The altimeter design problem goes back decades. "Fundamentally, the problem is a design issue with the aviation industry's radar altimeters," Dennis Roberson, who runs a technology consulting firm and is a research professor at Illinois Institute of Technology, told lawmakers during a House subcommittee hearing in February.

When altimeters were designed, "they had very low-power neighbors, i.e., satellites beaming their information to the earth from very distant orbits... This led the early designers of the altimeters to decide they really could ignore their assigned spectrum boundaries, and as a result they allow transmitted energy far outside their band into the receiver," Roberson explained.

The aviation industry's slowness in fixing altimeters may lead to the FCC cracking down on bad wireless receivers. In April, the FCC voted unanimously to launch an inquiry into poorly designed wireless devices that receive transmissions from outside their allotted frequencies.

The inquiry could result in new receiver regulations similar to the rules that already require wireless devices to transmit only in their licensed frequencies. "To avoid harmful interference, we typically have rules about how and when transmitters can operate," FCC Chairwoman Jessica Rosenworcel said at the April meeting. "But wireless communications systems involve transmitters and receivers... so we need to rethink our approach to spectrum policy and move beyond just transmitters and consider receivers, too."