Officially called the D20 Heavy Lift Vehicle, unofficially called 'Big Brick' by UNSC personnel, the D20 Heron is a seven-story tall flying warehouse with eight fusion engines for propulsion. It's original purpose was to airlift Colony Starter Units, which were quite on the nose for their purpose. The UNSC would later use modified versions of these Colony Starter Units as Firebase Modules for rapid deployment of ground forces. D20 Herons would also be able to ferry supplies, personnel, and even armored vehicles en masse once enough of a military presence was on the ground. Due to the engine layout (4 outboard tilt engines with another 4 fixed at the rear), the D20 was surprizingly nimble for its size, both in atmosphere, and in vacuum.

Controls:

Pitch/Roll/Yaw: Standard Control Schemes, (See AG8 for details)

Throttle: Lift Engine Power (around 87% will allow a gentle takeoff)

VTOL: Forward/Reverse Thrust (Overrides lift engine pitch controls regardless of flight mode)

AG8: Switch Flight Mode (Automatically deactivates above 280 MPH)

*AG8 ON: Hover Mode (gyroscopic stabilizer will keep the craft level, Lift engines will swivel with Pitch/Roll/Yaw)

*AG8 OFF: Forward Flight Mode (gyroscopic stabilizer disabled, craft will handle like fixed wing aircraft, lift engines will behave slightly differently due to Mark II Avionics package)

Additional Notes:

• The engine nacelles will slightly canter outwards when close to the ground with the landing gear raised.

• Avionics require landing gear to be retracted, and altitude to be at least 15 meters above the ground to function properly.

• Due to the craft's weight, the landing legs might appear to slightly ''snap'' underground. However, due to the weight of the canonical craft being 4,334 metric tonnes, this is not a bug, it is a feature.

• The Mark II Avionics package will automatically disable the gyro when travelling above 280 mph. (You can still override the system manually.)

• The Mark II Avionics package allows the outboard engine nacelles to move with several combinations of Pitch, Roll, Yaw, and VTOL while in 'fixed wing' flight mode. (Including an alternate movement pattern when using the nacelles as retro thrusters)