Airworthiness Directive · Amendment 39-22438 · Indicating/recording system
Transport and Commuter Category Airplanes
This AD applies to all transport and commuter category airplanes equipped with a radio (also known as radar) altimeter. These radio altimeters are installed on various transport and commuter category airplanes including, but not limited to, the airplanes for which the design approval holder is identified in paragraphs (c)(1) through (18) of this AD.
(1) The Boeing Company
(2) Airbus SAS
(3) Bombardier Inc.
(4) Embraer S.A. (including type certificates previously held by Yaborã Indústria Aeronáutica S.A., which are now held by Embraer S.A.)
(5) Gulfstream Aerospace Corporation
(6) Gulfstream Aerospace LP
(7) Textron Aviation Inc.
(8) Pilatus Aircraft Limited
(9) Fokker Services B.V.
(10) Saab AB, Support and Services
(11) DeHavilland Aircraft of Canada Limited
(12) Airbus Canada Limited Partnership
(13) ATR-GIE Avions de Transport Régional
(14) MHI RJ Aviation ULC
(15) BAE Systems (Operations) Limited
(16) Lockheed Martin Corporation/Lockheed Martin Aeronautics Company
(17) Viking Air Limited
(18) Dassault Aviation
The FAA is superseding Airworthiness Directive (AD) 2021-23- 12, which applied to all transport and commuter category airplanes equipped with a radio (also known as radar) altimeter. AD 2021-23-12 required revising the limitations section of the existing airplane/ aircraft flight manual (AFM) to incorporate limitations prohibiting certain operations requiring radio altimeter data when in the presence of 5G C-Band interference as identified by Notices to Air Missions (NOTAMs). Since the FAA issued AD 2021-23-12, the FAA determined that additional limitations are needed due to the continued deployment of new 5G C-Band stations whose signals are expected to cover most of the contiguous United States at transmission frequencies between 3.7-3.98 GHz. For certain airplanes, this AD requires revising the limitations section of the existing AFM to incorporate limitations prohibiting certain operations requiring radio altimeter data, due to the presence of 5G C-Band interference. This AD also requires modifying certain airplanes to allow safe operations in the U.S. 5G C-Band radio frequency environment. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For purposes of this AD, a “radio altimeter tolerant airplane” is one for which the radio altimeter, as installed, demonstrates the tolerances specified in paragraphs (g)(1)(i) and (ii) of this AD, using a method approved by the FAA. No actions are required by this AD for radio altimeter tolerant airplanes.
(i) Tolerance to radio altimeter interference, for the fundamental emissions (3.7-3.98 GHz), at or above the power spectral density (PSD) curve threshold specified in figure 1 to paragraph (g)(1)(i) of this AD.
Figure 1 to paragraph (g)(1)(i)— Fundamental Effective Isotropic PSD at Outside Interface of Airplane Antenna
(ii) Tolerance to radio altimeter interference, for the spurious emissions (4.2-4.4 GHz), at or above the PSD curve threshold specified in figure 2 to paragraph (g)(1)(ii) of this AD.
Figure 2 to paragraph (g)(1)(ii)— Spurious Effective Isotropic PSD at Outside Interface of Airplane Antenna
(2) For purposes of this AD, a “non-radio altimeter tolerant airplane” is one for which the radio altimeter, as installed, does not demonstrate the tolerances specified in paragraphs (g)(1)(i) and (ii) of this AD.
For non-radio altimeter tolerant airplanes, before further flight, revise the Limitations Section of the existing AFM to include the information specified in figure 3 to paragraph (h) of this AD. This may be done by inserting a copy of figure 3 to paragraph (h) of this AD into the existing AFM. If an operator has complied with paragraph (g) of AD 2021-23-12, that action satisfies the requirements of this paragraph.
Figure 3 to paragraph (h)— AFM Revision
For non-radio altimeter tolerant airplanes, do the actions specified in paragraphs (i)(1) and (2) of this AD.
(1) On or before June 30, 2023, revise the Limitations Section of the existing AFM to include the information specified in figure 4 to paragraph (i) of this AD. This may be done by inserting a copy of figure 4 to paragraph (i) of this AD into the existing AFM. Incorporating the AFM revision required by this paragraph terminates the AFM revision required by paragraph (h) of this AD.
(2) Before further flight after incorporating the limitations specified in figure 4 to paragraph (i) of this AD, remove the AFM revision required by paragraph (h) of this AD.
Figure 4 to paragraph (i)— AFM Revision for Non-Radio Altimeter Tolerant Airplanes
(1) Modifying the airplane from a non-radio altimeter tolerant airplane to a radio altimeter tolerant airplane terminates the limitations in paragraph (i) of this AD for that airplane.
(2) After modifying the airplane to a radio altimeter tolerant airplane, the limitations specified by paragraph (i) of this AD may be removed from the AFM.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
