The FLAPS DRIVE checklist directs the flight crew to :
Flaps position 5 or less :
Note: Move the FLAP lever to 1 and use VREF 30 + 40 for landing. This ensures the slats are extended.
Now, the scenario :
If the system was operating correctly in PRIMARY MODE when FLAPS 1 was selected, then the LE SLATS would extend to the MID-RANGE ( SEALED position ), then when you select FLAPS 5 the trailing edge flaps move from their up position to the 5 unit position, but during their motion the EICAS "FLAPS PRIMARY FAIL" appears, then immediately followed by "FLAPS DRIVE".
So why would you move the FLAP LEVER to the FLAPS 1 detent ?
The leading edge slats are already in the "extended" mid-range ( Sealed position ).
The last sentence of the note confuses me.
Just a note, remember the PRIMARY MODE of flap sequence for EXT is SLATS move then FLAPS and vice-versa for RET.
Looking forward to what is probably a simple answer that I can't see.
