For years corporate radio officials have claimed the airplanes will fall from the sky because of the scourge of pirate radio. But no plane crashes have been attributed to an illegal broadcast. So when the Federal Aviation Administration and airline industry officials recently began saying airplanes could fall from the sky because of 5G signals, it sounded like another conspiracy theory. Airplane altimeters tell pilots plane altitudes, and rely on a spectrum from 4.2 GHz to 4.4 GHz. That is close to where 5G signals get sent, between 3.7 to 3.98 GHz. So, unlike FM transmissions which are not nearly as close, it is conceivable for faulty transmissions or receivers could cause problems. And, it turns out many planes have older altimeters that were designed before the age of so many cell phone signals. That led to the Federal Aviation Administration objecting to the Federal Communications Commission’s authorization of 5G networks near airports earlier this year. Now Jon Brodkin at ArsTechnica reports that the FAA has announced a plan to replace or retrofit airplane altimeters that can't filter out transmissions from outside their allotted frequencies. The FCC says interference in altimeters was unlikely to occur "under reasonable scenarios" and that the aviation industry should conduct more research "on why there may even be a potential for some interference given that well-designed equipment should not ordinarily receive any significant interference (let alone harmful interference) given these circumstances." The FAA seems to be conceding to the FCC that the problem really is not that large. "During initial negotiations in January, the wireless companies offered to keep mitigations in place until July 5, 2022, while they worked with the FAA to better understand the effects of 5G C-band signals on sensitive aviation instruments," the FAA said last week. "Based on progress achieved during a series of stakeholder roundtable meetings, the wireless companies offered Friday to continue with some level of voluntary mitigations for another year." But the airline industry is mad that they are being made responsible for the issue. "At today's FAA roundtable we were told that the vast majority of our fleet (approximately 4,800 aircraft) would need to be retrofitted by July 2023," Airlines for America, a trade group that represents the major U.S. airlines, said in a letter to the FAA. "Given that the FAA has not even approved solutions nor have manufacturers manufactured these products for most of this fleet, it is not at all clear that carriers can meet what appears to be an arbitrary deadline." Read more about this story at ArsTechnica.