Quoting hotdog:
". . .from aliens to EMI to RMI. . . ."
May i remind you that a bad connection in aircraft wiring can result in EMI?
Neither the electronics nor the well shielded wiring itself but the wiring connections seem to have been problematic on occasions.
Sometimes the cause has been traced to such bad connection by disconnecting and reconnecting LRUs, solving the problem.
For example on one such incident (i stress, a different time, different plane), a MCP (mode control panel) was doing strange things intemittently like letting both pitch and autothrottle fight each other to maintain speed. Nearly all LRUs involved were changed before it was discovered that the windshield heat was not correctly grounded. This is located just a few inches from the MCP and is one of the big consumers on board. Tightening a few nuts solved the problem.
From examples like this the industry has learned over the years.
There is also a difference between a factory fresh airplane and an airplane being in service for several years subjected to the elements, and wear and tear. Good maintenance keeps things in check but EMI can be something intermittent which can only be addressed if it exists at the time of an inspection or an operational check.
Not to mention if it is a combination of signals mixing in like multiple signals from PEDs or from outside sources. PEDs also have specs but what happens to those specs if the user has dropped his PED once or twice on occasion, perhaps damaging it but is still functioning?
Now (and this is just theory) to go back to the aircraft in question and its engine feed system. What if EMI in some way had gotten hold of both spar valve control relays or open-close actuators on the valve control, mounted on the rear spar (outside of the fuselage / Faraday cage) and were temporarily closed and re-opened as the EMI appeared and disappeared. This would have restricted fuel flow to the engine pumps. What effect would that have had on pump cavitation . . . . .?
Also, i am aware that fuel "run" to "cut-off" switching would have appeared on the DFDR recording but would the DFDR also record uncommanded closure of the spar valves with the cut-off switches still in "run" position?
Regards,
Green-dot