Systems and electrical power Flashcards
System
“any dynamically functioning organisation of man made devices”(Jane’s 1986)
Power systems
systems dedicated to producing a source of power for use on the aircraft
User systems
systems using power from one or more power systems on the aircraft
Aircraft power systems summary
schematic
System design influences
function-operation
power requirements
mass and space
installation
vulnerability
maintenance
safety
adaptability
cost
Types of system control aspects
open-loop
closed-loop authority
limited authority
full authority
Open-loop(+/-)
Positive
relatively simple system
low cost
Negative
operator intensive
e.g. car steering, light aircraft control
Closed-loop principle
closed-loop control system requires a feedback loop to control the system operator
output system compared to the input reference
mathematic error produced until the output matches the input requirement
Closed loop(+/-)
Positive
reduced operator workload
stabilises unstable systems
Negative
more complex system-reliability issues
more maintenance
higher cost
Authority
“The extent to which the functioning system is allowed to control itself and other systems”
Limited authority
e.g. engine temperature control, vehicle speed control
Full authority
e.g. FBW system, FADEC
Full authority management system
Safety concepts
Redundancy
Fail-safe
Fail tolerant
Redundancy
over capacity via back up systems to provide alternative systems in the event of failure
Fail safe
systems designed to fail ‘into a safe mode’ which reduces the possibility of a critical situation developing
Fail tolerant
system designed to operate, possibly at a reduced level, when certain components or sub systems fail
