BLEU's first attempt at solving the problem was to place two cables, one mile long, extending along each side of the runway, similar to the Ambrose Channel pilot cable. A detector in the aircraft could see the signal from the cables and align itself very accurately along the midline of the runway.[16] For vertical guidance, a new FM radio altimeter that BLEU developed was capable of resolving height differences to 2 feet at low altitude.[17] The team safely conducted thousands of test landings using this system.