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You fan the service brake down during a static check and the low-air warning does not come on until well below 60 psi. Why is that a defect?
- A.A lower warning point gives the brakes more power
- B.The warning should only sound with the engine off
- C.The warning is optional equipment on air brake trucks
- D.The warning must activate before pressure falls below 60 psi so the driver gets advance notice of air loss
Correct answer
D. The warning must activate before pressure falls below 60 psi so the driver gets advance notice of air loss
Why
The light and buzzer are the driver's first alert that air is being lost faster than it is replaced. A device that waits until pressure is far below 60 psi steals the reaction time the warning exists to provide.
Manual topic: Air Brakes - Low Air Warning · From the General Knowledge practice bank (GK-124).