Last Updated on 4 years by teboo
021 05 01 00 Aeroplane: primary flight controls
021 05 01 01 Definition and control surfaces
(01) Define a ‘primary flight control’.Used to adjust pitch, roll and yaw.
(02) List the following primary flight control surfaces:
— elevator;
— aileron, roll spoilers, flaperon;
— rudder.
(03) List the various means of control surface actuation including:
— manual;
— fully powered (irreversible);
— partially powered (reversible).
021 05 01 02 Manual controls
(01) Explain the basic principle of a fully manual control system.Direct, mechanical connection from the flight controls to the control surfaces.
021 05 01 03 Fully powered controls (irreversible)
(01) Explain the basic principle of a fully powered control system.No direct link to the control surfaces. Control is lost if hydraulic power is lost.
(02) Explain the concept of irreversibility in a flight control system.Usually the controls are hydraulically locked so cannot be moved without power, indirect control. Usually refers to the primary flight controls.
(03) Explain the need for a ‘feel system’ in a fully powered control system.Because the pilot has no feedback from the controls it needs to be synthesised so the pilot can gauge the aerodynamic forces experienced by the surface.
(04) Explain the operating principle of a stabiliser trim system in a fully powered control system.An aircraft can experience large movements in CofG in different phases of flight therefore the trim needs to be adjustable. Surface deflection creates drag so the entire horizontal stabiliser can be adjusted to each stage of flight. It is a very powerful control so can be tricky if it fails.
(05) Explain the operating principle of rudder and aileron trim in a fully powered control system.Same principle.
021 05 01 04 Partially powered controls (reversible)
(01) Explain the basic principle of a partially powered control system.The controls are linked directly to the surface but are assisted by hydraulics.
(02) Explain why a ‘feel system’ is not necessary in a partially powered control system.Because the surfaces are directly connected there is already real feel.
021 05 01 05 System components, design, operation, indications and warnings, degraded modes of operation, jamming
(01) List and describe the function of the following components of a flight control system:
— actuators;
Convert hydraulic pressure into physical movement.
— control valves;Selects the direction of hydraulic flow.
— cables;Control cables…
— electrical wiring;Um…
— control surface position sensors.So that the actual position of the surface can be verified.
(02) Explain how redundancy is obtained in primary flight control systems of large transport aeroplanes.By doubling key components such as actuators.
(03) Explain the danger of control jamming and the means of retaining sufficient control capability.As the range of deflection of certain surfaces is large jamming can be a problem if the trim fails when at an extreme setting for example.
(04) Explain the methods of locking the controls on the ground and describe ‘gust or control lock’ warnings.These can be physical in the case of reversible controls. These locks are made to be very obvious to prevent carnage in the air.
(05) Explain the concept of a rudder deflection limitation (rudder limiter) system and the various means of implementation (rudder ratio changer, variable stops, blow-back).A rudder limiter prevents large deflections at high speed to prevent damage. rudder ratio changer limits travel, variable stops, I think are where the rudder is split into different sized surfaces with their own movement limits. A blow back system acts like a torque wrench in that at a certain force it slips like a clutch.
021 05 02 00 Aeroplane: secondary flight controls
021 05 02 01 System components, design, operation, degraded modes of operation, indications and warnings
(01) Define a ‘secondary flight control’.Flaps, leading edge devices, spoilers, speed brakes etc. Anything that doesn’t direct affect pitch roll and yaw.
(02) List the following secondary flight control surfaces:
— lift-augmentation devices (flaps and slats);
— speed brakes;
— flight and ground spoilers;
— trimming devices such as trim tabs, trimmable horizontal stabiliser.
(03) Describe secondary flight control actuation methods and sources of actuating power.Mechanical for light aircraft, large aircraft are hydraulically or electrical controls and move through tracks or by screw jacks.
(04) Explain the function of a mechanical lock when using hydraulic motors driving a screw jack.To lock it in place.
(05) Describe the requirement for limiting flight speeds for the various secondary flight control surfaces.The same as anything, bits and pieces have their operating limits.
(06) For lift-augmentation devices, explain the load-limiting (relief) protection devices and the functioning of an auto-retraction system.Automatic or manual.
(07) Explain how a flap/slat asymmetry protection device functions, and describe the implications of a flap/slat asymmetry situation.Implications are obvious and sensors detect any asymmetrical behaviour.
(08) Describe the function of an auto-slat system.Operate in conjunction with the trailing edge flaps. Can auto retract if a stall is imminent.
(09) Explain the concept of control surface blow-back (aerodynamic forces overruling hydraulic forces).Well well…
021 05 04 00 Aeroplane: fly-by-wire (FBW) control systems
021 05 04 01 Composition, explanation of operation, modes of operation
(01) Explain that an FBW flight control system is composed of the following:
— pilot’s input command (control column/sidestick/rudder pedals);
— electrical signalling paths, including:
• pilot input to computer;
• computer to flight control surfaces;
• feedback from aircraft response to computer;
— flight control computers;
— actuators;
— flight control surfaces.
(02) State the advantages and disadvantages of an FBW system in comparison with a conventional flight control system including:
— weight;
— pilot workload;
— flight-envelope protection.Advantages obvious, disadvantages are sensor or software failure leaving the pilots with no direct control.
(03) Explain why an FBW system is always irreversible.Because there is no mechanical link to the controls.
(04) Explain the different modes of operation:
— normal operation (e.g. normal law or normal mode);
Fully operational, low pilot workload.
— downgraded operation (e.g. alternate law or secondary mode);Some modes or features absent.
— direct law.Simple connection between pilot and controls – higher workload.
(05) Describe the implications of mode degradation in relation to pilot workload and flight-envelope protection.As protection is reduced a pilot has to pay more attention and also know which features are no longer available.
(06) Describe the implications for pilot workload during flight in normal operation (normal law/normal mode) during the following scenarios:
— an undetected system error activates the envelope protection;
The a/c probably has a better idea than you do, so being wary of overriding. This results in a higher workload.
— aircraft departs from intended flight path;Put it back ASAP!
— aircraft does not respond as expected to control inputs.Again higher workload, I’m not sure what answer they want here.
(07) For aircraft using sidestick for manual control, describe the implications of:
— dual control input made by the pilot;
Side stick is control summing.
— the control takeover facility available to the pilot.Priority is selectable.
(08) Describe solutions or actions to regain control.Being unambiguous in who has control of the aircraft.
