A330 L&B - ATA 29

During troubleshooting of a green system pressure indication fault, maintenance personnel need to inspect the Hydraulic System Monitoring Unit (HSMU) . In which aircraft area is this unit located?. Avionics compartment, electronics rack 800VU. Blue hydraulic compartment, forward belly fairing section. Avionics compartment, electronics rack 600VU.

During cruise flight at high altitude, the ECAM indicates GREEN RESERVOIR LOW LEVEL. The HSMU automatically closes both green FSOVs. Blue and yellow reservoir levels remain normal. No engine fire is detected. According to system logic, what is the expected sequence that follows?. FSOVs reopen after 150 seconds to lubricate EDPs if other reservoirs remain normal. FSOVs remain permanently closed until crew manually resets them in flight. RAT deploys immediately and FSOVs remain closed regardless of other levels.

During RAT manual deployment, which electrical source energizes deploy solenoid 1?. HOT BATTERY BUS supplies release circuit. ESS BUS supplies deployment relay circuit. 115 VAC bus powers actuator motor directly.

During RAT functional inspection, maintenance personnel must positively identify the turbine assembly location prior to deployment testing. Considering both flap track and fairing numbering conventions on the A330, where is the RAT installed?. Right wing, in flap track number four within fairing number three. Right wing, in flap track number three within fairing number four. Left wing, in flap track number four within fairing number three.

While performing a bleed procedure downstream of the engine-driven pump, the technician runs the associated engine and cycles flight controls repeatedly. What is the main technical purpose of cycling control surfaces?. Move trapped air back into reservoir air space for elimination. Increase accumulator pressure to purge nitrogen contamination. Stabilize temperature compensation of the quantity transmitter.

If the green reservoir reaches overheat threshold in a CEO aircraft, which combination of effects is expected?. HSMU triggers FAULT legends for engine and electric pumps. HSMU automatically closes FSOVs and deploys RAT immediately. HSMU depressurizes EDPs without affecting electric pump status.

During an air system check after bleeding, the green reservoir quantity pointer moves more than half of the green arc when comparing pressurized versus non-pressurized readings. What does this indicate?. Excessive residual air remains in system and bleeding must be repeated. Reservoir nitrogen precharge is above specified maintenance limit. Leak measurement valve is not fully closed during test.

During operation, the green hydraulic system pressure begins to decrease gradually due to internal leakage. The pressure transducer installed on the HP manifold continues to send an analog signal to the ECAM, while one of the pressure switches reaches its low-pressure threshold below 1450 psi. What is the correct indication behavior?. ECAM pressure value changes continuously, and amber caution appears when pressure switch threshold is reached. ECAM pressure value remains stable, and amber caution appears when pressure switch threshold is reached. ECAM pressure value freezes at last valid reading and no color change occurs.

During prolonged hydraulic system operation, the green reservoir temperature increases significantly. Although thermal expansion of the hydraulic fluid would normally alter the measured volume, the ECAM quantity indication remains essentially unchanged. What best explains this behavior?. The HSMU applies temperature compensation to the reservoir level signal before transmitting it for indication. The depressurization solenoid de-energizes and the pump remains in pressurized mode delivering system pressure. The FSOV closes automatically and mechanically isolates the pump from the reservoir.

When the green Engine Driven Pump (EDP 1 or EDP 2) P/BSW is selected OFF in flight, assuming no fire condition and normal reservoir level, what is the actual hydraulic consequence for that pump?. The depressurization solenoid energizes and the pump enters depressurized mode without delivering system pressure. The depressurization solenoid de-energizes and the pump remains in pressurized mode delivering system pressure. The FSOV closes automatically and mechanically isolates the pump from the reservoir.

During ground maintenance, the green hydraulic system is depressurized and then repressurized to nominal three thousand (3000) psi. The accumulator nitrogen precharge is found within limits. During rapid and repeated flight control surface movements, only minimal pressure fluctuation is observed. What does this confirm about the accumulator condition?. The accumulator is properly damping transient pressure variations during peak demand. The engine-driven pump is regulating pressure through internal bypass control. The reservoir air pressure is compensating for transient hydraulic loads.

During inspection of a green Engine Driven Pump (EDP), the technician finds that the case drain filter clogging indicator pop-out has activated . The ECAM HYD page shows normal system pressure and there are no hydraulic cautions. What is the most appropriate maintenance action before the aircraft can be considered for dispatch?. Reset or replace the case drain filter and perform operational checks to confirm normal behavior. Defer the condition because normal ECAM pressure confirms correct pump performance. Reset the pop-out indicator only and continue operation with no further actions.

During current monitoring of a green electric pump, the CUDU detects imbalance between at least two phases of the three-phase 115 VAC supply. What is the direct system consequence?. HSMU de-energizes RCCB, pump stops, restart inhibited until ground reset. Pump continues operating in degraded mode with ECAM caution only. HSMU transfers supply automatically to blue electric pump.

During ground maintenance, the blue electric pump is started manually. The 4JC control P/BSW is in the pushed-in position, and the 6JC pulse P/BSW is momentarily pressed to initiate pump operation. After releasing the 6JC pulse pushbutton, the pump continues running normally. What logic maintains the pump in operation?. The HSMU software keeps the control loop closed and the RCCB energized. he HSMU software keeps the control loop open and the RCCB de-energized. The downstream pressure switch maintains RCCB energized while pressure is low.

In flight, both engines fail above 100 knots. Reservoir levels remain normal. According to RAT logic, what sequence is expected?. HSMU energizes deploy solenoid and RAT extends automatically. Crew must manually push RAT MAN ON for deployment. Electric pumps activate before RAT extension is commanded.

During a maintenance functional test of the Ram Air Turbine (RAT), the unit is commanded to stow. The RAT begins retracting and moves upward to approximately ten (10) degrees, but does not continue the retraction cycle and returns to a partially extended position. No hydraulic pressure abnormalities are indicated and no electrical faults are present. What is the most probable cause?. Mechanical linkage misadjustment prevents full mechanical transmission of the stow command. Hydraulic pump output is insufficient to maintain the RAT in deploy position. Automatic airspeed logic commands re-extension before full stow completion.

In flight, the aircraft experiences a green reservoir low level , triggering automatic closure of both green FSOVs. Shortly after, a blue reservoir low level is also detected. According to HSMU logic and system protection philosophy, what is the expected behavior of the green FSOVs?. Green FSOVs remain closed to preserve fluid for RAT-driven system recovery. Green FSOVs reopen automatically after 150 seconds despite blue low level. Blue FSOVs close to protect green hydraulic consumers from depletion.

During takeoff, shortly after liftoff and above 100 knots, one engine fails while the landing gear is still in transit. The green hydraulic system is now powered by only one EDP. The HSMU automatic logic includes the condition “landing gear lever UP” for the green electric pump activation. Why is this condition specifically required?. To ensure gear retraction time remains within normal limits after single engine failure. To guarantee brake accumulator pressure remains stabilized during climb phase. To prevent priority valve isolation of CSM/G during asymmetric thrust condition.

In flight, the green electric pump motor temperature reaches 230°C. The thermal switch closes and the OVHT indication appears on ECAM. After cooling below threshold, what condition prevents immediate restart?. The relay logic remains self-latched until ground reset of 9JV circuit breaker. The HSMU automatically blocks restart until airspeed drops below 100 knots. The pressure switch must detect zero pressure before re-energization.

During operation, the blue electric pump is commanded ON and the downstream pressure switch detects hydraulic pressure below 1450 psi. According to system logic, what is the correct consequence?. Amber FAULT indication appears on ECAM and P/BSW, but pump continues operating. The HSMU opens the RCCB and the pump stops automatically due to low pressure. The green system RAT deploys automatically to restore hydraulic pressure.