A320 System Tolerances

Question 1

What are the the times when you’ll need to make a logbook entry for the brakes in regards to system tolerances?

Answer 1

1.) The temperature between 2 brakes on the same gear differs by more than 150ºC and the temperature of one of those brakes is greater than or equal to 600ºC or less than or equal to 60ºC
2.) The difference between the LH and RH brakes average temperature is higher than 200ºC
3.) A fuse plug has melted
4.) One brakes temperature exceeds 900ºC

Question 2

What’s maximum permissible difference between altitude indications on the PFD’s (ADR 1 and ADR 2) on the ground?

Answer 2

20’

Question 3

What’s maximum permissible difference between altitude indications on the PFD’s (ADR 1 and ADR 2) at 5000’, in the clean configuration, in level flight?

Answer 3

50’

Question 4

What’s maximum permissible difference between altitude indications on the PFD’s (ADR 1 and ADR 2) at 10000’, in level flight, in the clean configuration?

Answer 4

55’

Question 5

What’s maximum permissible difference between altitude indications on the PFD’s (ADR 1 and ADR 2) at 20000’, in level flight, in the clean configuration?

Answer 5

90’

Question 6

What’s maximum permissible difference between altitude indications on the PFD’s (ADR 1 and ADR 2) at 30000’, in level flight, in the clean configuration?

Answer 6

130’

Question 7

What’s maximum permissible difference between altitude indications on the PFD’s (ADR 1 and ADR 2) at 39000’, in level flight, in the clean configuration?

Answer 7

130’

Question 8

What is the maximum permissible difference between airspeed/mach indications (ADR 1 and ADR 2) on the PFD’s, on the ground?

Answer 8

6 knots or Mach 0.008

Question 9

What is the maximum permissible difference between airspeed/mach indications (ADR 1 and ADR 2) on the PFD’s, at FL050?

Answer 9

4 knots or Mach 0.005

Question 10

What is the maximum permissible difference between airspeed/mach indications (ADR 1 and ADR 2) on the PFD’s, at FL100?

Answer 10

4 knots or mach 0.005

Question 11

What is the maximum permissible difference between airspeed/mach indications (ADR 1 and ADR 2) on the PFD’s, at FL200?

Answer 11

3 knots or mach 0.007

Question 12

What is the maximum permissible difference between airspeed/mach indications (ADR 1 and ADR 2) on the PFD’s, at FL300 and up to FL390?

Answer 12

3 knots or mach 0.01

Question 13

What is the maximum permissible difference between heading indications on the ND’s?

Answer 13

+/- 4º

Question 14

Can you operate an aircraft with a persistent veering tendency while taxiing?

Answer 14

Yes, but it must be within certain limits.

Question 15

What can you do to try and fix an aircraft with a consistent veering tendency while taxiing? How would you know when it’s out of limits?

Answer 15

You can use rudder trim in order to help it taxi straight. The following are the limitations

-Trim <= 3º means you can be dispatched with no operational limitations, no logbook entry required
-3º < Trim <= 8.8º means that you can be dispatched but you are limited to a max crosswind of 10 knots during autoland operations. A logbook entry is required.
-Trim > 8.8º means you cannot be dispatched, and immediate maintenance is required. A logbook entry is required

Question 16

When using rudder trim to taxi straight due to NWS constantly veering in one direction, what must you do before takeoff?

Answer 16

Reset the rudder trim to zero!

Question 17

In cruise flight, straight and level, under normal conditions, what should the rudder trim stay between?

Answer 17

The indicated trim should stay between 1º right to 2.3º left. Anything more than this would require a write up so MX can ensure that the indicated rudder trim corresponds to a real rudder position of no more than +/- 1.5º left or right.