Radio Altimeter Flashcards
Radio altimeter tells you
Absolute height from the main landing gear
When the main wheels are on the ground it will indicate
0 or sometimes a negative number
How does a radio altimeter work
Transmits a continuous wave at a variable freq
Measures the freq difference
The difference of the freq transmitted to the freq received = time - can use speed = distance/time to find distance
Variable freq of a radio altimeter wave
4200 - 4400 MHz
Radio altimeter indications
Indicates 2,500 to 0
Accuracy of a radio altimeter
With a bank angle it becomes less accurate as it indicates slant range
Normal accuracy = within +- 2ft below 500ft or +- 1.5% whichever is the greater
When does mach no appear on PFD
After mach .5
ISIS
Integrated standby instrument system
Symbol generator
Receives a signal from the EFIS computer and converts it into symbols for the PFD
Flight mode annunciators
Top of the PFD, tells you what the a/c is doing
Different colours and their indications
Green = active mode Red = limitation Amber = caution Blue = sky Brown = ground Magenta = selected parameter/target Cyan = other info
ND displays
Current heading
Track line
Selected heading
Selected course
CRT display
Cathode ray tube
Old type of screen
Poor resolution
LCD display
Liquid crystal display
New type
Decent resolution/bright
Radio altimeter modulation
Freq modulated
