EASA AD US-2021-23-12
NOT ELIGIBLE FOR ADOPTION - EASA POSITION ATTACHED - SUPERSEDED BY FAA AD 2023-10-02
Summary
FAA Airworthiness Directive 2021-23-12 is a final rule affecting all transport and commuter category airplanes equipped with radio altimeters. It addresses the risk of interference from 5G C-Band wireless broadband operations in the 3.7-3.98 GHz frequency band, which can impair radio altimeter performance. This interference could affect critical flight systems relying on accurate altitude data during low visibility and landing operations.
What Changed
This new airworthiness directive requires operators to revise the limitations section of their airplane or aircraft flight manuals to prohibit certain operations that depend on radio altimeter data when 5G C-Band interference is present, as indicated by Notices to Air Missions (NOTAMs). It introduces operational restrictions at affected airports to mitigate the risk of unreliable radio altimeter data caused by 5G signals.
Why It Matters
The directive is crucial for aviation professionals because radio altimeters provide precise height-above-ground information essential for safe low visibility approaches and landings. Interference from 5G C-Band signals could cause erroneous altitude readings, potentially leading to unsafe aircraft maneuvers or loss of pilot trust in instruments. Compliance ensures continued safety during critical flight phases and maintains regulatory adherence.
What To Do
Operators must update their flight manuals to include the new limitations prohibiting certain radio altimeter-dependent operations at airports identified by NOTAMs as affected by 5G C-Band interference. They should monitor NOTAMs for changes in affected locations and ensure flight crews are trained on these restrictions. Comments on the directive were accepted until January 24, 2022, and the AD became effective on December 9, 2021.
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