5G and Aviation Safety
The FAA is working on measures to ensure that radio signals from newly activated wireless telecommunications systems can coexist safely with flight operations in the United States, with input from the aviation sector and telecommunications industry.
Check here for information and updates as this work continues.
The Safety Issue
Safety is our mission, and it guides all of our decisions. In the United States, 5G services are planned for launch beginning January 19 using frequencies in a radio spectrum called the C-band. These frequencies can be close to those used by radar altimeters, an important piece of safety equipment in aircraft. To make sure that this does not lead to hazardous interference, the FAA requires that radar altimeters are accurate and reliable.
Disruption Risk to Aviation from 5G
Because the proposed 5G deployment involves a new combination of power levels, frequencies, proximity to flight operations, and other factors, the FAA will need to impose restrictions on flight operations using certain types of radar altimeter equipment close to antennas in 5G networks.
These safety restrictions could affect flight schedules and operations, affecting the aviation system. Before and after the 5G deployment begins, the FAA will continue to work every day to reduce effects of this disruption as we make progress to safely integrate 5G and aviation.
Collaborative Work Underway to Reduce Delay, Cancellation Risk
Approved radio altimeters will allow commercial aircraft to continue low-visibility landings in the 5G C-Band deployment areas.
The agency has made progress during the last two weeks to safely reduce the risk of delays and cancellations as altimeter manufacturers evaluate data from the wireless companies to determine how robust each model is. This work has shown some altimeters are reliable and accurate in the 5G areas; others must be retrofitted or replaced.
Progress during the two-week deployment delay
Delaying 5G deployment for two weeks allowed the FAA, the aviation community and wireless companies to reduce the risk of delays and cancellations.
During that time, the FAA has:
- Received vital 5G transmitter location and power level information from the wireless companies
- Facilitated data sharing between avionics manufacturers and wireless companies
- Worked with airlines to help manage and minimize potential delays and cancellations in affected areas.
- Determined that some GPS-guided approaches may be used at certain airports
- Educated aviation stakeholders about what they can expect when 5G C-band is deployed on Jan. 19
- Worked with airlines on how they can demonstrate altimeters are safe and reliable in the 5G C-band environment. This is known as the Alternative Method of Compliance (AMOC) process.
Airports with 5G buffers
Telecommunications carriers have offered to voluntarily delay 5G deployment by two weeks and to restrict their own antenna operations in areas close to key airports where interference could lead to significant disruptions. The FAA, working with the aviation community and wireless companies, established buffer zones around 50 airports with wireless transmitters in close proximity to the runways.
Questions and Answers
I’ve heard about 5G already being deployed in other countries, such as France and Japan, with no issues. Why would the U.S. be different?
The U.S. airspace is the most complex in the world, and the FAA holds ourselves and our aviation sector to the highest safety standards. Deployments of 5G technology in other countries often involve different conditions than those proposed for the U.S., including:
- Lower power levels
- Antennas tilted downward to reduce potential interference to flights
- Different placement of antennas relative to airfields
- Frequencies with a different proximity to frequencies used by aviation equipment
- The early stages of the 5G deployment in the U.S. will include mitigations that are partly similar to those used to help protect air travel in France. However, even these proposals have some significant differences.
- Planned buffer zones for U.S. airports only protect the last 20 seconds of flight, compared to a greater range in the French environment.
- 5G power levels are lower in France. In the U.S., even the planned temporary nationwide lower power levels will be 2.5x higher than in France.
- In France, the government required that antenna must be tilted downward to limit harmful interference. Similar restrictions do not apply to the U.S. deployment.
NOTAMs, AMOCs. The FAA uses many acronyms. Translate for me.
NOTAMs stands for Notice to Air Missions. They provide information on restrictions or procedures that pilots and others need to follow.
AMOC stands for Alternative Means of Compliance. The AMOC process allows operators or manufacturers to demonstrate alternative ways to mitigate an unsafe situation. This process will be used to clear altimeters that have been proven to be reliable and accurate in the high-powered 5G environment.
What are radio altimeters?
Radio altimeters provide highly accurate information about an aircraft’s height above the ground. Data from these radio altimeters informs other safety equipment on the plane, including navigation instruments, terrain awareness, and collision-avoidance systems.
The FAA says 5G “may” cause interference. So how do you know there’s a safety risk?
Aviation in the U.S. is the safest in the world. That’s because we rely on data to mitigate risk, and never assume that a piece of equipment or a given flight scenario is safe until this can be demonstrated. If there’s the possibility of a risk to the flying public, we are obligated to restrict the relevant flight activity until we can prove it is safe.
If any airport is not on the list, does that mean low-visibility flights cannot occur?
Not necessarily. In many areas of the country with other airports, 5G C-band is not being deployed currently. Examples of these airports are Denver International Airport, Hartsfield-Jackson Airport in Atlanta and Ronald Reagan Washington National Airport. For other airports, 5G towers are far enough away that a natural buffer exists.
What criteria did the FAA use to select the airports?
In addition to asking for input from the aviation community, the FAA selected the airports based on their traffic volume, the number of low-visibility days and geographic location factored into the selection.
Will aircraft at airports that have these buffers be able to perform low-visibility landings?
Aircraft will be required to have an altimeter that has been proven to be accurate and reliable in the U.S. 5G C-band environment.
Why are we only hearing about this now?
The FAA, the aviation industry, telecommunications companies, and their regulators, have been discussing and weighing these interference concerns for years, in the U.S. and internationally. Recent dialogue has helped to establish information sharing between aviation and telecommunications sectors and newly agreed measures to reduce the risk of disruption, but these issues are ongoing and will not be resolved overnight.
- DOT and FAA letter to AT&T and Verizon
- SAIB: AIR-21-18R1 - Special Airworthiness Information Bulletin on the Risk of Potential Adverse Effects on Radio Altimeters
- SAFO 21007 - Safety Alert for Operators on Risk of Potential Adverse Effects on Radio Altimeters when Operating in the Presence of 5G C-Band Interference
- AD 2021-23-12 - Airworthiness Directive on altimeter interference and airplanes
- AD 2021-23-13 - Airworthiness Directive on altimeter interference and helicopters
- FCC Partial Economic Areas (PEAs) 1-4, 6-10, 12-19, 21-41, and 43-50
- DOT Letter to NTIA re: FCC3.7 GHz Band Auction
FAA Statements on 5G
"We recognize the economic importance of expanding 5G, and we appreciate the wireless companies working with us to protect the flying public and the country’s supply chain. The complex U.S. airspace leads the world in safety because of our high standards for aviation, and we will maintain this commitment as wireless companies deploy 5G." — U.S. Transportation Secretary Pete Buttigieg
January 17, 2022
With safety as its core mission, the FAA will continue to ensure that the traveling public is safe as wireless companies deploy 5G. The FAA continues to work with the aviation industry and wireless companies to try to limit 5G-related flight delays and cancellations.
Today, the FAA cleared an estimated 45 percent of the U.S. commercial fleet to perform low-visibility landings at many of the airports where 5G C-band will be deployed on Jan. 19.
The agency approved two radio altimeter models that are installed in a wide variety of Boeing and Airbus planes. This combination of aircraft and altimeter approval opens up runways at as many as 48 of the 88 airports most directly affected by 5G C-band interference.
As of Jan. 5, none of the 88 airports would have been available for landing during low-visibility conditions. The wireless companies agreed to create buffer zones for six months around airports where transmitters are in close proximity. They also agreed to delay deployment until Jan. 19 while the FAA reviewed new data detailing the location and power of wireless transmitters in all 46 U.S. markets where this service will be deployed.
Even with these new approvals, flights at some airports may still be affected. The FAA also continues to work with manufacturers to understand how radar altimeter data is used in other flight control systems. Passengers should check with their airlines if weather is forecast at a destination where 5G interference is possible.
The airplane models approved include some Boeing 737, 747, 757, 767, MD-10/-11 and Airbus A310, A319, A320, A321, A330 and A350 models. FAA expects to issue more approvals in the coming days.
The Federal Aviation Administration will require operators of Boeing 787s to take additional precautions when landing on wet or snowy runways at airports where 5G C-band service is deployed.
During the two-week delay in deploying new 5G service, safety experts determined that 5G interference with the aircraft’s radio altimeter could prevent engine and braking systems from transitioning to landing mode, which could prevent an aircraft from stopping on the runway.
The Airworthiness Notification requires crews to be aware of this risk and to adopt specific safety procedures when landing on these runways.
The directive affects 137 aircraft in the United States and 1,010 worldwide.
The FAA is working to determine which radar altimeters will be reliable and accurate with 5G C-Band deployed in the United States. Since the agreement with the wireless companies was reached, the agency has made progress to safely reduce the risk of delays and cancellations as wireless companies share more data and manufacturer altimeter testing results arrive. The FAA expects to provide updates soon about the estimated percentage of commercial aircraft equipped with altimeters that can operate reliably and accurately in the 5G C-Band environment. Aircraft with untested altimeters or that need retrofitting or replacement will be unable to perform low-visibility landings where 5G is deployed, as outlined in Notices to Air Missions (NOTAMs) published at 0000 EST Thursday, January 13, 2022.
January 7, 2022
The Federal Aviation Administration released the list of 50 airports that will have buffer zones when wireless companies turn on new 5G C-band service on January 19. The agency sought input from the aviation community where the proposed buffer zones would help reduce the risk of disruption. Traffic volume, the number of low-visibility days and geographic location factored into the selection.
Many airports are not currently affected by the new 5G deployment, even though they are not on this list. These include airports not in the 46 markets where the new service will be deployed and airports that do not currently have the ability to allow low-visibility landings.
The wireless companies agreed to turn off transmitters and make other adjustments near these airports for six months to minimize potential 5G interference with sensitive aircraft instruments used in low-visibility landings.
The FAA continues to work with the aerospace manufacturers and wireless companies to make sure 5G is safely deployed and to limit the risk of flight disruptions at all airports.
Monday, January 3, 2022
Safety is the core of our mission and this guides all of our decisions. The FAA thanks AT&T and Verizon for agreeing to a voluntary delay and for their proposed mitigations. We look forward to using the additional time and space to reduce flight disruptions associated with this 5G deployment.
- The wireless companies have offered to implement a set of mitigations comparable to measures used in some European operating environments. While U.S. standards and operating environments are unique, we believe this could substantially reduce the disruptions to air operations.
- These additional mitigations will be in place for six months around 50 airports identified as those with the greatest impact to the U.S. aviation sector.
January 2, 2022
We are reviewing the latest letter from the wireless companies on how to mitigate interference from 5G C-band transmissions. U.S. aviation safety standards will guide our next actions.
Background on Timeline
5G and aviation have safely coexisted in other countries because power levels have been reduced around airports and the industries have worked together prior to deployment. For years, we have been working to find a solution in the United States:
- Since 2015, the FAA and the world aviation industry jointly raised concerns both industries would need to address to achieve similar results and had ongoing technical discussions. In the World Radio Conference proposal, the proposal only supported an international mobile telecommunications (IMT—i.e., 5G) allocation in the 3.4 to 3.7 GHz spectrum—not the 3.7 to 3.98 GHz spectrum that is the issue for radio altimeters.
- In 2018, Boeing raised concerns and proposed a solution. Additionally, ICAO, the aviation arm of the United Nations, identified that any use of the bands near 4.2 to 4.4 GHz should be contingent upon Radio Altimeter Studies.
- In 2018, the Air Line Pilots Association raised concerns to the FCC.
- In 2020 ahead of the auction for 5G C-Band, the FAA again raised concerns and asked for a postponement to collaborate on a solution. The NTIA, the federal government coordinator on spectrum disputes, failed to put the 2020 letter into the FCC's docket.
- Throughout 2021, the aviation industry continued to ask for additional collaboration and time in anticipation of the complications we now face. The industry also held several meetings throughout the year to find solutions, including in June and October.
December 23, 2021
The FAA is working with the aviation and wireless industries to find a solution that allows 5G C-band and aviation to safely coexist. While that work is underway, the FAA alerted operators that Notices to Air Missions (NOTAMs) may be issued to restrict operations in areas where 5G interference is possible. It also provides additional information about aircraft systems that could be affected.
December 7, 2021
The FAA believes the expansion of 5G and aviation will safely co-exist. Today, we took an important step toward that goal by issuing two airworthiness directives to provide a framework and to gather more information to avoid potential effects on aviation safety equipment. The FAA is working closely with the Federal Communications Commission and wireless companies, and has made progress toward safely implementing the 5G expansion. We are confident with ongoing collaboration we will reach this shared goal.