Controls & Indicators - Hydraulics - Airframes & Aircraft Systems #12

Summary

This lesson delves into hydraulic system controls and indicators, contrasting older aircraft's mechanical systems with modern aircraft's electronic displays. It covers reservoir fluid level checks, temperature monitoring, shutoff valves, and backup pumps. Modern systems use electronic screens to display reservoir levels, pump statuses, and system pressures, with automated warnings for failures. The video provides a comprehensive overview of hydraulic system components and their operation in both generations of aircraft.

Takeaways

• 🔧 Older aircraft hydraulic systems have a physical control and indicating panel, while newer aircraft display this information on electronic screens.
• ✈️ Aircraft with multiple hydraulic systems require sophisticated control and indicating systems for effective operation.
• 💡 Reservoirs in older systems may have a clear window or a float type contents unit to monitor fluid levels, with a low quantity light indicating when levels are low.
• 🌡️ Fluid temperature is monitored to prevent overheating, with a high-temperature light illuminating if temperatures exceed safe levels.
• 🔥 A firewall shutoff valve is used to cut off fluid flow at the pump inlet in case of an engine fire, with a flow bar indicating when the valve is open.
• 🔄 Pump shutoff switches control solenoid-operated depressurizing valves, which block delivery to the system but allow pump cooling and lubrication.
• 🔌 Backup pumps in systems B and C are driven by air turbine motors and are controlled by switches on the hydraulic panel.
• 🔧 Engine-driven pump case drain return fluid temperature is monitored to check pump condition, with warning lights for excessive temperatures.
• 🔄 Power transfer units use hydraulic motors to drive pumps in other systems, controlled by switches on the hydraulic panel.
• ⚙️ The ram air turbine is deployed to power the primary flight controls and wheel brakes, with system accumulators having pressure gauges for monitoring.
• 📊 Modern aircraft display hydraulic system information on electronic screens, with graphical displays for reservoir quantities and pump statuses, and automatic warnings for failures.

Q & A

What are the primary functions of the hydraulic system in aircraft?

The hydraulic system in aircraft is used for controlling various components such as the primary flight controls and wheel brakes, and it also provides power assistance for movements.

How many hydraulic systems does an older large airliner typically have?

An older large airliner typically has four separate hydraulic systems labeled A, B, C, and D.

What is the purpose of a clear window in the hydraulic reservoir?

A clear window in the hydraulic reservoir allows for visual inspection of fluid levels during servicing.

What does the reservoir low quantity light indicate?

The reservoir low quantity light illuminates when the fluid level falls below a predetermined level, indicating that the fluid quantity is low.

What is the function of the firewall shutoff valve in the hydraulic system?

The firewall shutoff valve is used to shut off fluid at the pump inlet. Pulling the engine fire switch will close this valve.

How do backup pumps in the B and C systems of an aircraft operate?

Backup pumps in the B and C systems are air turbine motor driven and are controlled by switches on the hydraulic control panel.

What is the purpose of the ram air turbine in the hydraulic system?

The ram air turbine is deployed to power hydraulic system P, which is used purely for the primary flight controls and wheel brakes.

How are system pressures monitored in aircraft with electrically operated pressure gauges?

System pressures are monitored using electrically operated pressure gauges on the hydraulics panel, and a pressure relay is often fitted to protect the system from leaks.

What does the electronic screen display in modern aircraft regarding the hydraulic system?

In modern aircraft, the electronic screen displays the hydraulic system configuration, reservoir quantities, pump status, system pressure, and configurations of turbine and power transfer units.

How are the statuses of the hydraulic pumps indicated on the electronic screen of an Airbus aircraft?

Pump statuses are indicated by boxes showing a solid line for an operating pump and a cross-line for a pump that is not operating.

What is the function of the push buttons on the hydraulic control panel of a modern aircraft?

The push buttons on the hydraulic control panel control the engine-driven pump depressurizing valves and have integrated pump low-pressure lights.

What is the purpose of the 'orgs' position on the number four system switch?

The 'orgs' position on the number four system switch is used to operate a low volume electrically powered pump to pressurize the brakes prior to engine start or when the aircraft is being towed.