Free Acid Sky by Mark Anson

very end of the carrier, located behind the unpressurised main hangar, and occupied a large space about forty metres across each way and seven high. A closed set of large pressure doors sealed off the entrance to the main hangar, and the two end corners were cut off by curving walls where Clare guessed the refineries lay. The entire space was filled with Frigate aircraft in various stages of repair and overhaul. Hoses and cables snaked across the floor to where technicians worked on the aircraft, and the intermittent sound of an impact wrench punctuated the banging and crashing noises of a busy maintenance operation.
    With a whine of electric motors, an access platform lowered from above them, and the maintenance chief leaned over the side.
    ‘Mind if we take a look around?’ Coombes shouted up.
    ‘Go ahead. Just stay clear of anything that moves, we’re about to power up the hydraulics.’ The chief leaped off the descending platform and walked off towards the nose of the nearest aircraft, which was raised off the deck on support frames, its landing gear hanging in the air.
    ‘Major maintenance check,’ Coombes commented. ‘They’re up against the clock because we've always got to keep a minimum of eight aircraft in serviceable condition.’
    Clare nodded. She was still taking in the scale of the operation, and she had to keep reminding herself that this hangar wasn’t on the ground, but flying along in the skies of Venus.
    Red warning lights started flashing, and there was a sharp hiss of compressed air. A loud whine of electrically-powered hydraulics broke out close by, and Coombes and Clare stepped backwards instinctively as the folded wingtip of the aircraft started to move. It swung up and over in a graceful arc until it stopped in its flight position, and there was a clunk of metal pins sliding home to lock the wing in place.
    Underneath the aircraft, the nose and main landing gear lifted up into their bays, and the doors closed over them. Then the sequence reversed, and the doors opened and the landing gear lowered again and locked in place. The chief stood off to one side with his arms folded, watching the test with a group of technicians, and finally signalled for the systems to be powered down.
    The red lights stopped flashing, and Coombes and Clare walked under the right wing and round to the rear of the craft. The painted finish on the underside of the Frigate was dirty and worn in places from countless landings. She stopped, and ran her finger over the exposed metal.
    ‘What do you do about corrosion?’
    ‘Huh?’
    ‘Corrosion – from the acid in the air.’
    ‘Oh – well the metal's a special alloy to resist corrosion, but it’s not really a problem at this altitude in any case, as the concentration’s so low. They get regular checks for corrosion on critical components, and a wash down every so many flying hours. The biggest corrosion problem is the carrier structure itself, as it has to go deep into the clouds every night to mine the air.’
    ‘So what do you do? About the carrier I mean – you can’t go outside to inspect it.’
    ‘No, but it’s so big that most of the critical parts of the airframe – the wing spars and so on – can be inspected from the inside. The outside skin though, well that’s just got a service life. It’s supposed to last longer than the reactors will, at least in theory, so it shouldn’t matter. It’s too early to tell, really.’
    Coombes paused, and looked round the maintenance hangar, then back at Clare. ‘You seen enough?’
    ‘Sure.’
    They walked back to the airlock, raising a hand to the chief as they left the hangar.
    ‘Where next?’ Clare asked as they stepped out into the lower main corridor again.
    ‘The refinery. Don’t look like that, you’ll love it. It’s my favourite place.’
    Clare smiled and shook her head as they walked along the corridor towards the rear of the aircraft, a steady roar growing on their left. Coombes stopped