Failure of Two ADRs

TASK 27-93-00-810-929-A
Failure of Two ADRs

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 34-13-00-810-998-A	Altitude or Airspeed Discrepancy between CAPT PFD - F/O PFD - STDBY/ISIS
TSM TASK 34-13-00-810-998-B	Altitude or Airspeed Disagree between the CAPT PFD or F/O PFD and Standby Horizon Indicator or ISIS (Aircraft with RVSM capability on the three ADIRUs)
AMM 34-13-00-740-002	INTERFACE TEST of the ADR

3. Fault Isolation
Subtask 27-93-00-810-172-B

A. If the maintenance message ELAC1(2) ADR DATA DISAGREE is shown:

Refer to the POST FLIGHT REPORT and start the trouble shooting from the first NAV ADR FAULT warning and its related maintenance message.
After this step, on the upper ECAM DU the NAV ADR DISAGREE will go out of view and be replaced by NAV ADR FAULT warning with a related message.

(1) Do the Interface test of the ADR AMM 34-13-00-740-002:

Do the trouble shooting procedure related to this maintenance message.
If you do not find any maintenance message and if an airspeed discrepancy is reported by the pilot, do the trouble shooting procedure (Ref. TSM TASK 34-13-00-810-998).

[Rev.8 from Aug 2018] 2026.04.04 04:28:07 UTC