Altitude discrepancy between CAPT and F/O PFDs and airfield altitude more than 75 ft

TASK 34-13-00-810-A03-A
Altitude discrepancy between CAPT and F/O PFDs and airfield altitude more than 75 ft

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 34-10-00-170-002	Flushing of the Principal Static Pressure Lines
AMM 34-11-16-000-001	Removal of the Static Probe
AMM 34-11-16-400-002	Installation of the Static Probe
AMM 34-13-00-720-010	Functional Test of the ADM Accuracy
AMM 34-13-00-790-002	Leak Test of the Principal Static and Total Air Data System

3. Fault Confirmation
Subtask 34-13-00-710-158-A

A. Test

Make sure that the displayed QNH data on the CAPT and F/O PFDs is correct.
If necessary, set the correct QNH value on the two PFDs using the BARO REFERENCE SELECTOR KNOB on the FCU.
Check the altitude indications on the two PFDs.

4. Fault Isolation
Subtask 34-13-00-810-269-A

A. If the altitude discrepancy between the two PFDs and the airfield elevation is more than 75 ft :
(1) Do a visual inspection of the static probes.
(a) If one static probe is damaged, replace it AMM 34-11-16-000-001 and AMM 34-11-16-400-002.
(2) If the fault continues:

do the flushing of the principal static pressure lines AMM 34-10-00-170-002

(3) If the fault continues:

do the leak test of the main air data system AMM 34-13-00-790-002.

(4) If the fault continues:

do the functional test of the ADM accuracy AMM 34-13-00-720-010.

Subtask 34-13-00-710-159-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:32:33 UTC