IFR.2.4 Basic Instrumentation

Question 1

IFR.2.4.1 RBI

What’s an RBI?
How many types of RBI are there?

Answer 1

• Relative Bearing Indicator
• 2 types of RBI:
  
  • RBI Fixed-Card Indicator
  • RBI Movable-Card Indicator

Question 2

IFR.2.4.1.1 RBI Fixed-Card Indicator

How many needles does it have?
What heading does it always indicate?
What does the moving needle indicate?
How is the RB read?

What’s the formula to have the Magnetic Bearing?

Answer 2

• One needle, and a fixed (not movable) compass rose.
• The compass rose always indicates heading North at the top of the instrument
• Moving needle indicates RB to the station, relative to the longitudinal axis of the aircraft (for and aft axis)
• Clockwise from 0 until the value the needle is pointing

MB = RB + Hdg

Question 3

IFR 2.4.1.1 RBI Movable-Card Indicator

What’s the advantage of this instrument?

If we want to go to a station, what do we do if we are on a certain heading and the needle is pointing in a different direction?

Answer 3

• The compass rose can be rotated manually by the pilot
• We follow the needle in order to go to the station

Question 4

IFR 2.4.2 RMI (Radio Magnetic Indicator)

What do you see at the top on this instrument? Why?

What does the needle tell us?

How are the bearings given by this instrument?

What does the needle have?

Answer 4

• Our present heading. Because it is enslaved to the magnetic compass (normally)
• It shows us the position of the navaid.
• Bearings are magnetic
• Arrowhead and a Tail

Question 5

IFR 2.4.2 RMI (Radio Magnetic Indicator)

What does the Arrow Head do? To what is this heading bounded?

Where is the Tail of the needle found? What info does is give us? What’s the common name of this heading?

Answer 5

• Position of navaid. Heading of arrow is bound to the navaid directly, and it will be the TRACK or ROUTE (QDM)
• Reciprocal heading from the navaid. The common name of this heading is the RADIAL of the navaid (QDR)

Question 6

IFR 2.4.2 RMI (Radio Magnetic Indicator)

What considerations do we need to have in IFR Maneuvers when…?

-ATC requests us to fly on RADIAL 170º inbound

-ATC requests us to fly on TRACK 330º

• What hapens if ATC requests us to fly a RADIAL 170º?

Answer 6

• It is the same as flying on TRACK 350º
• It is the same as flying on RADIAL 150º inbound
• It means that we will intercept the QDR (Tail of the Needle) 170º, or will fly on course 170º from the navaid.

Question 7

IFR 2.4.3 CDI Course Deviation Indicator

What does the CDI show?

What does the course shown at the top/centre of the dial give us?

Who decides the TO/FROM indication?

How many dots does an HSI have? How many degrees per dot?

Answer 7

• CDI shows angular difference between the Required Course and the actual VOR Radial the aircraft is on.
• The Required Course to fly to achieve the desired aim
• Decided by the instrument
• 2 Dot or 5 Dot display
  • In a 2 Dot display; 1 Dot = 2º
  • In a 5 Dot display; 1 Dot = 5º

Question 8

IFR 2.4.1 Other CDI Presentations

Answer 8

The most common HSI is explained on IFR 2.4.4

Question 9

IFR 2.4.4 HSI

1Why is this instrument the most important in radio navigation?

What happens when the indicator points to the head of the course arrow?

What if it points to the tail of the course arrow?

What does the glideslope deviation pointer indicate? What happens if the pointer is below the centre position? what if it is above?

Answer 9

1a- It displays the Compass heading, and is slaved normally to the compass heading
1b- It has a needle as the RMI, but the middle of the needle moves. This is the CDI.
1c- It also has a TO/FROM indication

2- Shows that the course selected, if properly intercepted and flown, will take the aircraft to the selected station

3- takes the aircraft directly away from the selected station

4- Relation of acft to the G/S. If pointer is below the center position, the acft is above the G/S, and the rate of descent will need to be increased. The contrary occurs if the pointer is above the center position.

Question 10

IFR 2.4.5 EHSI

What’s the EHSI?

What information does it depict?

Answer 10

• Electronic Horizontal Situation Indicator, or Navigation Display (ND)
• Displays the following info:
• Hdg flown
• Hdg or track selected
• Beraing TO or FROM a nav beacon
• Lateral Deviation FROM a selected track
• GS, distance and time to go
• Aeronautical map
• Weather information
• extras according to design