Craig
Cleared for Takeoff
Zantop Air Transport operated an aircraft called the AW-650 Argosy. This British cargo aircraft used British Standard and Whitworth Standard hardware extensively.
It utilized screws that were slotted. However; there was also a drilled hole in the center of the slot. The crew always used standard flat screwdrivers but I have wondered if there was a special bit that used the hole to stabilize the bit.
May have been a copy of Sony's "Slot and Dot" screw style. Slot head screw with a hole drilled on the center line. The driver was a slot head style with a spring loaded half pin to fit in one side of the hole. That gave the driver the capability of holding the screw prior to insertion, or retaining it on removal.