The designation for an upgraded cockpit built into the VF-1 Valkyrie variable fighter. The Block 6 system signifcantly simplified the HMI (Human-Machine Interface) for the VF-1 Valkyrie and improved the flight control with a true HOTAS system (Hands-On-Throttle-And-Stick). The Block 6 system introduced the single-panel main display and also improved target tracking/acquisition using an advanced holographic/volumetric imaging system inside the cockpit canopy. Most importantly, the Block 6 cockpit placed the variable fighter transformation control on the left stick, allowing the pilot to change vehicle modes by shifting the throttle laterally. The Block 6 cockpit was so successful that many elements of the control system are still found in the most modern variable fighters.