US Radar Has Detected Hundreds of Illegal Low-Flying Aircraft Attempting to Cross Border From Mexico

By Mark Browne | May 5, 2016 | 11:13pm EDT
The Tethered Aerostat Radar System is deployed at locations along the U.S.-Mexico border. (Photo: Customs and Border Protection)

Mexico City ( – Hundreds of illegal U.S.-Mexico border-crossing attempts by low-flying aircraft have been detected in the last 21 months, according to a U.S. border protection official.

U.S. radar spotted 335 “suspected cross-border attempts” by aircraft at low altitudes between July of 2014 and June of 2015, and 59 suspected attempts from July 2014 to March 31, said Carlos Diaz, a U.S. Customs and Border Protection spokesman.

A Mexico City newspaper reported this week that Mexican drug cartels have operated huge fleets of small planes and established more than 4,700 clandestine runways in Mexico to ship drugs to the border region.

Citing information released by the Mexican military, El Universal reported that 599 airplanes were seized from the Sinaloa drug cartel between 2006 and 2015—a fleet several times larger than Mexico’s largest commercial airline. Fifty-five planes were confiscated in the past three years.

The daily reported that 4,726 clandestine airstrips have been detected in Mexico since 2006.

Diaz said the border flyover attempts were spotted by a U.S. system of tethered helium balloons equipped with radar, known as TARS (Tethered Aerostat Radar System). The balloons are flown at 10,000 to 12,000 feet from eight separate stations along the border, including one in Florida and one in Puerto Rico.

Each of the TARS helium balloons covers approximately 200 miles of territory and is equipped with radar capable of “long-range detection of low-altitude aircraft at the radar’s maximum range,” according to the CBP website.

However, Diaz said the TARS system may suffer operation outages for as much as 25 percent of the time, due to bad weather.

“The TARS do not fly in adverse weather conditions so we don’t jeopardize the health of our surveillance systems, or the safety of the broad public or our flight crews,” he noted.

On the Mexican side of the border, large areas of low-altitude airspace are not monitored by the government, especially in the northern desert regions, according to security specialist Raúl Guillermo Benítez Manaut.

Low-altitude airspace over the country’s northern desert is “out of reach” of the government’s radar, he said.

“There is no 100 percent coverage. They can’t monitor the entire airspace.”

Many of the small planes used by the cartels are used for just one flight and some may cross over the border in desert regions, Manaut said, adding that some of the planes are registered to Mexican agricultural companies.

United Airlines pilot John Silcott, executive vice-president of Expert Aviation Consulting, said he’s been flying in an out of Mexico for more than 20 years and has never heard of the cartel flights.

“I would be very surprised that someone could have an operation like that and not be detected,” he said.

“Flying into Mexico City, Guadalajara, the places we go, there’s been no signs” of the cartel aviation activity, Silcott said.

He said low-flying aircraft wouldn’t pose a hazard to commercial carriers that operate at 30,000 feet and above.

He noted that unregulated small planes aren’t be allowed to approach major Mexican airports.

“If there ever were an incident where it impacted a U.S. carrier or any other airline, that would be a big problem,” Silcott said.

Ross Aimer of Aeroconsulting Experts said radar “blind spots” exist in Mexico due to topography, and in areas where there’s little or no population.

He pointed to the Mexican state of Baja California in particular. According to El Universal, some 1,025 runways were found in Baja California alone.

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