At the truck she loaded the shopping then took a long rod from behind back panel of the cockpit. The rod had a moulded handle with a long metal shaft and a hammerhead at the end. She tapped the hammer on her heel then climbed out into the layby hanger.
Charlie walked around the nose of stationary vehicle, to the front wheel on the passenger side and hit the wall of tyre three times with the long neck hammer. Then she struck the rim and it pinged like a tuning fork. She held the corner of her phone to the singing rim and measured the tone. The phone screen blinked and showed her a green tick. She nodded and moved down to the next wheel and repeated the ritual; hit the tyre, strike the rim, listen and so on until she was back where she began. Only one wheel needed extra attention. The second tyre on the rear row sounded slightly hollow, and sure enough when she checked the pressure it was lower. She dragged a crane hose over, squirted air into that wheel until it was marginally higher than normal. She finished returned the rim hammer to it's place in the cab and pulled a fold away lever above the doorway. There was a hydraulic sigh and a soft but heavy click.
Charlie got down again and unfolded some steps which had been released from the smooth fuselage. The steps acended to reveal a small utility cabinate. Inside where two large white plastic vessels. The material was mostly opaic withe a thin translucent window that indicated volume. One of the tanks was darker then the other and had a bio waste logo embossed on the side.
Charlie pulled a small forklift from an neat shelf and detached the large sewage tank. She wheeled if away from the truck into a loading area. The same loading area had an empty tank identical to the full one. Charlie took an emtpy tank and reseated it into the utility compartment.
Then she climed the short steps up to a screw lid which was protuding from the second tank. She clipped a pipe to the open funnel and filled it with water, and then closed and sealed the utility area and walked down to a small office area at the exit to the static stations hanger zone.
Anything else, and attendant asked
Charlie shook her head.
Stay safe, said the attendant.
Charlie nodded and left.
She climed into the rig and closed the door and looked out across the lot to the massive empty shopping mall and sighed.
The rain pelted down like stones on the corregated roof of the static station and when the door to the truck closed the noise of the world went still.
Charlie sighed again.
She sat for a moment then leaned forward pressed a button and the truck was alive instantly, humming with colossal power of its electric dynamo. Charlie tapped the screen, flicked and poked and tapped again, then sat back in the machine moved forward with the grace of a whale and slipped thought the hanger and arc round and past the mall accelerating to join the main vein the headed north, it hit the on ramp and slipped into the first lane at 40 miles per hour.