I don't think commercial grade '286s would have been considered for use in avionics back in the '80s, they would probably have been the full Mil Spec (MIL-STD-883C compliant) versions subjected to burn in and extended inspection and testing compared with commercial parts. No idea what would be used in current production, but the industry has generally been forced to become much more reliant on COTS (commercial off the shelf) parts.