Traffic Collision Avoidance System (TCAS) Flashcards
What is the purpose of TCAS?
To prevent mid air collisions
Does the TCAS need ground stations to function?
TCAS is independent from the ground
What is TCAS based on?
SSR transponder signals and mode S
What does TCAS 1 give us?
- monitors traffic 40miles around the plane
- bearing and altitude
- can give a Traffic Advisory warning
Can TCAS 1 give Resolution Advisories?
TCAS 1 cannot give resolution advisories it is all up to the pilot
Which version of TCAS is mostly used in commercial aviation?
TCAS 2
What improvement does TCAS 2 have from TCAS 1?
TCAS 2 can give Resolution Advisories
What is Preventative RA?
To tell pilots not to deviate from their current vertical speed
What does CPA stand for?
Closest Point of Approach
Is TCAS based on time?
Yes
What improvement does TCAS 3 have over TCAS 2?
Gives TA/RA with horizontal and vertical maneuvers (turn right climb/turn left descend)
Which TCAS version uses mode S for additional info in the transponder reply?
TCAS 4
How does TCAS 4 help generate a horizontal resolution to the RA?
TCAS 4 encodes its own position
What are the possible on board equipment of TCAS?
- Dedicated instrument
- VSI
- PFD/MFD
- EHSI
What happens in Standby mode?
- TCAS does not interrogate
- transponder only responds to discrete
- used on ground, outside of runway
Which mode does the transponder reply to all ground and TCAS interrogations but the TCAS is still on stand by?
Transponder mode
What happens in Traffic Advisory mode?
- Issues proper interrogations and performs all tracking functions
- Only TA, no RA
Which mode is TA and RA active and is mandatory for commercial aviation?
Automatic
The aircraft interrogates at which frequency?
1030MHz
Is a mode C or S needed for TCAS?
Yes
How do you get distance?
The time it took from interrogation and response
How do you get altitude?
Reported by the interrogated aircraft (mode C or S)
How do you get the bearing?
Using the directional antenna
How many targets can the TCAS keep track of?
30 targets
If the symbol is a white/cyan diamond thats not coloured in, what is it?
Non-threat
What symbol and colour is a proximate traffic?
Coloured in white/cyan diamond
What does a yellow/amber circle signify?
Intruder, TA, 40s away
What symbol is shown if an aircraft is 25s away and an RA is given?
Red square
How does TCAS auto negotiate a mutual avoidance maneuver?
Using mode S transponder
Which has priority, TCAS RA or ATC?
TCAS RA
Are both mode S antennas directional or omnidirectional?
Directional
Is the bottom TCAS antenna only directional?
No it can be omnidirectional
What is the purpose of the Whisper Shout Technique?
To reduce synchronous garble
How does the Whisper Shout Technique work?
- Talk to nearby airc. first then sending a specific P2 pulse in the next Tx so they don’t reply
- Low power first, then at 24/s max power of 250W
What is our sensitivity level at 5000-10000ft?
SL at 5
What is the TAU TA and RA?
TA=40s
RA=25s
What is DMOD and what are the TA and RA?
DMOD is the slow encroachment of an aircraft behind or beside you
TA at 0.75NM
RA at 0.55NM
What is the Altitiude threshold above and below the aircraft?
TA is 850ft above and below
RA is 600ft above and below
During mode S surveillance, the extended squitter interrogation happens every how many seconds?
Every 5s and increases once per second the closer it is
Does mode S surveillance need directional antenna to get bearing and distance?
No it does not need the directional antenna to get bearing and distance
