Commercial Radio, Not Micropower, Is More Frequent Hazard for Aviation
“FCC Closes Down Unlicensed Radio Operation That Threatened Air Safety at Sacramento Airport; Fourth Report of Interference Incident in Five Months.”
So reads the Federal Communications Commission’s March 20, 1998 press release applauding its own shutdown of unlicensed broadcasters who the agency claims have caused interference to air/ground communications this year in Miami and West Palm Beach, Florida; Sacramento, California; and San Juan, Puerto Rico.
With as many as 1000 unlicensed low-power broadcasters in the U.S., it seemed worthwhile to determine what their impact on flight safety really is. We filed a Freedom of Information Act (FOIA) request with the Federal Aviation Administration for any paperwork that related to cases of air traffic communications interference by radio stations, licensed or unlicensed. The FOIA request covered the period between January 1, 1990 and May 15, 1998.
The search of the FAA’s records turned up only one case of air/ground interference by an unlicensed station. Despite the FCC’s persistent and frequent warnings of the danger posed by unlicensed low-power stations, most reports of interference in FAA files involved high-powered commercial stations, which interfered with aviation due to poorly maintained or improper equipment, illegally increased power, or simply because the FCC had allowed stations to broadcast too close to air traffic communications facilities.
“Sounds Like an Exaggeration”
In a March 20, 1998 letter to the FCC, the FAA indicated that it had received a report that an unlicensed FM station was interfering with air/ground communications at Sacramento’s Executive Airport. The FCC’s press release of the same day described the source of interference as an unlicensed station two miles from the airport.
The FAA could not locate any of the paperwork that normally accompanies an interference complaint, including who had reported the interference, the degree of interference, or the dates and times of interference. The FCC’s press release indicated that as soon as the station operators were found and informed that they were causing interference, the station immediately and voluntarily ceased operation.
So what of the FCC’s fanfare over the shutdown of three other unlicensed low power stations it claims were causing interference, the two in Florida and the one in Puerto Rico? “I’m at a loss to tell you why they [FAA] do not have anything in their records about these cases,” said Joe Casey, a spokesperson for the FCC’s Compliance and Information Bureau, in Washington.
When told of the FCC’s description of “severe interference” at San Juan’s airport, William Shumann of the FAA’s Air Traffic Division described the lack of FAA paperwork as “unusual.” Another odd feature of the San Juan case was the FCC’s use of the FBI to bust the station, a job that normally falls to the U.S. Marshals. In a phone interview from Washington, Casey explained the FBI’s involvement as one of timing: “It was an emergency situation,” he said. The idea that a microwatt FM station could cause an emergency situation at an international airport puzzled the FAA’s Shumann. “It sounds like an exaggeration to me,” he said.
“Good Engineering Ignored”
Besides the Sacramento case, all the instances of aviation interference in the FAA’s records since 1990 have involved licensed stations. In a 1996 case, the FAA found that antennas at its air station at Stukel Mountain, Oregon, were suffering interference from a set of antenna towers 1,700 feet to the south, which served four licensed TV and four licensed FM radio stations. “Once at the site, it became obvious that many site management details and good engineering practices had been ignored here,” an FAA engineering study reported. The two highest-powered FM stations at the site, which were determined to be causing the interference, were operating at 63,000 watts and 20,000 watts–hundreds of times more powerful than the largest micropower station.
These commercial stations did not seem to display the same cooperative attitude shown by the unlicensed Sacramento broadcasters. “After one and a half hours of some somewhat heated discussion, it was agreed by the [station owners] that they would pursue correcting the problems identified in my trip to the site,” the FAA engineer reported. “There was a great reluctance to commit to begin to repairs; however, this work was promised to be completed by September”–four months after this report was filed.
The FAA records reported other instances of commercial radio interference:
- A 1995 FAA survey of its Sandia Crest communications site in New Mexico indicated that there had been ongoing interference problems there since 1967, when the first licensed commercial station moved into the area.
- A 1991 FAA memo gave permission for a frequency change at the North Perry Airport in Florida. The report mentions the in-air fatal collision of a Cessna and Piper in 1990, indicating that one of the pilots may have been in a “receiver black-out area” due to a large licensed commercial radio antenna farm two miles southeast of the airport. A 1995 report on North Perry indicates that FM interference was still an issue at the airport, as it had been since at least 1976.
- A licensed FM station in Fayetteville, Ark., KKIX 103.9, caused interference for several months in 1993 and ’94 when it increased its power without warning or permission.
The FCC will no doubt continue to try to equate “unlicensed” with “unsafe.” The FAA records, however, suggest that the key to safety involves properly maintained, carefully positioned equipment–regardless of licensee status.
Tracy Jake Siska and Dharma Bilotta-Dailey are journalists based in Chicago.