Collins IND-31C GPS / VOR / LOC / Glideslope Indicator with Syncro

The IND-31C is very much like the IND-351 and IND-351A from the well-regarded Collins Microline series. The difference is that the IND-31C includes a syncro that can be slaved to an HSI's bootstrap output. The IND-31C uses two rectilinear meter movements, instead of pendulum, which makes it easier to read. This is especially nice when flying an ILS, since the needles stay perpendicular to each other. This feature helps the pilot to better determine the degree of correction needed to follow the approach accurately. This indicator does not contain a VOR/LOC Converter, which permits its use with a GPS. The IND-31C, together with an Annunciator Control Unit (ACU), can be used to meet the FAA requirements for an IFR GPS installation. The IND-31C features:

Metal case
Easy to read face
Standard ARINC interface
TSO'd

This indicator does not contain a Glideslope Receiver, so it needs that information from another source. If your NAV or NAV/COMM driving this indicator lacks glideslope, then either a Collins GLS-350 or King KN-75 remote mount Glideslope Receiver are common solutions. You may also trade your NAV or NAV/COMM for one that does contain a Glideslope Receiver. Since the Collins IND-31C does not contain an internal VOR/LOC Converter, it is designed to be used with NAV equipment that does include this converter, such as:

Collins VIR-350 NAV
Collins VIR-351 NAV
King KNS-81 NAV/RNAV/Glideslope
King KNS-80 NAV/RNAV/DME/Glideslope
King KX-165 NAV/COMM 14V (with Glideslope)
King KX-165 NAV/COMM 28V (with Glideslope)