EXWOK
The OAF 'Mach 1 glitch' was pretty much from day 1, yonks before the nose job. All we were ever able to establish was that it was definately the ALTITUDE comparator tripping the red ADS master warning I established that one during a test flight. (At FL290 you needed around 350' comparison error between ADCs for at least 3 seconds in order to trip the warning). Trouble was the error was gone so quickly you never got very far. (And the AIDS/FDR system on OAF and OAG only took readings from #1ADC, and not both as was the case with the original 5 aircraft, so the FDR was not much help either).
ChristiaanJ
The 'tubes' (there are two, side by side) are the fairings for the ADF (automatic direction finder) aerials. And IIRC, the magnetic compass sensors ('flux-valves') are under there as well.
Not on the production aircraft my friend, there was now just a single raised fairing, offset to the left of the fuselage crown which houses both ADF sense antennas as well as the 2 compass flux valves. The smaller central fairing is the one housing the ADF Loop antennas.
This view from the top of the fin shows it all quite clearly.
Best regards
Dude
