Originally Posted by
Vzlet
Interesting coincidence indeed with XZ439. Here on the US east coast, we're fortunate to benefit from its regular performances at air shows.
439 was one of the FA2 development batch (the other being 195 IIRC) which were part way through being converted for the JTIDS upgrade at the time the FA2 was taken out of service. IIRC this included some structural mods in the rear equipment bad and of course the replacement of the old BCIU (80186-based mission computer) with the vastly more powerful "Core Computer" (I think it was a box full of PowerPC604s, but that was a long time ago!).
I don't think the Core Computer was ever given a flight clearence (hardware or its OFP) so I've always assumed Art's flying is on purely mechanical instruments with no HUD. That in turn probably means no IMC clearence because I remember that all the SHARs had an IMC clearence that required HUD and mechanical instruments to be both serviceable and in agreement with eachother.
PDR