At low engine speed, 4th-stage bleed air is insufficient to satisfy pneumatic demand. How does the system supplement the bleed-air supply?, The Pressure Regulating Shutoff Valve closes the 4th-stage path and routes all pneumatic demand directly to the 10th-stage manifold., The High Pressure Shutoff Valve opens and meters 10th-stage bleed air using Intermediate Manifold Pressure sensor feedback., The Intermediate Pressure Check Valve is electrically driven open to connect the 10th-stage and 4th-stage manifolds., The High Pressure Shutoff Valve loses electronic control from the Integrated Air Systems Controller but still has pneumatic supply. What pressure-control behaviour is expected?, The valve reverts to pneumatic backup regulation at approximately 65 pounds per square inch gauge., The valve immediately spring-closes because loss of electronic control always removes pneumatic actuator pressure., The valve remains fixed at its last commanded position until electrical control returns., Intermediate Manifold Pressure rises above 170 pounds per square inch gauge for more than five seconds. What protective response should occur?, The Integrated Air Systems Controller closes both the High Pressure Shutoff Valve and Pressure Regulating Shutoff Valve and generates a BLEED warning., Only the High Pressure Shutoff Valve closes while the Pressure Regulating Shutoff Valve continues regulating the 4th-stage source., The Fan Air Modulating Valve moves fully open while both bleed valves remain available., The Pressure Regulating Shutoff Valve fails mechanically in the open position. Why is this failure treated differently from a normal resettable bleed trip?, The Integrated Air Systems Controller commands the High Pressure Shutoff Valve closed and generates a latched BLEED fault that cannot be reset., The Air Conditioning Accessory Unit automatically transfers bleed control to the opposite engine and inhibits only the affected pressure sensor., The Pressure Regulating Shutoff Valve remains open but is limited to pneumatic regulation until the next power cycle., Bleed-air temperature downstream of the precooler rises to approximately 450 degrees Fahrenheit. What control action occurs before the higher-temperature trip threshold is reached?, The High Pressure Shutoff Valve immediately closes and isolates 10th-stage air regardless of engine operating condition., The Fan Air Modulating Valve closes to reduce fan-air cooling and stabilize the manifold temperature., The Pressure Regulating Shutoff Valve moves toward closed to reduce bleed-air flow in a temperature-topping mode., Wing Anti-Ice is selected ON while the engine bleed precooler system is operating normally. How does this change the precooler temperature-control target?, The normal approximately 415-degree Fahrenheit target is increased to approximately 450 degrees Fahrenheit., The normal approximately 415-degree Fahrenheit target is reduced to approximately 385 degrees Fahrenheit., The Fan Air Modulating Valve is commanded fully open and normal closed-loop temperature regulation is suspended., The primary Air Supply Controller channel becomes inoperative, but backup control remains available. What bleed-air temperature control capability is retained?, The backup circuit controls only the Pressure Regulating Shutoff Valve and allows manifold temperature to rise to 450 degrees Fahrenheit., The backup circuit card controls the Fan Air Modulating Valve to maintain manifold temperature at approximately 380 degrees Fahrenheit., The opposite-side Integrated Air Systems Controller assumes control of both engine bleed systems., The bleed-air isolation valve switch is in AUTO. All pack and engine bleed switches are in their normal ON or AUTO/HIGH positions. What should the isolation valve do, and why?, It closes, dividing the manifold into left and right sections so one duct failure cannot depressurize the entire pneumatic manifold., It opens to equalize pressure between the left and right engine bleed systems during normal cruise., It cycles according to whichever side has the higher Manifold Pressure sensor output., An external pneumatic cart is connected to the ground pneumatic connector. Why must the cart itself control both supplied pressure and temperature?, The ground connector check valve regulates only pressure and has no temperature-control function., The Integrated Air Systems Controller cannot monitor external pneumatic pressure until an engine is running., The aircraft ground pneumatic connection feeds directly into the manifold and provides no pressure or temperature regulation., A pneumatic fault is recorded as a status-level fault rather than a hard fault. What maintenance behaviour distinguishes this from a hard bleed fault?, It generates a Maintenance Awareness System status message and automatic event, but does not require immediate flight-crew action., It immediately closes the Pressure Regulating Shutoff Valve and illuminates the BLEED light until the TRIP RESET switch is pressed., It inhibits the next engine start and can only be accessed through the Onboard Maintenance Function ground-test pages.

ATA 36

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