1. Introduction to aircraft systems

Question 1

What are some step changes in improving aircraft efficiency and performance?

Answer 1

Jet engines
Supercritical airfoil, electronic signaling of flight controls
Composites, fly by wire,
Electronic flight instrument System, Trubofan
active controls - sidestick
More electric aircraft

Question 2

What are the 3 major systems of an aircraft?

Answer 2

airframe and structure - provides the lift and control surfaces and the passenger cabin
avionics - represents the brain, providing navigation, communication, autopilot
aricraft systems - provide the means to fly

Question 3

What are the 4 major aspects of for aircraft system design philosophy?

Answer 3

Safety
Handling qulities
Maintenance
Flexibility

Question 4

What are some key philosophies regarding safety?

Answer 4

No Single failure should be catastrophic!
Each catastrophic failure condition must be shown to be extremely unlikely ~10⁻9
Failure will always occur -> evaluation of the consequences is driving factor for design
for a given failure condition the higher the probability of occurence the less critical it should be

Question 5

How can you classify failures?

Answer 5

(1) Failure Conditions with No Safety Effect have no probability requirement.
(2) Minor Failure Conditions may be probable.
(3) Major Failure Conditions must be no more frequent than remote.
(4) Hazardous Failure Conditions must be no more frequent than extremely remote.
(5) Catastrophic Failure Conditions must be extremely improbable

Question 6

What are some safety objectives?

Answer 6

system has to fulfill strict environmental and safety requirements
software designed in multiple languages by multiple teams
each system has a self monitoring function
multi redundancy is necessary
each redundant system allows safe continuation of the operation
automatic backup or seperation in the case of a system failure
the combination of 2 failures should not lead to a loss of a superior system

Question 7

Handling quality objectives?

Answer 7

keep workload for crew as little as possible
instruments and displays using synoptic and visual designs
clear assignment of visual system indication
most switches, displays and signals are applied in flow
master warning panel is visible for all crew members

Question 8

Maintainability objectives?

Answer 8

good accessibility
commonality and replicability between an aircraft and its family
maintainability and reliability are considered major design factors
built in test equipment
manual control and test of the integrity of the protective circuits
spatial seperated maintenance areas for larger -> allows faster inspection..

Question 9

2 maintenance principles

Answer 9

Condition based maintenance
Condition monitoring, Trend monitoring -> predictive maintenance

Question 10

What does flexibility provide?

Answer 10

space for future instruments
power margin +20%, additional instruments are not limited by emergency power
additional wiring capabilities and interfaces