Updated March 3, 2022

Review answers to frequently asked questions about the 5G deployment. Learn more about the history of this issue and what the impact could be for business aviation operations.

Why are industry stakeholders concerned?

The 5G networks, operating in adjacent bandwidth, could cause interference affecting the safe operation of radar altimeters and associated and integrated systems, which in turn could lead to restrictions on their use during instrument approach procedures and in low-visibility conditions.

In addition to providing direct, real-time and accurate measurements of the aircraft’s clearance over terrain or other obstacles, radar altimeters may also be integrated with other aviation equipment, including but not limited to terrain avoidance and warning systems (TAWS) and autoland capabilities, as well as equipment including ground spoilers, anti-skid braking and other seemingly unrelated aircraft systems.

The FAA has introduced new Safety Alerts for Operators (SAFOs) and ADs that would restrict operations of aircraft to a designated and potentially more limited roster of airports or airspace areas.

SAFO 21007: Risk of Potential Adverse Effects on Radio Altimeters when Operating in the Presence of 5G C-Band Interference

When did these 5G networks go live?

Verizon and AT&T initially planned to roll out their 5G networks in late 2021, but later agreed to delay that date to the first week in January 2022. After initially refusing a U.S. Department of Transportation (DOT) request for an additional, two-week implementation delay, the two providers acceded to move the planned nationwide rollout of these 5G networks to Jan. 19, 2022, which the FAA stated would provide “additional time and space to reduce flight disruptions associated with this 5G deployment.”

Both companies initiated deployment of their 5G networks on Jan. 19, 2022. However, ahead of the rollout, AT&T and Verizon further agreed to voluntarily delay 5G transmitter deployments near approximately 80 airports for an unspecified period. Per the FAA, both companies have also agreed to “a set of mitigations comparable to measures used in some European [airport and airspace] operating environments” for six months. Those mitigations are being worked through at this time.

What should I expect to happen now that these 5G networks are being deployed?

NBAA and other industry stakeholders, as well as government regulators and agencies, are continuing to gather information and share much-needed data about these developments, which affect all aviation segments, including business aviation.

As answers to key questions regarding the specific impacts to aviation from the 5G deployment are determined, NBAA will share this information so that business aircraft operators may take appropriate measures to enhance safety and to ensure the U.S. aviation system remains the world’s largest, safest and most efficient in the world.

NBAA requests that particular questions from our membership be addressed to ops@nbaa.org

What airports will be affected?

As of March 2, 2022, the FAA has issued more than 2,000 aerodrome Notices to Air Missions (NOTAMs) and instrument approach procedure (IAP) NOTAMs affecting more than 100 airports utilized by commercial and business aviation, including Part 139 certificated airports and many other non-Part 139 airports and landing facilities.

What are the potential mitigations?

Although Verizon and AT&T have agreed to keep transmission towers turned off at approximately 80 airports where those towers are within 2 miles of affected runways, those airports may still experience operational impacts from 5G signals.

Operators currently have two options:

  1. Comply with the Airworthiness Directive (AD)
  2. Utilize an available alternative means of compliance (AMOC)

If utilizing the AD, there are currently no equipment modifications available, meaning flight operations will be significantly limited at those NOTAM’d airports. However, business aviation airframe and avionics OEMs continue to work aggressively to submit AMOC applications to the FAA, many of which have already been approved, allowing operators of specific aircraft types or avionics to supersede NOTAM directives.

Operators utilizing an AMOC for their specific aircraft and equipment to continue to operate into airports that are NOTAM’d, will be required to take additional actions. The FAA reassesses these AMOCs monthly as the agency receives new information on tower deployments from the telecom companies. AMOCs also carry expiration dates and operators should continuously check with their OEM to verify they are operating under the latest AMOC. If a new AMOC is issued, per the AD, you will be required to connect with your local Flight Standards District Office (FSDO).

Keep in mind, the OEM maintains the AMOC and is the best resource for the latest information regarding that document.

The NOTAMs also call on operators to report to the agency any interference with radar altimeter operations to validate potential impact from the new 5G signals, using an online feedback capability available from the FAA.

What business aircraft may be affected?

Any aircraft equipped with a radar altimeter could have its operational capability affected by 5G interference, a matter documented by the FAA and in findings published in October 2020 by RTCA, a non-governmental organization that develops technical guidance for use by regulatory authorities and by industry. Review RTCA Paper No. 274-20/PMC-2073.

In December 2021, the FAA issued two ADs related to 5G interference – one applicable to transport category fixed-wing aircraft equipped with radar altimeters, the second to helicopters. Both ADs require operators to insert limitations into their flight manuals that would prohibit use of radar altimeter systems when operating in specific areas NOTAM’d for potential 5G interference.

FAA AD-2021-01169-T: Transport and Commuter Category Airplanes

FAA AD-2021-01170-R: Various Helicopters

Such limitations will severely curtail many aviation operations in low-visibility conditions, and may impact a variety of aircraft systems that integrate radar altimeter data, including:

  • Autoland capabilities
  • Terrain Avoidance and Warning Systems (TAWS)
  • Enhanced Ground Proximity Warning Systems (EGPWS)
  • Head Up Displays (HUD)
  • Enhanced Flight Vision Systems (EFVS)
  • Landing gear “weight on wheels” switches, tied to:
    • Aircraft pressurization
    • Thrust reversers
    • Ground spoilers/lift-dump systems
    • Anti-skid braking

Why has this seemed to come to the forefront only recently, and what is the industry doing about this?

Aviation stakeholders first raised concerns about potential 5G interference in 2015 and proposed limiting frequency allocation for such networks to a lower range of 3.2-3.7 GHz.

Ahead of the 2020 spectrum auction, NBAA joined with other aviation stakeholders in petitioning the FCC for a postponement in order to work together on a solution, and the association has joined with avionics manufacturers, aircraft manufacturers and other groups over the past year in calling on the FCC and telecommunications industry to collaborate on an effective mitigation strategy.

Aviation Groups Call for Halt of FCC Spectrum Auction Affecting Radar Altimeters

Aviation Community Petitions FCC to Revisit 5G Approvals; FAA Warns of Potential Radar Altimeter Interference

In addition to concerns about signal interference from cellular networks, NBAA has also played a significant role in efforts to mitigate concerns about GPS interference testing and outages conducted by the U.S. Department of Defense that have been demonstrated to degrade performance of certain aircraft navigational systems and flight capabilities. This includes participating in a 2017 RTCA tactical operations committee that examined such effects from the intentional jamming of GPS signals. Review NBAA’s GPS resources.

While NBAA supports advances in communications technologies that offer the potential to greatly improve data transmission speeds and voice call quality, these latest radar-altimeter interference concerns reaffirm the need for aviation stakeholders to be engaged throughout any such rollouts that could negatively affect critical aviation safety equipment.

What about other regions worldwide that have implemented 5G networks without apparent interference issues?

There is no valid comparison, in part because U.S. standards and operating environments are unique. Implementation of 5G networks in other countries and regions of the world has been technically different, with these systems operating at reduced power or utilizing different frequencies farther from the radar altimeter spectrum than the C-Band frequencies to be utilized by the Verizon and AT&T 5G networks in the U.S.

Will I still be able to fly certain instrument approaches in affected areas?

Aircraft owners should confer with their OEMs and other relevant authorities, and reference associated NOTAMs and ADs, to determine how the 5G rollout may affect their specific aircraft avionics and operational capabilities, including CAT II/III approaches dependent on radar altimeter data.

How can I get a complete and current list of the 5G related NOTAMs?

A ‘Free Text’ search of ‘5G’ on the FAA’s NOTAM Search website will pull the current list of 5G-related NOTAMs consisting of Aerodrome, Procedures and Airspace NOTAMs. As always, flight crews should pull a current standard briefing for every flight to see those NOTAMs applicable to their current operation.

With the NOTAMs now published and 5G networks going live, what happens next?

The FAA and the aviation industry will continue to assess real-world effects to aviation operations from 5G transmitters. Where possible, the agency will remove NOTAMs where restrictions can be eased, so it is critical for operators to share any 5G interference events they encounter to better inform the FAA’s data in that continual assessment. Report a 5G interference event to the FAA.

Additional NOTAMs may also be added in areas demonstrating consistent effects and interference, and as the FAA is notified by telecom providers of the deployment of additional 5G transmitters.