Avionic systems Flashcards
What are the benefits of achieving safe two crew operations
savings in:
- salaries
- expenses
- training
- weight
Name 5 drivers for avionic systems
- improved safety
- all weather operations
- reduction in fuel consumption
- improved aircraft performance, control and handling
- reduction in maintenance costs
Data bus:
systems interfacing directly with the pilot
- displays
- communications
- data entry & control
- flight control system
Data bus:
Aircraft state sensors
- air data systems
- inertial sensors
Data bus:
Navigation
- radio navigation
- DR navigation systems
Data bus:
External world sensors
- Infrared sensors
- Radar
Data bus:
Task automation
- house keeping mgt.
- navigation systems mgt.
- autopilot & FMS
- engine control & mgt.
Name three types of displays
- head down display (HDDs)
- head up displays (HUDs): project information in pilot’s field of view
- helmet mounted displays (HMDs): they are HUDs on the helmet
How is long range communication accomplished
Provided by high frequency (HF) radios, operating the band 2-30 MHz
How is medium range communication accomplished
Civil:
Provided by very high frequency (VHF) radios, operating the band 30-100 MHz
Military:
Provided by ultra high frequency (UHF) radios, operating the band 250-400 MHz
What communication system can be found in modern aircraft
Satellite communications (SATCOM) systems, providing reliable world-wide communication
What is ‘data entry and control’ used for
- enables the crew to interact with the avionic systems
Name systems found under ‘data entry and control’
- keyboards
- touch panels
- direct voice input (DVI) control
What two areas of flight control use electronic systems
- auto stabilisation systems
- fly-by-wire control system
list air data quantities required for control systems
- altitude
- calibrated air speed
- vertical speed
- true air speed
- Mach number
- air stream incidence angle
what measurements are needed to calculated the required air data quantities
- static pressure
- total pressure
- air temperature
why is the aircraft attitude and heading important
- for executing manoeuvres
- flying in poor weather conditions
- several avionic systems relies on it: autopilot, navigations, weapons aiming
How is attitude of an aircraft measured
- using gyros and accelerometers
- usually a body mounted (strap-down) configuration
- computer analysis this data and produces figures/display
Equation for gyroscopic precession
T = dH/dt = H˙θ
H = angular momentum = IxWr I = moment if inertia about spin axis
What are Dead reckoning navigation systems
- derive present position by estimating the distance travelled from a known position
- independent of everything
- are updated from position fixes
Name three types of dead reckoning navigation systems
- inertial navigation systems
- Dopller/heading reference systems
- air data/heading reference systems
How do radio navigation systems work
- based on satellite or ground based transmitters
- computer used to derive position from signals transmitted
i. e. GPS
What navigation systems aid in bearings during flight
- VOR/DME and TACAN from ground beacon radio transmitters of main air routes
What navigation systems help with landing approach
Instrument and microwave landing systems
When is it useful to have landing approach navigational aids
in poor weather conditions
How many satellites in GPS nominal constellation
24
Name an external world sensor system on an aircraft
weather radar, measuring water droplets in air
What does the navigation management system do
- combines all data from navigation sources (GPS,DR) and proves best estimate of aircraft position, ground speed etc.
What are basic modes of autopilot
- height hold and heading hold functions
- more sophisticated autopilot aids in landing during poor weather conditions
What does the flight management system do
- flight planning
- navigation management
- engine control
- control of aircraft flight path
- control of vertical flight profile
- 4D navigation
- minimising fuel consumption
(allows for 2 person crew)
What does the engine control and management do
- ensures engine responds to throttle commands in an optimum manner
- ensures the engine limits in terms of temp, speed, acceleration are not exceeded
What do engine health monitoring systems measure
- performance deterioration
- excessive wear
- fatigue damage
- high vibration levels
What does the house keeping management do
Covers the automation of background tasks
- fuel management
- electrical power supply system management
- hydraulic power supply system management
- cabin pressurisation and environmental systems
- warning systems
- maintenance and monitoring systems
