Question 19 AEL01 - Assistant Engineer - Limited

The Correct Answer is D **Explanation for Option D (Correct Answer):** Before opening any hydraulic system for servicing or repair, the primary safety concern is the potential release of stored energy, which, in this context, is high-pressure hydraulic fluid. Hydraulic systems, especially those used for starting large diesel engines, operate at extremely high pressures (often thousands of psi). If a component, hose, or connection is opened while under pressure, the sudden release of fluid can cause catastrophic injury, including injection injuries, severe bruising, or whipping hose injuries. Therefore, it is a mandatory safety protocol to **bleed off all hydraulic pressure from the system** (depressurize the accumulator and lines) to ensure the system is at zero gauge pressure before beginning work. **Explanation of Incorrect Options:** * **A) Place all control levers in the "HOLD" position:** Placing levers in a specific position might lock out some movement, but it does not remove the stored high pressure within the accumulator or hydraulic lines, which is the major hazard when opening the system. * **B) Ensure that the hydraulic fluid reservoir is full:** The fluid level in the reservoir is an operational check, not a safety prerequisite for maintenance. Whether the reservoir is full or low has no bearing on the dangerous high pressure stored in the active system components. * **C) Block all hydraulic hoses using high-pressure covers:** High-pressure covers are typically used to protect connectors during storage or cleaning, or sometimes as localized protection during specific repairs. They are not a standard procedure for depressurizing the entire system before opening it for general service or repair. The essential step is removing the pressure, not simply covering the hoses.