A War Begins? How Iran Shot Down a U.S. RQ-4N Surveillance Drone

Sebastien Roblin

Security,

What you are dying to know.

Early in the morning on June 20, 2019, a transporter erector launcher truck near the coastal town of Gerouk, Iran, angled its three missiles heavenward as its boxy phased array radar illuminated a target dozens of miles to the south. Gerouk overlooks one of the narrowest parts of the Straits of Hormuz through which huge oil tankers transiting to and from ports in the Persian Gulf must pass for access to the Indian Ocean.

The aircraft in question was a large U.S. Navy drone called the RQ-4N Broad Area Maritime Surveillance Drone (BAMS-D) with wings spanning 35 meters across—as wide as a 737 airliner. Converted from retired Air Force RQ-4A Global Hawk drones, the BAMS-D served as prototypes for the MQ-4C Triton maritime surveillance drones now entering service.

This RQ-4N, part of the Navy’s VX-20 Test and Evaluation squadron, reportedly took off from Al Dhafra Airbase in the United Arab Emirates at a quarter past midnight, initially remotely piloted by a specialist launch and recovery pilot. It then cruised to its station over the Persian Gulf at roughly 350 miles per hour—two-thirds the speed of a typical airliner—ascending as high as 100,000 feet high into the stratosphere.

From this lofty perch, the huge UAV soared southeast, leisurely circumnavigating the narrow Straits of Hormuz, as plotted here, it sensors scanning everything beneath it. The long-endurance drone could methodically survey up to 2.7 million square miles in twenty-four hours with its powerful multi-function radar, all the while transmitting that data back for analysis.

Periodically, the drone’s operator may have nosed it down to lower altitudes so the sensor operator could scan a ship of interest with its infrared sensor turret, or use its electromagnetic ESM sensors to triangulate the positions of nearby radar transmitters.