HN Explorer

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

3 points by c1yd3i ↗ HN
!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

2 comments

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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.