Loss of the Airspeed Data and the Mach Number on the ISIS Indicator

TASK 34-22-00-810-806-A
Loss of the Airspeed Data and the Mach Number on the ISIS Indicator

1. Possible Causes

IND-ISIS [22FN]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 34-11-15-000-001	Removal of the Pitot Probe
AMM 34-11-15-400-001	Installation of the Pitot Probe
AMM 34-22-25-000-001	Removal of the ISIS Indicator
AMM 34-22-25-170-001	Draining and Flushing of the Standby Static and Standby Total Pressure lines (ISIS)
AMM 34-22-25-400-001	Installation of the ISIS Indicator

3. Fault Confirmation
Subtask 34-22-00-700-052-A ** ON A/C NOT FOR ALL

A. Test
Not applicable, you cannot confirm this fault on the ground.

4. Fault Isolation
Subtask 34-22-00-810-057-A ** ON A/C NOT FOR ALL

A. If the fault symptom is identified by the maintenance message on the face of the ISIS indicator:
ISIS(22FN-10FC) SPEED OR MACH FUNCTION
and by the red flags on the face of the ISIS indicator:
SPD
or
M

do a visual check of the standby pitot probe.

(1) If the standby pitot probe is damaged:

replace the defective standby pitot probe AMM 34-11-15-000-001 AMM 34-11-15-400-001.

(2) If the standby pitot probe is not damaged:

drain and flush the standby total pressure line AMM 34-22-25-170-001.

(a) After the subsequent flight, if the fault continues:

replace the IND-ISIS [22FN] AMM 34-22-25-000-001 AMM 34-22-25-400-001.

[Rev.8 from Aug 2018] 2026.04.04 04:32:55 UTC