Avionics Bending: Surface Position Indicator - Pinout

The L-1011 instrument pinout for today is for the Surface Position Indicator. It is actually quite interesting to see how different the various surface position indicators are and how much they needed to be customized to the specific aircraft. The one for the L-1011 includes all the scales for DLC since the L-1011 was the only aircraft using DLC as pitch control during approach.

The Surface Position Indicator is actually a relatively simply pointer instrument that can be driven with very low voltages. See the schematic for the Surface Position Indicator below:

Here is the pinout for the instrument:

Format: Connector | Pin | Function

SP-P1	a	Right Spoiler 6 (Y)
SP-P1	A	Instrument Lighting +5V
SP-P1	b	Right Spoiler 2 (Y)
SP-P1	B	Instrument Lighting - GND
SP-P1	C	Right Inboard Aileron
SP-P1	C	Left Spoiler 5 (Y)
SP-P1	d	Left Spoiler 4 (Y)
SP-P1	D	Left Inboard Aileron
SP-P1	E	Trim Indicator 2 -
SP-P1	L	Right Spoiler 6 (X)
SP-P1	M	Right Spoiler 2 (X)
SP-P1	N	Left Spoiler 5 (X)
SP-P1	P	Left Spoiler 4 (X)
SP-P1	R	Stabilizer
SP-P1	S	Rudder
SP-P1	T	Chassie Ground
SP-P1	U	Chassie Ground
SP-P1	V	Right Outboard Aileron
SP-P1	W	Left Outboard Aileron
SP-P1	X	Trim Indicator 2 +
SP-P1	Y	Trim Indicator 1 -
SP-P1	Z	Trim Indicator 1 +