Henry Ford and others hit upon the key to mass production - interchangeable parts with each part made to drawing tolerances with sufficient accuracy that any part can fit into any 'next higher assembly' without adjustment. Today, the original idea has been refined to tight tolerances that would have delighted the early pioneers.
The slip indicator on the EADI is adjusted on the bench as part of final assembly after manufacture or repair. When installing an EADI into the instrument panel we don't have any of those circular clamps any more! The replacement EADI slides into place on a fixed tray and locks into position using a locking lever, the handle of which you can see across the top of the display unit. Once the unit is locked into place the lever is secured in position by two fastening screws, one each side. Because every EADI and every tray are exactly the same as the next pair - within extremely tight interchangeablility tolerances - the EADI needs no adjustment after replacement.
And yes, we DO perform accurate alignment checks when replacing a whole instrument panel or its mountings. Pilots are always very welcome to come and watch...
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Through difficulties to the cinema
Last edited by Blacksheep; 17th June 2002 at 08:21.