NOTAM: Radio Altimeter Unreliable Due to 5G C-Band Interference

[c1yd3i]

!PHL 01/165 PHL AD AP RDO ALTIMETER UNREL. AUTOLAND, HUD TO TOUCHDOWN, ENHANCED FLT VISION SYSTEMS TO TOUCHDOWN, HEL OPS REQUIRING RDO ALTIMETER DATA TO INCLUDE HOVER AUTOPILOT MODES AND CAT A/B/PERFORMANCE CLASS TKOF AND LDG NOT AUTHORIZED EXC FOR ACFT USING APPROVED ALTERNATIVE METHODS OF COMPLIANCE DUE TO 5G C-BAND INTERFERENCE PLUS SEE AIRWORTHINESS DIRECTIVES 2021-23-12, 2021-23-13 2201190501-2401190501

[reindeer76]

For context, most commercial airline pilots use autoland infrequently, around 1% to 2% of landings, or less. However, during low visibility conditions (fog), autoland is sometimes mandatory to be able to land at all.

In manual landings, I could expect that radio altimeter interference can still disturb the altitude callouts and terrain warnings.

[turrican]

I’m an airline pilot that operates heavily in the Northeast US (lots of fog). It’s much less than 1% of landing where minimums below a standard ILS are necessary. I would guess I have to use a CAT II/III ILS approach maybe once a year.

These 5G NOTAMS are at most major airports now though, and they affect more than just auto land. From what I’ve seen, any approach that uses a radio altimeter is restricted at the moment. I wonder how long the FAA plans on keeping this up.