Dale Brown - Edge of Battle

CHAPTER 12

OVER SOUTHERN ARIZONA

THE NEXT EVENING

The target was more than eleven hundred miles ahead—almost six hours of one-way flying.

The aircraft made their last refueling over U.S. territory from an MC-130P Combat Shadow aerial refueling tanker low over the Sulphur Springs Valley area of south-central Arizona just before going across the border around 9 P.M. local time. Flying at less than five hundred feet aboveground, the aircraft were still spotted by U.S. Homeland Security antismuggling radar arrays and balloons, but the word had already been passed along, and no radio contact with the aircraft was ever made or even attempted.

After refueling, the two aircraft flew in close formation, with the pilots using night vision goggles to see each other at night. Each aircraft was fitted with special infrared position lights that were only visible to those wearing NVGs, so from the pilots’ point of view it was very much like flying in hazy daytime weather conditions. The pilots of each aircraft would trade positions occasionally to avoid fatigue, with the copilot of one aircraft taking over and then moving over to the other aircraft’s opposite wing. The two propeller-driven aircraft were fairly well matched in performance, with the smaller aircraft having a slight disadvantage over its four-engined leader but still able to keep up easily enough. Throughout all the position and pilot changes, and no matter the outside conditions, the aircraft never strayed farther than a wingspan’s distance from each other and never flew higher than eight hundred feet aboveground.

Mexican surveillance radar at Ciudad Juárez spotted the aircraft briefly near the town of Janos as it made its way southeast, and one attempt was made to contact it by radio, but there was no response so the radar operators ignored it. The Mexican military was tasked primarily with counterinsurgency operations and secondarily with narcotics interdiction—and even that mission ranked a very distant second—but those forces were primarily arrayed along the southern border and coastlines: in northern Mexico near the U.S. border, there was virtually no military presence at all. Certainly if a low-flying plane was spotted going south, it was no cause for alarm. A routine report was sent up the line to Mexican air defense headquarters in Mexico City, and the contact immediately forgotten.

From Janos the aircraft headed south over the northern portion of the Sierra Madre Occidental Mountains. The aircraft flew higher, now a thousand feet aboveground, but in the mountains it was effectively invisible to radar sweeps from Hermosillo, Chihuahua, and Ciudad Obregón. Over the mining town of Urique, the aircraft veered southeast, staying in the “military crest” of the mountain range to completely lose itself in the radar ground clutter. This two-hour leg was the quietest—central Mexico was almost devoid of any population centers at all, and had virtually no military presence. They received the briefest squeak from their radar warning receivers when passing within a hundred miles of Mazatlán’s approach radar, but they were well out of range and undetectable at their altitude.

The aircraft performed another low-altitude aerial refueling on this leg of the journey, ensuring that the smaller aircraft was completely topped off before continuing further. The MC-130P had a combat range of almost four thousand miles and could have made two complete round trips with ease; the smaller aircraft had only half the range and needed the extra fuel to maintain its already-slim margin of safety. Once topped off, the MC-130P orbited at one thousand feet above the ground about sixty miles northwest of the city of Durango, over the most isolated portion of the central Sierra Madre Occidental Mountain range and directly in the “dead spot” of several surveillance and air traffic control radar systems. The electronic warfare officer on board the Combat Shadow was on the lookout for any sign of detection, but the electromagnetic spectrum remained quiet as the two aircraft split up.

Just north of the city of Zacatecas the smaller aircraft jogged farther east to avoid Guadalajara’s powerful air traffic and air defense radar system. Now the aircraft was no longer over the mountains but flying in Mexico’s central valley, so it was back down to five hundred feet or less aboveground, using terrain-avoidance radar, precise satellite-guided navigation, night vision devices that made it easy to see the ground and large obstacles, and photo-quality digital terrain and obstruction charts, with computerized audio and visual warnings of nearby radio towers and transmission lines. Northeast of the city of San Luis Potosí, the aircraft made a hard turn south to avoid Tampico’s coastal surveillance radar.

Now the aircraft was flying in the heart of Mexico’s population centers, with 80 percent of the country’s population within one hundred miles of their present position—and most of the country’s air defense, surveillance, and air traffic radars as well. Plus, they had very little terrain to hide in now. Staying far away from towns and highways, relying mostly on darkness to hide their presence, the aircraft’s crew prepared for the most dangerous part of the mission. After over five hours of relative peace and quiet, the last twelve minutes was going to be very busy indeed. The crew performed their “Before Enemy Defended Area Penetration” checklist, making sure all lights were off, radios were configured to avoid any accidental transmissions, the cabin was depressurized and secure, and the crew members waiting in the cargo area were alerted to prepare for evasive maneuvers and possible hostile action.

Somehow, after the events that had transpired in the past several days, it was not hard to imagine they were flying over enemy territory—even though they were flying over Mexico.

Immediately prior to the last turning point over the town of Ciudad Hidalgo, eighty miles northwest of Mexico City, came the first radio message on “GUARD,” the international emergency frequency, in English: “Unidentified aircraft at the two-niner-zero degree radial of Mexico City VOR, seventy-three DME, this is Mexico City Center, squawk Mode Three five-seven-one-seven; ident, and contact center on one-two-eight point three two, UHF three-two-seven point zero. Acknowledge immediately.” It was repeated several times in both English and Spanish, even after the radar return completely dropped off the scope.

The message was never answered, of course—which only served to alert the Fuerza Aerea Mexicana, the Mexican Air Force, and the Interior Defense Forces of the Ministry of Internal Affairs. The Mexican Air Force had one airbase northeast of Mexico City dedicated to air defense, with nine F-5E Tiger II fighters assigned there; two were on twenty-four-hour alert. By the time the aircraft was twenty miles west of Mexico City, the fighters were airborne. But the pilots had had very little actual night low-altitude air defense training, and the radars on the American-made Tiger IIs were not designed to detect low-flying aircraft against a heavily industrialized and populated background, so the fighters could do nothing else but fly a medium-altitude patrol pattern, away from the commercial airline arrival and departure paths and surrounding high terrain, and hope that Mexican air traffic control could spot the unidentified aircraft again and vector them in close enough for visual contact.

But the Internal Affairs Ministry’s response was far different. Primarily charged with identifying, tracking, and stopping insurgents and revolutionaries that might threaten the republic, the ministry responded to every such alert, no matter how small, as if it was an impending coup or attack on the capital.