Four Defects, One Bus, and a Dispatcher in a Hurry
It is 5:40 a.m. in February. You are assigned a 47-passenger transit bus for a 6:15 a.m. commuter run that includes a long, steep downgrade. During the walk-around you find four problems: the left rear turn-signal lamp does not flash; with the engine at fast idle, the air-pressure gauge climbs from 60 to 85 psi in about 90 seconds; the fire extinguisher gauge needle rests in the red recharge zone; and the rear emergency door's audible warning does not sound when you open the door from inside. The dispatcher says the bus is needed because the replacement is 40 minutes away, and tells you to 'write it up later.' The temperature is 18°F, and passengers are already waiting in the terminal. You have the keys, the pre-trip form, and a two-way radio.
1. Which of the four findings make the bus out of service, and why? Address each finding separately.
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All four findings are out-of-service until corrected.
- Left rear turn signal: Required lighting must work. A dead turn signal means you cannot legally or safely signal a lane change, and other drivers may not see your intention. Out of service.
- Air build-up: A typical dual air system should build from 85 to 100 psi within about 45 seconds at fast idle, and the low-pressure warning should operate below 60 psi. Climbing from 60 to 85 psi in 90 seconds is far too slow. The bus may not maintain adequate pressure for a steep downgrade, so it is out of service until the compressor, governor, or leak is diagnosed.
- Fire extinguisher: A gauge in the red means the extinguisher is not charged. A charged extinguisher is required emergency equipment; replace it or install a spare before boarding.
- Rear emergency door warning: The audible warning is part of the exit safety system. Without it, you cannot confirm the exit is secure, and a passenger could open it unknowingly. Out of service until repaired.
Do not treat any of these as a 'write it up later' item.
2. What sequence of actions do you take before any passenger boards, and what do you say to the dispatcher?
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- Keep the terminal doors closed and passengers off the bus. Place the bus in out-of-service status.
- Secure it: parking brake set, transmission in neutral, engine off or as required, keys controlled.
- Complete the pre-trip form: record each defect, time, odometer, plate or VIN, and take photos.
- Radio dispatch with the facts: 'Bus 47 is out of service: inoperative left rear turn signal, slow air build-up from 60 to 85 psi in 90 seconds, extinguisher in the red, and no rear emergency-door warning. I need a replacement.'
- If dispatch says to write it up later, refuse: 'I cannot operate a bus with these safety defects. Please send a supervisor or another coach.'
- Ask for a replacement or authorize delay/cancellation. Tell waiting passengers there is a delay; do not board them.
A dispatcher cannot override the driver's responsibility to refuse an unsafe vehicle. Document the instruction and your refusal.
3. After the replacement arrives, what defect-reporting and post-trip steps apply to the original bus?
Read the worked answer
- Keep the original bus red-tagged or out of service until a qualified mechanic repairs it.
- The pre-trip defect report must go to maintenance. In a CMV operation, the driver vehicle inspection report and the mechanic's repair certification are part of the record.
- List each defect separately, not as 'misc. defects': turn signal, air build-up, extinguisher, and emergency-door warning. Include date, time, mileage, and your name.
- Do not accept the bus back into service unless the repairs are complete and you re-check the items: signal flashes, air builds to governor cut-out, extinguisher is charged, and the exit warning sounds.
- If the bus is repaired and returned, a new pre-trip inspection is required before passengers board.
- Document the delay or refusal in an operations or incident report per company policy, and keep a copy.