SWITCH POS LEADS TO TRACK DEV LEADS TO LTSS.

Narrative

ON APR/WED/95 AT APPROX XA00 I DEPARTED VNY ARPT IN AN A- 36 BONANZA ON AN IFR SID-GLENDALE 7 DEP. THE GLENDALE 7 DEP CALLS FOR MAINTAINING RWY HDG UNTIL 1.5 DME AT OR BELOW 1700 FT; AND THEN A L TURN TO A 110 DEG HDG FOR VECTORS TO THE VNY R-095. AFTER TKOF AND PASSING 1.5 DME AND APPROX 1200 FT; I STARTED MY TURN TO A 110 DEG HDG. THE CTLR CALLED RADAR CONTACT AND I ACKNOWLEDGED HIS CALL. I THEN LOOKED INTO THE COCKPIT AND SAW THAT ONE VOR WAS READING TO AND THE OTHER WAS READING FROM THE STATION. I ATTEMPTED TO CTR THE HSI VOR NEEDLE AND ALSO THE OBS. I THEN BEGAN TO WONDER IF I HAD AN HSI FAILURE OR JUST A VOR FAILURE. DURING THIS TIME I HAD ALLOWED MY HDG TO DRIFT TO THE L TO APPROX 097 DEGS. I LOOKED OUT TO THE L AND SAW A LARGE COMMERCIAL ACFT; 757/767 PROBABLY ON AN APCH INTO THE BUR ARPT; APPROX 1 NM HORIZ AND 500- 700 FT VERT ALT SEPARATION. AS I STARTED TO MAKE A TURN AWAY TO THE R. THE CTLR CALLED ME FOR AN IMMEDIATE R TURN TO A HDG OF 160 DEGS. I IMMEDIATELY COMPLIED WITH THE TURN TO 160 DEG HDG. AFTER THE NEXT CALLED TURN TO ON COURSE; I ASKED THE CTLR TO VERIFY MY COURSE SO I COULD DETERMINE IF THE #2 VOR WAS OPERATING PROPERLY. IT WAS DETERMINED THAT IT WAS OPERATING PROPERLY AND THE REMAINDER OF THE FLT WAS COMPLETED WITHOUT INCIDENT. POSTFLT INVESTIGATION REVEALED THAT THE GPS/VOR PUSH-TILE WAS IN THE GPS POS CAUSING THE #1 VOR TO GIVE ERRONEOUS INDICATIONS. DUE TO THE SITTING HT OF THE PLT; THE UNDER THE GLARE SHIELD LOCATION OF THE GPS/VOR PUSH-TILE; AND THE GPS/VOR ENUNCIATOR LIGHT BEING DIM; THE PLT DID NOT NOTICE THE LIGHT/SELECTION; WHICH WAS THE CAUSE OF THE VOR FALSE FAILURE; AND THE ULTIMATE CAUSE OF THE INCIDENT. RECOMMENDATIONS: 1) THE PLT BE MORE ATTENTIVE IN ENSURING PROPER SET UP AND IDENT OF NAVAIDS; AND MONITORING HDGS WHILE TROUBLE-SHOOTING COCKPIT DISCREPANCIES. 2) SINCE BOTH ACFT WERE IN CLOSE RADAR CONTACT; ANY TIME THERE IS ANY DEV IN HDG IN HIGH DENSITY AREAS; THE CTLR IMMEDIATELY CORRECT THOSE DEVS.