Question 1
Question
Select the correct response(s):
Answer
-
Water hammer is negligible in hydraulic system pipe installation.
-
Water hammer is an important parameters which used to dimensionate pipes.
-
Hydraulic Pumps generally used in aircraft hydraulic systems are gear type and capable to
provide roughly same pressure at any flow demand (if below specified max flow demand).
-
Hydraulic Pumps generally used in aircraft hydraulic systems are piston type and capable to
provide roughly same pressure at any flow demand (if below specified max flow demand).
-
Acceleration of fluid is not negligible for the calculation of the necessary pressure of hydraulic pressurized reservoirs.
Question 2
Question
If the aircraft hydraulic system supply the services that control the direction of the aircraft on the ground (e.g. nosewheel steering and differential braking):
Answer
-
, the emergency braking system must have differential control.
-
, consideration shall be given to supplying the nosewheel steering and normal brakes from different hydraulic systems.
Question 3
Question
Common use Aerospace Hydraulic Pumps:
Answer
-
when engine driven, are installed in engine gearbox. Its suction line and fire shut-off valve in suction line are fire proof tested
-
when engine driven, are installed in engine gearbox. Its suction line is fire resistant (5 min) and fire shut-off valve in suction line is fire proof tested (15 min).
Question 4
Question
Common use Hydraulic Reservoirs :
Answer
-
Do not need pressurization. Vented type reservoir is sufficient whenever located above the pump.
-
Utilizes the system pressure, acting on a differential piston, to achieve the required tank pressure.
-
The pressure required in the reservoir to supply fluid to the pump should be calculated using the guidelines in AIR1922.
-
This pressure must be sufficient to avoid pump cavitation at Pcrit.
-
Each reservoir should be equipped with pressure regulating valves and a filter.
-
No Hydraulic Reservoirs shall be located in a designated fire zone.
Question 5
Question
CFG main advantages compared with VFG are:
Answer
-
Better reliability.
-
Simpler
-
Cheaper.
-
Less volume and weight for for the same power delivered.
-
Several suppliers able to design and produce them.
-
Fixed output frequency, with fixed efficiency and capability.
-
No overvoltage event potentially leading to common failures.
Question 6
Question
The emergency system shall power the services necessary to complete a flight and make a safe landing. The services to be powered must include:
Answer
-
Those required for descent, approach and Landing.
-
Those required for immediate safety
-
Those required for continued controlled flight
Question 7
Question
New high voltage levels (270 Vdc and 230 Vac) are applicable to civil and military electrical systems since they permit to:
Answer
-
Increase hydraulic Systems.
-
Increase Electric Systems.
-
Increase Pneumatic Systems.
-
Increase Mechanical Systems.
-
Reduce electrical power demand.
-
Decrease the losses in the feeders and distribution wiring.
Question 8
Question
Electrical power quality is determined by:
Question 9
Question
Li-Ion battery technology main advantages compared with Ni-Cd one are:
Answer
-
Less susceptible to abuse conditions.
-
Less weight for the same power delivered.
-
Maintenance free and higher service life. This, plus the improved reliability, leads to an important Direct Maintenance Cost (DMC) reduction.
-
Better control of the SOC. No memory effect.
-
No mounting restrictions
Question 10
Question
LED technology main advantages compared with HID one are:
Question 11
Question
What of the following exterior lights have their illumination performances covered by the EASA Part 25 requirements?
Question 12
Question
The biggest problem in humans associated to exposure at high altitudes is:
Question 13
Question
Aerodynamic heating is given, basically, by the total temperature of the air computed as follows Ttot = Tambient (1+ 0.2 Mach2). Given an ISA atmosphere, the heating is maximum in one of the following conditions:
Answer
-
40 kft, Mach=0.8.
-
SL, Mach=0.4.
Question 14
Question
Minimum standard ventilation to maintain CO2 levels in enclosed spaces is (at SL, 15ºC) according to ASHRAE:
Answer
-
1.5 kg/min of air.
-
1 kg/min of air.
-
0.5 kg/min of air.
Question 15
Question
Being one of the most efficient cooling systems, why liquid cooling is not so used:
Answer
-
Cost.
-
Temperature range.
-
Weight.
-
Efficiency.
-
Complexity
Question 16
Question
Redundancy in cabin pressurization outflow valves is requested:
Answer
-
Sometimes.
-
Never.
-
Always.
Question 17
Question
In a wing profile section, ice accretion impingement limits will be most extended in the following case:
Answer
-
Thick profile, low speed, small droplets.
-
Thin profile, low speed, big droplets.
-
Thin profile, high speed, big droplets.
Question 18
Question
A deicing system is basically sized to limit quantity of ice accreted. What is the worst flying condition in terms of design:
Answer
-
Low speed, high Outside Ambient Temperature.
-
Low speed, low Outside Ambient Temperature
-
High speed, high Outside Ambient Temperature
-
High speed, low Outside Ambient Temperature
Question 19
Question
Which are the aircraft key operational cases that are normally considered for the sizing of the APU on large civil aircrafts for passenger transport?
Answer
-
Main Engine Start In Flight at 30 kFt.
-
On Ground Electrical power demands only.
-
On Ground Electrical & Pneumatic power demands from the A/C systems
Question 20
Question
The APU model PW980 in the AIRBUS A380 is steadily supplying bleed air for the aircraft pneumatic systems (MES or ECS) on ground. In a matter of a couple of seconds, such demand is significantly reduced. What would be the expected immediate reaction from the APU control system?
Answer
-
The ECB commands the Bleed Valve to close and the APU electrical generator to absorb more shaft power in order to avoid a Load Compressor over speed.
-
To command the opening of the Anti-surge Valve and the closure of the Inlet Guide Vanes, to alleviate the bleed pressure raise & reduce the bleed airflow supply.
-
The command to the aircraft’s fuel system to shut off completely the fuel supply to the APU and stop it to prevent the burst of the aircraft’s bleed piping.
Question 21
Question
The APU model PW980 in the AIRBUS A380 is steadily supplying bleed air for the aircraft pneumatic systems (ECS) on ground. In a matter of a couple of seconds , such demand signal from the ECS is significantly reduced . Which of these cannot be a normal reaction of the APU Ctrl system under such situation:
Answer
-
To keep fully open the Bleed Shut-off Valve while correspondingly closing the Load Compressor IGVs.
-
To automatically shut down the APU in case an oil system overtemperature is sensed by the APU ECB.
-
To correspondingly close the Load Compressor IGVs to reduce the bleed flow, while keeping constant the fuel flow to maintain a constant L/C speed.
-
To keep the Surge Valve fully closed while progressively reducing the fuel flow to avoid an APU rotors overspeed condition potentially leading to a rotor burst.
Question 22
Question
For the start of the APU engine on large civil aircrafts for passenger transport, the most commonly used system consists on:
Answer
-
An electrical 12VDC Starter/Generator.
-
An electrical 28VDC Starter/Generator.
-
An electrical 28VDC Starter Motor.
-
An air turbine starter.
Question 23
Question
Which of the following is not a true statement related to APU in-flight start reliability :
Answer
-
The A350 flight test campaign (Honeywell HGT1700) is already showing in 2013, APU in- flight restart reliabilities of around 98%.
-
The A330 fleet (Honeywell 331-350 APU) has already shown APU in-flight restart reliabilities of 97%or higher.
-
The APU shall be operative without permanent presence of operator.
-
The APU in its installed configuration shall have an adequate in- flight start reliability (not less than 95%) throughout the flight envelope taking account of all approved fuel types and temperatures
-
The APU in its installed configuration shall have an adequate in- flight start reliability (not less than 83%) throughout the flight envelope taking account of all approved fuel types and temperatures
-
The APU shall be capable to pressurize the aircraft and maintain an adequate cockpit and cabin environment in one-engine inoperative cruise conditions, taking into account one engine operative requirements, up to 30,000 ft.
-
The A350 shall be capable to start any engines - regardless of engine starting sequence or engine type (RR or GE) - on ground using battery power supply.
Question 24
Question
Which of the following statements is/are not correct? :
Answer
-
Same as in a propulsive power plant, the APU shall be installed in a Fire Compartment.
-
The APU engine shall be mounted on the A/C structure with a Suspension System designed
to withstand the corresponding inertial loads.
-
The APU Air Intake usually has an electrically actuated flap door that is kept closed while the APU is not operating.
-
The Exhaust Muffler outlet at the very rear end point of the fuselage is the most favorable location for its pressure effect for in-flight APU starts
-
The Cooling Inlet function is to convey the necessary atmospheric air flow into the APU for both the : Power Unit and Load Compressor
Question 25
Question
The installation of the APU in the fuselage tailcone section on large civil aircrafts for passenger transport, presents as a significant drawback:
Answer
-
The impacts on the aircraft in case of rotor burst.
-
The noise projection on the ground.
-
The in-flight aerodynamic conditions.
-
The accessibility for ground maintenance operations
Question 26
Question
The installation of the APU in the fuselage section 19.1 on AIRBUS’s large civil aircrafts for passenger transport, presents a main advantage (when compared to an APU installed in the wing root or main landing gear zones), that is:
Answer
-
The length of fuel supply line, bleed air pipe & electrical cables lengths.
-
Maintenance tasks and APU replacement are easier.
-
The noise projection on the ground.
Question 27
Question
Which one is not a key feature for the fire protection design strategy in an typical APS installation? :
Answer
-
An adequate APU compartment drainage system.
-
A manual (non-automatic) APU fire detection & extinguishing system for APU ground use.
-
The use of fireproof titanium firewalls of 0.4 mm thickness.
-
The installation of the APU in a fire compartment with a fire detection & extinguishing system.
Question 28
Question
Which are the key features for the fire protection design strategy in an typical APS installation?
Answer
-
The fire detection & fire extinguishing systems only.
-
The installation of the APU in the fuselage tailcone area, and the limitation of the APU use
mostly for ground.
-
The fireproof design of the APU compartment & components, the ventilation, the drainage, and the fire detection & fire extinguishing systems.
Question 29
Question
The primary step for the Certification of the APU system in the aircraft is:
Answer
-
To achieve the certification of the aircraft electrical & pneumatic systems to be supplied by the APU.
-
To achieve the APU Qualification obtained by the manufacturer for the engine by TSO C77B.
-
The Compatibility & the Flight Test campaigns.
Question 30
Question
Which is the primary test platform for certification of the integrated A/C & APU system? :
Answer
-
The APU engine test cells
-
The Flight Tests aircrafts
-
The Compatibility Tests rig.
-
The Icing Tests rig
Question 31
Question
The normal duration of the development cycle for a new APU system in a large transport aircraft is:
Question 32
Question
Which are the aircraft key operational cases that are normally considered for the sizing of the APU on large civil aircrafts for passenger transport? :
Answer
-
On Ground Electrical & Pneumatic power demands from the A/C systems
-
In-Flight Electrical power demands
-
Main engine start in flight at 22Kft
Question 33
Question
The APU is steadily operating on Max ECS supply condition on ground. Due to an incorrect tightening of the clamp that couples the APU Bleed Valve and the ATA36 pneumatic duct, an air leak takes place in fuselage section 19.1. Which of these statements is correct at that instant? :
Answer
-
The Surge Control Valve ( SCV ) will be commanded to ‘close’ since the L/C operating condition reaches the cracking line.
-
The L/C IGVs control logic will command the closing of the SCV to further increase the flow towards the ECS.
-
The APU lubrication system heat exchanger will remain air cooled by airflow pumped by the APU exhaust eductor or a gearbox driven fan.
-
The APU Inlet door position regulated by the ECB will be further opened to increase the airflow through the APU Load Compressor.
-
The surge control logic will command the closing of the SCV to further increase the flow towards the ECS.
Question 34
Question
Which of the following functions correspond to the FCS?
Answer
-
Stability augmentation
-
Thrust setting
-
Positions aerodynamic control surfaces according to pilot, autopilot or stability augmentation inputs
-
Provides the pilot with the required force feedback
-
Flight Envelope Protection
-
Load alleviation (manoeuvre and gust).
-
Flutter suppression.
-
Thrust vectoring.
-
Abnormal position recovery, including post stall
Question 35
Question
Two of the following statements are correct. Which ones are they?
Answer
-
Artificial feel systems are required to provide good handling qualities in irreversible FCS systems
-
In an “irreversible” FCS, pilot cannot reconfigure the system after a failure.
-
In an irreversible FCS aerodynamic loads are not fed back to the pilot inceptor
Question 36
Question
Identify two drawbacks of the Fly By Wire systems in the list below.
Answer
-
They require the use of hydraulic systems to provide power to the actuators.
-
They require a high degree of redundancy.
-
High development cost and high system clearance effort.
-
SW development complexity and inherent computing delays.
-
Safety critical SW certified against Common Mode Failures (testing +
specification).
-
EMI susceptibility
-
Evolving regulation.
Question 37
Question
Which of the following statements are true for all types of Fly By Wire FCS:
Answer
-
A mechanical back-up system is required to control the aircraft after a total FBW system failure.
-
Configuration changes are easy to implement in comparison with mechanically signaled FCS.
-
May be Active control technology (ACT) or Control configured vehicle (CCV)
-
Direct mechanical link are replaced by an electrical signalling system
-
Pilot control aircraft dynamics parameters instead of aircraft surface position
-
Improve aircraft natural dynamic behaviour
-
Cockpit layout design flexibility
-
Reduced maintenance and operational cost
-
Reduced weight, increased reliability
Question 38
Question
Which of the following statements do not apply to the concept of Control Configured Vehicles:
Answer
-
Requires a careful balance between stick force and control authority at low and high speed.
-
Provides automatic prevention of stall departure and spinning.
-
Concurrent and complementary design of the basic airframe together with FCS to achieve performance improvements.
-
Allows improved aircraft performance and manoeuvrability.
-
Automatic structural protection and gust alleviation enhancing safety and reduce pilot’s workload.
-
Require full authority FCS with aircraft response feedback.
-
Use of the FCS to actively compensate for deficiencies in the aerodynamics of the basic airframe.
Question 39
Question
What is the main disadvantage of the Electro Mechanical Actuator for its application in Primary FCS?
Answer
-
If there is a mechanical jamming, control surface remains in the last commanded position.
-
The mechanical signaling circuit is prone to jamming.
Question 40
Question
Identify two inputs to the FCS design from the following list:
Answer
-
Interface Documents.
-
Compliance Check List.
-
Maintenance concept
-
Technical Direction (Compatibility with A/C Concept and other systems and Target Cost)
-
Preliminary Design (Control Surface Definition, Space Envelope, Target Weight)
-
Flight Physics (Functional def., Suf. deflexion, Actuation rate, Trim charact./artificial feel, Failures criticality)
-
Loads (Hinge moment and Surface deflexion limits)
-
Regulation (Certification basis and Safety criteria)
-
Reliability (Failure rate target)
-
Maintenance (Maintenance Concept and Failure detection level)
Question 41
Question
Identify why kerosene type fuels (Jet A-1/JP-8) are safer than wide-cut fuel types (JetA/JP-4) (choose one):
Answer
-
Kerosene Type Fuels have higher freezing temperature.
-
Density of Kerosene Type Fuels is higher.
-
Kerosene Type Fuels is less flammable than Wide-Cut Fuel Types
-
Kerosene Type Fuels have lower volatility / Vapor Pressure than Wide- Cut Fuel Types.
Question 42
Question
Identify what is the purpose of the fuel vent subsystem (choose two):
Answer
-
Allow fuel thermal expansion inside the tanks without external leakage.
-
Maintain the fuel tank temperature.
-
Avoid fuel tank overpressure or under-pressure during climbs and dives.
Question 43
Question
For certification of the fuel system is essential to demonstrate that (choose one):
Answer
-
The fuel reserves are higher than 5% of the fuel tank contents.
-
The aircraft can be refueled in flight.
-
The fuel supply of the engines is maintained across all the flight envelope
Question 44
Question
What are the advantages of the Boom/Receptacle Air Refuelling Systems compared with probe and drogue Air Refueling System systems (choose two):
Answer
-
It allows simultaneous air refuelling of two receiver aircraft.
-
Reduces the receiver pilot work load when in contact.
-
None, they are fully compatible between them.
-
Allows reverse refuelling
.
-
Possibility to refuel aircrafts with probe.
-
Higher flow rates and then less time to complete
refueling.
-
A tanker with flying boom can be adapted with a probe-adapter
Question 45
Question
What are the advantages of the Probe and Drogue Air Refuelling Systems compared with Boom/Receptacle Air Refueling System systems (choose three):
Answer
-
It would allow simultaneous air refuelling of two receiver aircraft.
-
Normally minimizes the modification of the aircraft and fuel system due to the Air Refueling
Installation
-
None, they are fully compatible between them.
-
Simpler and cheaper design.
-
Allows A/Cs not originally designed as tanker to be converted.
-
Allows higher fuel transfer flow rates minimizing the time in contact.
-
No BOOM operator is needed.
-
Can be used to refuel helicopters.
Question 46
Question
In terms of safety, which is the main concern in air refuelling operations?
Answer
-
Transferring fuel is always the big safety concern.
-
Lack of fuel transfer in flight will not allow the receiver to make a safe landing.
-
AAR operations requires two aircraft flying in close formation.
In addition to the danger of flying in close formation, there are risks associated with the dispense devices.
-
Coupling detached & Uncontrolled hose movement.
-
Requires two aircraft flying in close formation
-
Several aircraft are flying in close proximity, increasing the pilot workload and hence the risk of collision.
-
In addition to the danger of flying in close formation, there are risks associated with the dispense devices.
Question 47
Question
The purpose of fire detection systems is:
Answer
-
To eliminate the possibility of a fire in the aircraft
-
To sense and indicate the presence of overheat, smoke or fire
-
To signal presence and locate fire in the aircraft
-
To extinguish the fire in the aircraft.
Question 48
Question
Why current fire extinguishing substances (Halon based) have to be replaced in the future? (choose one)
Answer
-
They are considered risk substances for human health.
-
Density of halon is too high compared with new substances considered equivalent for fire
extinguishing.
-
When used, or escape to the atmosphere, they are substances that contribute to destroy the ozone layer of the upper atmosphere.
-
The Montreal Protocol of 1987 identified Halon 1301 and Halon 1211 as two of a number of halogenated agents requiring limitations of use and production.
Question 49
Question
What is the purpose of the self sealing fuel tanks? (choose one)
Answer
-
The avoid fuel tank explosion sealing the tank after projectile impact.
-
They reduce the risk of fire in hot areas around the fuel tanks by minimizing fuel leakage in case of a thread impact
-
To conserve inerting performances by keeping the tank sealed.
Question 50
Question
What are the two main factors to be considered in the selection of foams?
Question 51
Question
What are the differences today between OBIGGS for civil airliners and OBIGGS for military airplane (choose two)
Answer
-
Civil ones are more demanding than military one.
-
There is not any difference.
-
Military: The objective is to reduce vulnerability and enhance the ability to survive enemy fire into a possibly explosive fuel tank.
-
Civil: Active protection on center wing or body style tanks reasons of being unused by operators and are prone to be heated due to the usual closeness of heat sources like the air conditioning packs.
-
The purpose of civil ones is to minimize the risk of tank explosion in case of fuel system failures and military ones is to minimize the risk of tank explosion in case of external military threats.
-
For military application Limiting Oxygen Concentration LOC =9% and civil LOC=12%.
Question 52
Question
Ground testing allows:
Answer
-
Test individual elements .
-
Test all aspects of the complete a/c and of the man/machine interface.
-
Modeling, simulation, individual elements or the complete a/c are tested as far as possible to find design deviations as soon as possible.
Question 53
Question
Identify what tests are performed during pre-flight test phase:
Answer
-
Structural loads tests .
-
Functional tests
-
Taxi tests.
-
Wind Tunnel tests
-
Simulation tests.
-
Ground vibration tests.
-
Gain margin tests.
-
Weight & Balance.
-
Propulsion tests.
Question 54
Question
The Nose Wheel arrangement of an airplane is shown in attached figure:
Answer
-
Statically neutral, Dynamically neutral suitable only for steered mounting and shimmy damper required.
-
Statically neutral, Dynamically stable, Stable in reverse when wheel casters right around, Normally Shimmy damper required unless twin wheels coupled in rotation used.
-
Statically unstable. Dynamically Stable. Unstable in reverse. Must be locked or steered.
Question 55
Question
Brake by wire system control typically has critical partitions as:
Answer
-
Brake by wire systems do not use brake order computer control. The command is mechanically transmitted by to the Brake Valve. Only Antiskid computer is used to carry on antiskid function.
-
Beside non-commanded brake order generated from computer caused by SW error or HW failure at take-off, brake availability at landing could also be critical. A back up brake control (emergency system) torque limited (without antiskid protection) is normally needed.
Question 56
Question
For aircraft designs required to operate in unpaved airfields:
Answer
-
Radial tyres are normally used because they are lighter than Bias Tyres.
-
Bias tyres are normally used because sidewall thickness and better retreadability. Sidewall thickness contributes to minimize punches when operating underinflated when sidewall is
more exposed to ground contamination
Question 57
Question
Which are the key features of the Solid State Power Controller?
Answer
-
Electronic component based on power semiconductors
-
Mechanical trip device activated by the heating
-
Protects
installations from short circuits and overloads.
-
Remote control/monitor capability
-
High Mean Time Between Failure-MTBF.
-
Is a wiring protection device as circuit breaker (CB), Arc Fault Circuit Breakers (AFCB), Remote Controlled Circuit Breakers (RCCB).
Question 58
Question
The purpose of electrical distribution systems is:
Answer
-
Ensure a maximum availability of the bus-bars.
-
Mechanical disconnection (mechanically disconnect it from the engine).
-
Participate in the connection/disconnection of the power sources.
-
Ensure the electrical network reconfigurations.
-
Ensure the protection against short circuit, over voltage, …
-
Ensure the electrical protections in order to avoid power source paralleling (AC) and propagation of defaults.
Question 59
Question
Identify two drawbacks of the conventional protection devices (fuse and Circuit breakers):
Answer
-
They require a high volume.
-
They are general use devices.
-
Influenced by ambient temperature.
-
No monitor capability.
-
Complex to monitor.
-
Slow response.
-
No reset capability.
-
No arc-fault detection capability.
Question 60
Question
What type of main generator disconnection could perform crew with cockpit push-buttons?
Question 61
Question
Regulated converters advantages compared with unregulated converters are:
Question 62
Question
Why large aircrafts generally use Hydraulic Powered Actuation Systems?
Answer
-
High hydro-mechanical stiffness and associated high frequency response is relevant for flight control actuation. Additional typical factors are good response time, efficiency, reliability and robustness of hydro-mechanical systems when compared with another systems.
-
High hydro-mechanical stiffness and associated high frequency response is relevant for flight control actuation. Additional typical factors are response time and efficiency but not reliability and robustness, when compared with another Systems
-
High Power Transmission vs. System Weight.
-
High Efficiency.
-
Robustness & Reliable.
-
Shared Power Generation System.
Question 63
Question
Generally, with regards to the number of hydraulic systems used in a civil typecertified large aircraft under Part 25 – EASA Airworthiness Regulations:
Answer
-
The use of EHAs or EMAs for PFC may allow using only two hydraulic systems. This is dependent on having sufficient redundancy within the electrical power generation system.
-
If there are a large number of services that are powered hydraulically, four independent hydraulic systems may be a design solution in order to reduce the size of pumps.
-
There is no any aircraft using two hydraulic systems. If any primary flight control is required to be hydraulically powered, definitively three hydraulic systems are required.
-
Large aircrafts with two engines and three hydraulic systems normally requires a PTU (Power Transfer Unit) to transfer hydraulic power between the hydraulic systems in determined failure cases or for ground taxing with one engine shut down.
Question 64
Question
Indicate which of the following statement(s) regarding the FCS is (are) correct:
Answer
-
In a “direct link” FCS, there is a linear relation between control surface displacement and stick forces.
-
In a “fly by wire” FCS, pilot controls parameters rather than surface position.
-
Artificial feel systems are required to provide good handling qualities in irreversible FCS systems
-
In an “irreversible” FCS, pilot cannot reconfigure the system after a failure.