This article explains about alarm generated on Fan airflow direction mismatch even if the Airflow physically matches with the type of chassis

user@switch> show chassis alarms no-forwarding

2 alarms currently active

Alarm time        Class Description

2024-11-16 10:29:57 UTC Major FPC 0 Fan & PSU Airflow direction mismatch

2024-11-16 10:29:57 UTC Major FPC 0 Fan Airflow direction mismatch

user@switch> show chassis hardware detail no-forwarding

Power Supply 0  REV 01  640-107107  xxxxxxxxxxx   JPSU-550-C-AC-AFO

Power Supply 1  REV 01  640-107107  xxxxxxxxxxx    JPSU-550-C-AC-AFO

Fan Tray 0                        Fan Module, Airflow In (AFI) ----->>>> Air Inflow Direction

Fan Tray 1                        Fan Module, Airflow Out (AFO)

Possible steps to clear that "Airflow mismatch" alarm:

• Reseat the affected FAN (This in case there is a problem to identify the correct air flow)
• Please have the same Airflow FANs to make sure the alarm goes away. 
• Swap the Fan trays between slot 0 and slot 1 of the same chassis and check if the alarm follows to that slot
  • If it does, then the Fan Tray module is unable to provide the correct details to the chassis , We'll need to replace the affected Fan Tray

By replacing the Fan tray , there were no alarms & chassis hardware output shows correct type of airflow direction on the FRU

Fan Tray 0 Fan Module, Airflow Out (AFO)

Fan Tray 1 Fan Module, Airflow Out (AFO)