Radio waves reportedly can down copter
By Mark Thompson, Knight-Ridder Service
(From the Boston Globe, 8 November 1987)
WASHINGTON - The Army's most advanced helicopter to carry troops into battle can be knocked out of the sky by routine radio waves from microwave towers, radio antennas, and radars, according to Pentagon officials and documents.
Investigators believe such radio waves made five of the Army's UH-60 Black Hawks nosedive into the ground since 1982, killing 22 servicemen. The problem could be even more devastating in wartime, they said, because the Soviets are perfecting a radio-wave weapon to exploit the vulnerability…
…Radio waves in the air can enter the helicopter's wiring and electrical components and generate false commands that can range from simply flashing the warning lights to sending the craft into a fatal dive…
A three-month Knight-Ridder investigation has found:
•The Army grounded all UH-60s last year after one crashed near a high-powered citizens' band transmitter in Alabama, killing all three servicemen aboard. But Army aviation officials ordered the copters back in the air 49 days later without telling pilots -- or the Army's top general -- that the service's safety experts believed there was a 50 percent chance of a similar accident within a year.
•In five mysterious accidents, the Black Hawks were flying below 1,000 feet when they suddenly dove straight into the ground, killing everyone aboard. While the Army listed mechanical causes for three of the crashes, senior Army investigators say they believe radio waves, called electro-magnetic interference (EMI), were the real culprits. The other two crashes are officially unsolved, although investigators suspect EMI.
•While the Army minimizes the Black Hawk's vulnerability to radio waves, the Navy, which also uses the aircraft, has taken a far different approach. The Navy barred its first 14 Black Hawks -- bought for training purposes in 1982 -- from coming within "a significant number of miles" of radio towers for fear of accidents, a senior Navy engineer said. The precise distance is classified. The Navy later demanded that its future Black Hawks, known as Sea Hawks, be heavily shielded from electronic interference. They can now buzz radio towers with impunity.