IFF and TCAS Flashcards
What is a challenge?
Transmitted interrogation that initiates and automatic response.
What is a reply?
An automatic response to a challenge, providing altitude and four types of pre-assigned operation selected IFF codes
What provides altitude information for the IFF system?
Encoding altimeter
What frequency does IFF operate in and what is it known as?
IFF operates on the L-Band, 1000-2000 MHz. Airborne transponders receive interrogations on 1030MHz and transmit replies on 1090 MHz.
Challenging stations are opposite.
What is mode 1 of IFF?
Military only, 2 digit code.
0-7 followed by 0-3.
32 possible codes.
What is mode 2 of IFF?
Military only
4 digit codes, all 0-7
4069 possible codes
What is mode 3/A of IFF?
Military and Civilian
4 digit code with 0-7 for each digit.
4096 possible codes
What is mode C of IFF?
Military and civilian
Provides pressure altitude
What is mode S of IFF?
Military and civilian
Enhanced mode of 3/A and C.
Can contain tail number, status, altitude, heading, indicated speed, vertical rate, and in flight ID.
What is mode 4 of IFF?
Military only as encrypted mode
Classified, only transponders with correct code can communicate
What is mode 5 of IFF?
Military only as encrypted mode
Lethal?
What is ident?
On mode 1, 2, 3/A, distinguishes between two aircraft with the same code. Last 15-30seconds
What is 7700?
1277?
7700- Emergency distress code
1277- rescue
What is contained on the mission control center?
Indent, emergency, mode4/5 zeroize, IFF monitor indicator.
What does the IFF system transponder do?
Receive interrogation signal, transmits reply signal, mount for crypto appliqué
What is the crypto appliqué?
Mode 4/5 computer.
KIV-77 (mode 4 and 5)
KIV-119 (mode 4)
What is the purpose of TCAS?
Detects presence of nearby intruder aircraft equipped with transponders.
When are traffic advisories issued?
20-48 seconds prior to CPA
What is TCAS I used for?
Approximate bearing and relative altitude, typically out to 40 mm.
10-30 pax, and helos
What is TCAS II used for?
Optimum flight path strategy and resolution advisory.
Aural and visual warnings
What is the mode S transponder responsible for?
Automatically transmit 1090MHz squitter message ever second. Reply to mode S from air to air, and mode A, C and S from ground on 1090.
Tx 1030 MHz RA to air to air
Receives 26 VAC synchro reference and 28 VDC primary input pose
What is the TCAS processor?
Master control unit of the TCAS system. L-based receiver transmitter
What are the 2 types of TCAS antennas?
Directional; 4 element (0, 90, 180, 270)
Omnidirectional; l-band, blade type
Why is the purpose of IFF?
Provides identification and altitude information to civil ground station equipment.
Automatic identification of friendly IFF equipped aircraft.
