nav exam prep 3 Flashcards
Types of the radar in NZ
secondary and primary
primary radar
works on echo principle, signals sent from ground-based radar aerial strike an aircraft and are scattered in many directions and some of which return to the radar aerial
secondary radar
the signal sent from the ground-based radar aerial are received by a/c transponder which instantly sends a response signal back to the radar installation
mode a
4 digit code number set by pilot
mode c
a/c alt
radar services available to VFR flights
- navgation assistance
- traffic info
- weather info
limatations of gnss
GPS errors and human errors
precuations when inserting GNSS data
- mode error (make sure correct mode is selected)
- data etry error (small keypad makes it common for the wonrg button to be pushed)
precautions when using GNSS and maintaining a good lookout
it shoudl only be used as a supplemnet to vfr navigation as erros may occur and it also doesnt shown other a/c in the vincinity or weather etc
precautions when using gnss in marginal weather conditions
a pilot will aim to fly as accurately as possible to a reporting point and chances are other pilots in the vicinity are doing the same so the risk of collision has increased
factors influencing gnss relaiability
- multipath error (signals arrive at reciever from different directions and different times)
- ionospheric propagation (charged particles in the ionsphere interfer with speed of satellite signals)
- tropospheric propogation (water vapour slows down satelitte signals causing ranging errors)
- reciever errors (diffuculity of reciever matching code with satelitte)
- interference ( satelitte signals are weak and interference sources can degrade accuracy of equipment)
SARTIME
When lodging a flight plan you are required to nominate a SARTIME which is the time that search and rescue will be alerted if a piloit has not terminated a flight plan. IF your flight is delayed and SARTIME will be exceeded then amend SARTIME by radio
