Rollouts of new wireless technologies and standards have not always gone well. When the GSM system debuted, it caused hearing aids to buzz and pop with static while early cell phone signals would occasionally disrupt pacemakers. Today, as carriers expand their 5G networks across the country, they are faced with an equally dangerous prospect: that one of 5G’s spectrum bands may interfere with the radio altimeters aboard commercial aircraft below 2,500 feet, potentially causing their automated landing controls to misjudge the distance from the ground and crash.

Sticking the landing is generally considered one of the more important parts of a flight — which is, in part, why you never hear people applaud during takeoff. As such, the FAA, which regulates American air travel, and the FCC, which controls the use of our telecommunications spectrum, have found themselves at loggerheads over how, when and where 5G might be safely deployed.

5G is shorthand for 5th generation, referring to the latest standard for cellular service. First deployed in 2019, 5G operates on the same basis as its 4G predecessor — accessing the internet and telephone network via radio waves beamed at local cell antennas — but does so at broadband speeds up to 10Gb/s. However, because 5G can operate on the C band spectrum, there’s a chance that it can interfere with radio altimeters if within close proximity to airports, especially the older models lacking sufficient RF shielding.

“The fundamental emissions may lead to blocking interference in the radar altimeter receiver,” a 2020 study by aeronautics technical group RTCA, observed. “The spurious emissions, on the other hand, fall within the normal receive bandwidth of the radar altimeter, and may produce undesirable effects such as desensitization due to reduced signal-to-interference-plus-noise ratio (SINR), or false altitude determination due to the erroneous detection of the interference signal as a radar return.”

So when the FCC sold a range of C band in the 3.7 GHz to 3.98 GHz frequency range last February for a cool $81 billion, the airline industry under the umbrella of Airlines for America (which represents American Airlines, Delta, FedEx and UPS) took umbrage. These concerns prompted the FAA to issue a warning about the issue last November and led Verizon/AT&T to push back their plans to launch 5G service on C Band by a month.

This warning, in turn, prompted the CTIA (the wireless industry’s main lobbying arm) to file its counterargument shortly thereafter, asserting that aircraft already safely fly into and out of more than 40 countries that have broadly deployed 5G networks, such as Denmark and Japan. “If interference were possible, we would have seen it long before now,” CTIA President, Meredith Attwell Baker, insisted in a November Morning Consult op-ed.

However, those countries have also taken steps necessary to mitigate much of the potential issues, such as lowering the power of 5G cell towers, moving towers or simply pointing their receivers away from landing approaches.

FAA

What’s more, a causal relationship between the 5G rollout and misbehaving altimeters has yet to be established.

"The C-band is closer to the frequencies used by airplane altimeters than previous 5G deployments," Avi Greengart, lead analyst at Techsponentia, told Tom’s Guide. "In the US, the 5G we’ve been using has either been used before for prior wireless networks, or it is on really high frequencies with no ability to penetrate a piece of paper, let alone an airplane."

"There is a 200MHz buffer zone between C-band and altimeter frequencies, and the part of C-band that is opening up this week is even farther from that point,” he continued. “Additionally, similar frequencies are already in use in Europe with no problems observed. If the airplane’s altimeter filters are working properly, there should be no interference whatsoever."

Despite the CTIA’s efforts, the FAA (along with Transportation Secretary Pete Buttigieg) in late December requested Verizon and AT&T delay their primary rollout by two weeks, starting on January 5th and extending to January 17th, to give the government time to further investigate the issue. Unsurprisingly, those complex issues were not resolved within the given time frame, causing the airline industry to look towards the supposedly falling heavens and Chicken Little even harder.

In a letter obtained by Reuters, Airlines for America argued the skies would be beset by utter “chaos” amid “catastrophic” failures if 5G were deployed, potentially stranding thousands of passengers overseas. "Unless our major hubs are cleared to fly, the vast majority of the traveling and shipping public will essentially be grounded. This means that on a day like yesterday, more than 1,100 flights and 100,000 passengers would be subjected to cancellations, diversions or delays."

"We are writing with urgency to request that 5G be implemented everywhere in the country except within the approximate two miles of airport runways as defined by the FAA on January 19, 2022," the airline CEOs leaders argued. "To be blunt, the nation's commerce will grind to a halt." The airlines also objected to potential incurred costs related to better shielding their avionics (which helped alleviate the previous issues with hearing aids).

For its part, United Airlines told Reuters that it faces "significant restrictions on 787s, 777s, 737s and regional aircraft in major cities like Houston, Newark, Los Angeles, San Francisco and Chicago." That’s about 4 percent of the carrier’s daily traffic. These restrictions would apply to cargo aircraft as well as passenger planes, which will likely further exacerbate the nation’s current supply chain woes.

The FAA has conceded that 5G cellular technology could potentially cause issues but stopped short of the airline industry’s apocalyptic predictions. “Aircraft with untested altimeters or that need retrofitting or replacement will be unable to perform low-visibility landings where 5G is deployed,” the agency said in a statement, directing airlines that operate Boeing 787s, for example, to take extra precautions when landing on wet or snowy runways as 5G interference could prevent the massive airfcraft’s thrust reversers to fail, leaving it to stop using brake power alone.

AT&T is none too happy with the FAA’s course of action either. "We are frustrated by the FAA's inability to do what nearly 40 countries have done, which is to safely deploy 5G technology without disrupting aviation services, and we urge it to do so in a timely manner," an AT&T spokesperson said in a statement.

The FAA is already considering the airlines’ request for buffer zones and, on January 8th, released a list of 50 airports across the country where it plans to implement them. The agency also notes that it has cleared five models of radio altimeter to operate within low-visibility areas where 5G systems operate. These models are installed in more than 60 percent of aircraft flying in the US including the Boeing 737 - 777, Airbus’ A310 - A380, and the MD-10/-11.

"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," Transportation Secretary Pete Buttigieg, said in a statement on Tuesday.

This leaves the FAA in a tight spot. With the two week delay having already expired, Verizon is moving ahead with its 1,700-city, 100 million-customer rollout. AT&T is doing so as well, though on a more limited basis in select parts of eight metro areas including Detroit, Chicago, Austin, Dallas-Fort Worth and Houston. The agency has pledged to continue to investigate the issue and regulate based on its findings though it has not yet disclosed what steps it plans to take next for doing so.

Boeing's continued Starliner delays have prompted NASA to hedge its bets. SpaceNewsreports NASA plans to order as many as three more crewed SpaceX flights to ensure "uninterrupted" US trips to the International Space Station as soon as 2023. The company's Crew Dragon is the only system that meets partner country and safety requirements in the necessary time window, the agency said. In other words, NASA doesn't want to be without a ride to the ISS if Boeing isn't ready.

NASA was happy Boeing was focusing on "safety over schedule" for Starliner after it delayed a second orbital test to investigate an oxidizer isolation valve problem. However, that still left the administration in a bind. It was "critical" to obtain additional flights now to maintain a US foothold on the ISS, associate administrator Kathy Lueders said.

This doesn't put Boeing's capsule in danger. NASA still wanted two different crew systems to guarantee redundancy, and it planned to alternate between Crew Dragon and Starliner once both were available. Officials also stressed that the deal didn't prevent NASA from changing the contract to obtain additional flights.

Even so, the intended purchase is a blow for Boeing. Starliner plays a key role in Boeing's commercial spaceflight program and, unofficially, serves as proof the transportation veteran can compete with a fast-moving 'newcomer' like SpaceX in the private space race. The Crew Dragon backup plans reflect some lost confidence in Boeing, even if the move is only temporary.

Just two months after its maiden flight, Rolls-Royce's "Spirit of Innovation" has hit a top speed of 387.4 MPH, tentatively smashing the speed record for electric airplanes, Gizmodo has reported. It also claimed the top speed of 345.4 MPH over a 3 kilometer (1.86 mile) course and lowest time to a 3,000 meter (9,843 feet) altitude of 202 seconds. The records have yet to be certified, but if the 345.5 MPH speed stands, it would beat the current record of 213 MPH — held by a Siemens-powered Extra 330LE — by 132 MPH. 

Rolls-Royce (the aviation, not the car company), conducted the tests on November 16th. To have the records certified, it's submitting the trials to the Fédération Aéronautique Internationale (FAI), the body in charge of world aviation records. If verified, the speeds would be pretty impressive considering that the plane only made its maiden flight in September — suggesting that with more time, it could go even faster.

The Spirit of Innovation is an old-school "tail-dragger" airplane (steering at the rear) with the canopy pushed way back, that looks as fast as it goes. It's powered by a 400 kW (535 HP), 750 volt motor. Rolls-Royce said it uses the "most power-dense propulsion battery pack ever assembled in aerospace," with 6,480 cells. 

As Engadget detailed in an explainer, electric airplanes aren't practical since current batteries are 50 times less energy dense than jet fuel. However, they do hold some promise for very short trips, like a 30 minute jaunt between Vancouver and Victoria in Canada. And unlike ICE engines, electric motors retain full power as an airplane climbs, making them ideal for time-to-altitude record attempts — as the Spirit of Innovation has just shown. 

Today’s commercial airliners are not exactly fuel efficient. The average 747, for example, burns through a gallon of kerosene-based fuel every second that it flies. And with 8.2 billion people expected to take to the skies annually by 2037, carbon-free alternatives to Jet A-1 will be necessary in order to offset the industry’s impact on global warming. We are nearing the age of electric airplanes.

Pioneering researchers, scientists and entrepreneurs have been working on the dream of electrified flight since the latter part of the 19th century when heavy lead-acid batteries were loaded onto early airships to power their propellers. We’ve also seen a number of, ahem, novel means of powering aircraft while in-flight throughout the years, from conductive tethers stretching back down to the ground to solar panels to microwave energy transmission but it wasn’t until the advent of relatively more power-dense Nickel-cadmium (NiCad) battery technology that human-scale free-flying electric planes became technically feasible.

But even as battery chemistries have evolved and energy densities have risen over the past few decades, today’s state of the art Lithium-ion cells pose the same quandry to the aviation industry as they do to the automotive: how to properly balance the energy-to-weight ratio of their batteries.

“If a jumbo jet were to use today’s batteries, 1.2 million pounds of batteries would be required just to generate the power of the jet engine it would be replacing,” University of Houston Energy Fellow, Emily Pickrell, opined in Forbes earlier this year. “This weight would effectively need an additional eight jet planes just to carry that weight!"

And as Li-ion technology has fully matured, further increases to its energy density have fallen to below five percent with each annual iteration, which is why a number of researchers and battery companies are already looking for the next breakthrough battery chemistry — whether that’s Sodium-ion (Na-ion), Lithium-metal (Li-metal), Lithium-Sulphur (Li-S), or Zinc-air (Zn-air).

Regardless of composition, batteries need to get a whole lot lighter and more energy dense if they’re going to attack and dethrone jet fuel which, with an energy density of 9.6 kWh/L, makes the flammable liquid about 50 times as energy dense as today’s best li-ions. To be fair though, due to inefficiencies inherent to internal combustion engines, that figure drops to around 14 times the energy density of a li-ion battery if you’re comparing equal weights of fuel and batteries.

For example, a Tesla Model 3’s li-ion-based battery boasts an energy density of 260 Wh/kg while CATL announced earlier this year that it had built a sodium-ion battery with 160 Wh/kg density (though it hopes to get that up to 200 Wh/kg by 2023). Lithium-sulfur batteries have shown the capacity to hold up to 600 Wh/kg, though that technology faces significant longevity hurdles (i.e. the chemistry tends to eat through electrodes) before they can be widely used. Currently, 2- and 4-person small aircraft outfitted with electric power systems typically operate at 250-270 Wh/kg of specific energy but industry experts expect energy densities will have to hit 350 - 400 Wh/kg before the electric aviation industry really takes off — something that could happen within the next few years, according to Tesla CEO, Elon Musk.

Preventing and mitigating thermal runaway is another critical test for electric aviation. When a battery cell, or even an area within a single cell, malfunctions due to mechanical, thermal, or electrochemical failure, its temperature can rise beyond safe levels causing the cell to first produce lithium off-gasses, causing the cell walls to bulge, then rupture, releasing the entirety of its energy reserve. When a cell bursts it can damage and overheat surrounding cells, setting off a cascading failure that results in explosion and fire. When that happens to a Chevy Volt, the car will likely be a write off (fingers crossed it didn’t also set your house on fire) but if such a failure were to occur in-flight on an electrified 747, the loss of life would be catastrophic.

To minimize the chances of a full-blown runaway from occurring, early detection of cell failures is key. As off-gassing typically occurs minutes before a cell ruptures, the presence of a monitoring system which compares sensors positioned close to a li-ion battery against those collected by a reference sensor further away can alert for the presence of a failing cell. And to negate any gases that have already been released, fire suppression systems armed with inert gas — to prevent the offgasses from reaching combustible levels when mixed with atmospheric oxygen — can be employed as well. Of course regular maintenance and robust inspections also help prevent cell failures before the situation becomes explosive.

Rolls-Royce

Battery electric planes will also provide unique challenges in balancing air speed and range, though for Rolls-Royce, it’s not even a question — speed all the way. Over the past few years, Rolls-Royce has been quietly working on Project ACCEL (accelerating electrification of flight), building a battery-powered racing plane, dubbed Spirit of Innovation, in an effort to set a new world air speed record.

The record was previously set in 2017 when an electric-powered Extra 330LE, using a Siemens eAircraft-built power plant, notched a 209.7 mph (337.5 kph) top speed over a 3-kilometer-long course. The feat was certified by the World Air Sports Federation (FAI) as the fastest electrically powered flight by an aircraft weighing less than 1,000 kg at takeoff, beating the previous record (set in 2013) by just over 8 mph (13 kph).

In addition to the 3-kilometer record, Rolls-Royce has the opportunity to also set FAI records for a 15km distance and “time to altitude,” basically how quickly the plane can take off and reach a specific height. “It needs to be a significant number,” Rolls-Royce Director of Engineering and Technology – Civil Aerospace, Simon Burr, told Aerosociety. “We’re planning to fly over 300mph. We’ll see how high we can get to.”

Rolls-Royce

For its attempt, Rolls-Royce — which is partnering with the UK’s YASA electric motor manufacturer and start-up Electroflight, which makes bespoke battery systems — has acquired a pair of Sharp Nemesis NXT twin-seat air racers. One has been used for ground testing while the second will conduct the actual flights. The Nemesis NXT already holds the 3km FAI record with a recorded top speed of 415mph (667.8km) using a 400hp Lycoming internal combustion engine.

The Rolls-Royce team has swapped that Lycoming engine out for a trio of YASA 750v electric motors producing around 400kW (530hp) while the fuel tank has been replaced with three independent battery packs.

Rolls-Royce

“The main challenge of electrification is weight,” Rolls-Royce Flight Test Engineer Andy Roberts said during a September media briefing. Not only did the 6,000-cell battery system aboard the Nemesis NXT shift the aircraft’s center of balance, the 450kg battery system also doesn't get lighter over time as conventional fuel tanks would, which could impact the plane’s performance during the later stages of the run. The batteries are so substantial that Rolls-Royce Chief Test Pilot Phill O’Dell had to lose 2kg of bodyweight to help keep the overall aircraft weight within operating margins.

Thermal runaway is a very real concern for the Rolls-Royce team, as they’ll be pushing these batteries to their absolute limits during the flight. In order to mitigate this issue cells are separated by liquid-cooling plates and stored in cork-wrapped fireproof cases (the porous cork material helps diffuse heat). Should a cell overheat to the point of venting off-gasses, the plane is equipped with an inert gas suppression and ventilation system as well.

On September 15th, the Spirit of Innovation made its maiden test flight from the UK Ministry of Defence’s Boscombe Down airfield, flying for 15 minutes. The company hopes to have the Nemesis ready for an official run at the record before the end of this year.

“The first flight of the Spirit of Innovation is a great achievement... We are focused on producing the technology breakthroughs society needs to decarbonize transport across air, land and sea, and capture the economic opportunity of the transition to net zero,” Warren East, Rolls-Royce CEO, said in a statement. “This is not only about breaking a world record; the advanced battery and propulsion technology developed for this programme has exciting applications for the Urban Air Mobility market.”

Rolls-Royce is far from the only company pursuing electric aircraft technology, no matter how much faster it is than the competition. From tiny startups to industry stalwarts — even NASA — companies and governments around the world are racing to develop commercially viable electric aircraft both for passenger flights and cargo hauling. 

Guglielmo Mangiapane / reuters

Bye Aerospace, for example, builds electrified 2-seat trainer planes called the eFlyer, similar in function to Diamond Aircraft’s eAircraft. Slovenian aircraft manufacturer Pipistrel has been selling its $140,000 Alpha Electro, the first electric plane to earn FAA certification, since 2018. On the other end of the spectrum you have aerospace giants like Airbus developing the Air Race E, which the company claims is the world’s first all-electric air race series when it starts up later this year (better get with the times, Red Bull Air Race), and demonstrators like the City Airbus, a 4-seat eVTOL. These electric vertical take off and landing capable vehicles have become a popular option for fossil fuel-free air travel, such as Cadillac’s single-seater concept, the build-it-yourself Jetson Aero, China's EHang AAV, Uber’s since-abandoned air taxi scheme or Volocopter’s ongoing air taxi scheme.

Unfortunately, despite all the research into and hype surrounding electrified air travel, many industry experts remain skeptical that we’ll see its widespread adoption for at least a few more decades — at least for large-scale airframes like the Boeing 787 or Airbus A350. Until battery technologies become sufficiently robust, we’ll most likely see eVTOLS restricted to short-hop intracity duties for the foreseeable future, eventually expanding out to inter-city jaunts and regional commuter jets. Still, it beats sitting in traffic.

Rolls-Royce, best known in aviation for its jet engines, has taken an all-electric airplane on its maiden voyage. The "Spirit of Innovation" completed a 15 minute flight, marking "the beginning of an intensive flight-testing phase in which we will be collecting valuable performance data on the aircraft’s electrical power and propulsion system," the company announced. 

Rolls Royce said the one-seat airplane has "the most power-dense battery pack every assembled for an aircraft." The aircraft uses a 6,000 cell battery pack with a three-motor powertrain that currently delivers 400kW (500-plus horsepower), and Rolls-Royce said the aircraft will eventually achieve speeds of over 300 MPH. 

The flight comes about a year after the originally scheduled takeoff and about six months after taxi trials. Rolls-Royce is also developing an air taxi with manufacturer Tecnam, with the aim of delivering an "all-electric passenger aircraft for the commuter market," according to the companies. It has previously teamed with Siemens and Airbus on another e-plane concept. 

Aircraft companies have been exploring electric airplanes for a number of years, as air travel and cargo accounts for an increasing amount of greenhouse gases. The World Wildlife Foundation has called it "currently the most carbon intensive activity an individual can make." 

Weight is a much bigger problem for airplanes that it is for cars, however. Ford's all-electric Lightning pickup weighs 1,800 pounds more than the gas-powered model, and offers a range that's slightly under half. However, if you added 1,800 pounds to to a Cessna 206 Turbo Stationair, you'd exceed its useful load by 500 pounds before you even loaded passengers (or the pilot) — so it wouldn't even get off the ground. 

The project was half funded by the Aerospace Technology Institute and UK government, with the aim of eventually creating all-electric passenger planes. "This is not only about breaking a world record; the advanced battery and propulsion technology developed for this programme has exciting applications for the Urban Air Mobility market and can help make ‘jet zero’ a reality," said Rolls-Royce CEO Warren East.  

NASA just took an important step toward making flying taxis a practical reality. The agency has started flight testing with Joby Aviation's electric VTOL aircraft to help model and simulate future airspace with these taxis in service. The dry run began quietly, on August 30th, and will last through September 10th. The effort will include noise check using 50 microphones to gauge the "acoustic profile" of the air taxi throughout the course of a given flight.

This is the first eVTOL test as part of an Advanced Air Mobility campaign meant to spot gaps in the Federal Aviation Administration's rules and ensure the agency is ready for commercial use of flying taxis alongside delivery drones and other unconventional aircraft. The data from the flight program will help with a fuller set of campaign tests in 2022 involving both other taxis and more complicated flight situations.

The overall program could better prepare the US for a glut of low-altitude air traffic if and when flying taxis enter widespread use. The early testing is also a minor coup for Joby. It's ushering in crucial testing not long after buying Uber's air taxi business and taking a $394 million investment from Toyota. There's no telling if Joby will continue to play a prominent role, but this is clearly the kind of collaboration it was hoping for.

It could be months before Boeing takes another stab at a Starliner test flight. The company is detaching the capsule from an Atlas V rocket and taking it back to the factory to fix an issue with four propulsion system valves. The problem led to Boeing scrapping the planned second test flight on August 3rd.

Boeing will conduct "deeper-level troubleshooting" of the valves at its Commercial Crew and Cargo Processing Facility at the Kennedy Space Center. Engineers attempted to fix the problem while the Starliner was still on top of the rocket — they managed to repair the nine other valves. Boeing, NASA and Atlas V maker United Launch Alliance will need to find a new launch date when Starliner is ready.

However, as SpaceNews notes, the next opportunity for a test flight could be months away. Boeing may have to wait until after the October launches of NASA’s Lucy asteroid mission and SpaceX’s Crew-3 mission, as well as the return of the Crew-2 spacecraft. So, even if Boeing can fix the valves quickly, it could be November before Starliner can get back on the docking port.

The next time you're on a plane, searching for a Wi-Fi connection while soaring thousands of feet above the ground, don't look for the Gogo name. The longstanding standard of in-flight internet, Gogo Commercial Aviation, has been rebranded to Intelsat.

Intelsat, an international satellite communications provider, purchased Gogo Commercial Aviation in December 2020. It was a cash deal valued at $400 million. Gogo still exists and focuses on business aviation services.

Gogo has been a staple of in-flight entertainment for the past decade, partnering with 17 major airlines. The service is as impressive as it is frustrating, though it's improved with time. In 2019, Gogo announced plans to roll out 5G in-flight services this year, and it began testing those antennas in June. As Intelsat, 5G is still the goal.

“This name change is happening while Intelsat is leveraging its unparalleled global orbital and spectrum rights, scale and partnerships to build the world’s first global 5G satellite-based software-defined network of networks,” Intelsat CEO Stephen Spengler said in a press release.