Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 120; Flight Crew Total 34500; Flight Crew Type 350
Aircraft Equipment Problem Less Severe; Airspace Violation All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Exited Penetrated Airspace; Flight Crew Overcame Equipment Problem
Aircraft
During an ILS instrument approach to TYQ RNW 36 we lost the Primary Flight Display (PFD) resulting in loss of data from GPS temporarily.  The aircraft was positioned parallel to the Class C airspace of IND in a position I believed to be just north of IND Class C by reference to visual points on the ground.  I instructed the student to fly 10 degrees further north of the Class C airspace.  After reset of the PFD my flight track showed on the northern edge of the Class C IND airspace at 2700' MSL.  My command to turn further left to a heading of 080 had us clear of Class C.  I believe we may have been inside Class C airspace by approximately .1 to .2 nm for approximately less than 1 minute.  I had visual reference to a light twin about 600' below and 1-2 mi east of my position on an approach to EYE. We had no traffic advisory and no separation standards were compromised. We proceeded to TYQ without incident.
Instructor Pilot reported an airspace violation related to loss of the Primary Flight Display and GPS data.