ Heavy Vehicle Stabilization Operations > Flashcards

Flashcards in Chapter 10: Commercial/ Heavy Vehicle Stabilization Operations Deck (31)
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Many commercial vehicles equip each axle with ____; rescuers can use these locations for stabilization. In addition, some commercial vehicles have specially designed ____ that can also be used as contact points for cribbing or jacks.

* a piece of tubing welded on the axle near each wheel
* jack plates and engine supports


Jacks should be equipped with ____ that allow rescuers to operate them from the outside perimeter of the vehicle.



Rescuers must ____ they need to stabilize before beginning stabilization operations.

* calculate the load


How can rescuers estimate the weight of the commercial/ heavy vehicles involved in the extrication?.

* 20,000 pounds for each drive axle
* Thin or slim profile tires on a steering axle = 10,000 pounds
* balloon wide profile tires on a steering axle = 25,000 pounds


The majority of trucks involved in collisions will be found ____



What makes a trucks center of gravity significantly higher than that of other vehicles?

The distance between the road surface and the bottom of the chassis is significantly greater.


On cab over units, rescuers should secure the cab with ____ to prevent it from tilting forward unexpectedly during extrication operations.

* rope, webbing, or chains


On truck cabs mounted on air suspension systems rescuers should ____ as part of stabilization.

marry the cab to the chassis to minimize movement from the air suspension system


To marry the cab to the frame on a truck with an air suspension system rescuers should ____

* fill the voids on the cab with cribbing and secure the cab to the frame with a tensioning device.


To stabilize a trailer attached to the truck requiring extrication operations, rescuers should ____

* chock the wheels of the trailer, confirm the kingpin is locked, and lower the landing gear.



Attaching pin on a semitrailer that connects with pivots within the lower coupler of a truck tractor or converter dolly while coupling the two units together.


In tractor trailer accidents rescuers should consider ____ as an added means of vehicle stabilization.

applying the air brake system


A major portion of applying the air brake system as an added means of stabilization in a tractor trailer incident is ____. Rescuers can ____ to disconnect the air system.

* disconnecting the air system from the tractor trailer.
* disconnect the glad hand connection


After the air system has been disengaged during a tractor trailer incident, the trailer brakes will ____

lock with the spring brake mechanism when the pressure falls below 20 - 40 psi.


Rescuers should only disconnect glad hands after ____

completing initial stabilization


To disconnect glad hand connections rescuers should ____

turn the connection approximately 90 degrees and pull the connections apart.


A medium or heavy truck on its side can sometimes ____ to stabilize than other smaller vehicles because ____.

* be easier
* the weight and shape of these trucks often make them relatively stable when they come to rest.


To stabilize a side-resting truck, rescuers should ____. Rescuers may need to ____ because of the roundness of the cab's roof edge.

* install cribbing or other supports at the cab's door posts.
* invert step chocks before sliding them under the vehicle


When deciding how to stabilize a truck that rests in an unusual position, rescue personnel should ____

consider the vehicles center of gravity, mass, cargo, as well as the capabilities of their equipment.


If a vehicle is wedged under another vehicle or object, rescuers should ____

attempt to limit if not eliminate the vehicles reaction when they remove the overlying object.


If a truck stops on a steep slope or hangs over the edge of a bridge or cliff, rescuers can ____

use cribbing and/or rigging to offset the forces of gravity and secure the vehicle in place.


Bombproof Anchor Point

(1) Slang reference to an anchor that is absolutely immovable, such as a huge boulder, a large tree, or a fire engine.
(2) Any anchor point capable of withstanding forces in excess of those that might be generated by the rescue operation or even catastrophic failure (and resultant shock load) of a raising or lowering system.


When chocking wheels of a bus, rescuers should use ____

wheel chocks and not pieces of cribbing.


Rescuers should only consider an anchor point bomb proof if ____

the weight of any object attached to that anchor absolutely will not move the anchor point.


Unless rescuers are positive that a bus has a mechanical suspension system, they should ____

treat the bus as if it has an air suspension system.


Because most transit and commercial buses do not have a rigid frame, they have specially designed ____ for use as contact points for cribbing or jacks.

jack plates


On transit buses jack plates are located ____

slightly behind each axle, near each wheel.


On commercial buses jack plate are located ____

under the body between the two rear axles and in back of the front axle.


Rescuers should support ____ jack plates on a bus to completely stabilize the vehicle.

all four


If hydraulic jacks are used to lift a bus, jacks of at least ____ capacity should be used.

8 ton