Preliminary data said engines 12 and 24 hd shut down, and instead of firing longer to compensate the remaining 28 had all shut down early. The investigation deepened to focus on KORD. It turned out that electrical interference manifested as an erroneous signal from KORD to shut down engine 12, triggering shutdown of its opposite, engine 24, to retain symmetry. As the rocket flew higher, vibrations tore off a gas pressure-measuring pipe in the turbo pump and broke a fuel pressure pipe in engine number 2. This sent hot kerosene flowing into the base of the rocket, triggering a rise in temperature in engines 3, 21, 22, 23, and 14. The fire destroyed insulation covering power supply cables. This was interpreted by KORD as pulses in the turbo pumps, which sent the command to shut down all engines. The signal traveled up the rocket to freeze the engines in Blocks B and V, too.