Morgans wrote:
"Jerry Wass" wrote

D Instrument (other than Flight
or Engine Instruments)
DA Ammeter
DB Flap Position Indicator
DC Clock
DD Voltmeter
DE Outside Air Temp
DF Flight Hour Meter

Why not make the above items "A" for Avionics?

Well it was used by someone before, maybe it exists in some workshop
manuals--just thought if the plane was sold to a non-builder, he might
take it to an old timer that knew it,