Instrument Aids

Question 1

What are the frequencies used for ELTs? (Emergency Locator Transmitters)

Answer 1

121. 5 MHz and 243.0 MHz (aviation-related)

406. 025 is the COSPAS-SARSAT frequency

Question 2

What are the three types of Emergency Locator Transmitters?

Answer 2

ELT - Emergency Local Transmitter - Air
EPIRB - Emergency Position Indicating Radio Beacon - Sea
PLB - Personal Locator Beacon - Land

Question 3

What are some example alerts a GPWS system could give?

Answer 3

Excessive descent rate

Excessive terrain closure rate

Excessive altitude loss after take off or go-around

Unsafe terrain clearance while gear not locked down

Unsafe terrain clearance while landing flap not selected

Terrain rising faster than aircraft after take off

Excessive descent below ILS glideslope

Advisory Callout of Radio Height

Advisory Callout of Bank Angle

Windshear

Question 4

What systems does the GPWS require input from to function?

Answer 4

Radio altimeter

Barometric altimeter

Airspeed/Mach*

ILS glideslope receiver

Flap and Landing gear position

Angle of attack sensor*

Accelerometer inputs from Inertial Reference System*

Question 5

What is the name of the enhanced GPWS system that includes a terrain database?

Answer 5

Enhanced Ground Proximity Warning System

Terrain Awareness Warning System

Question 6

What is TCAS?

Answer 6

TCAS calculates a time to reach the CPA (Closest Point of
Approach) with the intruder, by dividing the range by the closure rate. This time value is the main parameter for issuing alerts.

Question 7

What is TCAS TA, and what should the ATC response to it be?

Answer 7

TCAS Traffic Advisory

Continue providing separation and traffic information.

Question 8

What is TCAS RA, and what should the ATC response to it be?

Answer 8

TCAS Resolution Advisory

Do not issue directions that conflict with an RA.

Question 9

What does the inertial navigation instrument in the SCNS use to obtain location information

Answer 9

INS - Inertial Navigation System (conventional gyro)
IRS - Inertial Reference System (laser gyro)

It uses a gyroscope to determine the distance and speed from an original position fix.

Question 10

What are the components of an ILS?

Answer 10

• Glide Path (Vertical Guidance)

- Localiser (Lateral Guidance)

Question 11

What are the components of an ILS?

Answer 11

• Glide Path (Vertical Guidance)
• Localiser (Lateral Guidance)
• Approach Lighting Systems

Question 12

What is the range of primary radar?

Answer 12

50 - 75nm

Question 13

What is the range of secondary surveillance radar?

Answer 13

200nm

Question 14

What is the range of secondary surveillance radar?

Answer 14

250nm

Question 15

What are the rotation rates of primary and secondary radar systems?

Answer 15

Primary - 25 / 60rpm

Secondary - 15rpm

Question 16

What problem can occur when an aircraft flies directly over a radar installation?

Answer 16

The cone of silence effect

Primary radar has a smaller cone of silence

Question 17

What is the purpose of secondary surveillance radar, and why do we still use primary radar?

Answer 17

SSR only works on aircraft with a transponder, while primary radar will provide paints of anything that enters the control zone.

Question 18

Which SSR mode gives pressure altitude?

Answer 18

• Mode C
• Mode S
• Military modes aren’t relevant

Question 19

How is navaid information transmitted to ASA?

Answer 19

• Radar Sites
• Microwaves
• Fibre-optic Cable
• Radio Link (UHF)

Question 20

What information does SSR mode C provide?

Answer 20

Pressure Altitude Encoding

Question 21

What information does SSR mode S provide?

Answer 21

24-bit code, may include ADS-B for example

Question 22

What information does SSR mode A provide?

Answer 22

Squawk Code

Question 23

How is navaid information transmitted to ASA?

Answer 23

• Radar Sites
• Microwaves
• Fibre-optic Cable
• Radio Link (UHF)

Question 24

How does Wide Area Multilateration work?

Answer 24

Uses multiple SSR receivers to triangulate an aircraft’s position.

Question 25

What is Receiver Autonomous Integrity Monitoring and what is it used for?

Answer 25

RAIM is used to assess the integrity of GPS signals. It can tell a pilot how many GPS units are presently being used to triangulate a position. The minimum number for aviation is 5.

Question 26

What is the purpose and function of GBAS?

Answer 26

Ground-Based Augmentation System

GBAS provides vertical and horizontal guidance to suitably equipped aircraft for precision approach and landings.

It consists of four reference receivers which collect navigation data from GPS satellites, a processor which provides corrections for GPS errors, GBAS-specific information as well as final approach path point and a VHF data broadcast unit to transmit digital data to aircraft.

Question 27

What is a limitation of onboard weather radar?

Answer 27

Radar Shadowing

Question 28

What is Stormscope?

Answer 28

Stormscope quickly and accurately provides real-time, flight-critical information about lightning and associated weather hazards such as turbulence and wind shear. Stormscope is unique in its ability to detect electrical activity as a storm builds, so it can show pilots which areas to avoid.

Question 29

What is Stormscope?

Answer 29

Stormscope quickly and accurately provides real-time, flight-critical information about lightning and associated weather hazards such as turbulence and wind shear. Stormscope is unique in its ability to detect electrical activity as a storm builds, so it can show pilots which areas to avoid.

Question 30

What is the radar function that allows us to identify individual aircraft?

Answer 30

Special Position Indicator (SPI) or IDENT