In classical aircraft engineering, an aircraft is subdivided in which three groups?
airframe, engine and systems
What are the three system groups of an A/C?
Structure, vehicle system, avionic system
What is the function of the airframe?
- complex and integrated set of structural components
- supports the mass of systems and PAX
- carries loads and stresses
- also known as the “platform”
What is the function of the vehicle system?
- also known as general or utility system
- enables the A/C to fly safely
- provides an adequate environment for crew and PAX
What is the function of the avionic system?
provides information, control and communication functions that enable the aircraft to fulfil its operational role
What is the Flight control system?
- nowadays usually a Fly-by-Wire (FBW) system
- pilot control input is elaborated on the basis of air data, A/C attitude etc. to issue the proper control surface deflections that will effect the desired aircraft motion
What is the Engine control system?
in most recent aircraft a Full Authority Digital Engine Control (FADEC) system
What is the Air data system?
provides airspeed, altitude, air temperature, rate of climb or descent information
What is the Attitude system?
provides information on pitch, yaw and roll angles, rates and accelerations
What is the Electrical system?
provides electrical power for flight and engine control computers, air data system, attitude systems, hydraulic servo-valves and (on some A/C) electrically driven hydraulic pumps
What is the Hydraulic system?
provides motive power for the actuators that move the flight control surfaces, or the engine thrust reversers
What are essential functions?
The functions whose loss would reduce the capability of the A/C or its crew to cope with adverse operating and environmental conditions (i.e. loss of cabin pressurization or loss of the anti-icing system)
What are critical functions?
Functions which could cause the loss of the aircraft or fatal injuries to the occupants (i.e. a complete loss of engine power)
How does the severity of a failure condition relate to its probability?
The severity of a failure condition must be inversely proportional to ist probability
What must be considered to evaluate the severity of a failure condition?
- Effects on the airplane
- Effects on the crew members
- Effects on the occupants