While the KLN-89 and KLN-89B use the same rack, connector plate, and mating connectors, the features, functions, and subsequent installation certification need to be taken into consideration.

The KLN-89 is for VFR navigation while the KLN-89B provides VFR, IFR enroute, and IFR non-precision approach functions. For complete IFR certification, CDI and annunciators must be interfaced to the KLN-89B along with a 28 day database subscription. This is not required for the KLN-89.

For more information on IFR GPS certification and approval, please see this important FAQ here.