LEAR60 FLT CREW REPORTS DUAL BLEED AIR LIGHTS AT FL430; LIGHTS GO OUT AS POWER IS REDUCED FOR DESCENT. ALT DEV OCCURS AT FL400 WHEN AUTOPILOT DOES NOT CAPTURE.

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CRUISING AT FL430 I HAD BOTH RED BLEED AIR LIGHTS ILLUMINATE. I THEN ASKED CTR FOR A LOWER ALT TO 10000 FT DUE TO A POSSIBLE BLEED AIR LEAK IN THE TAIL CONE AREA; WHICH COULD POSSIBLY CAUSE A FIRE. I THEN RAN THE CHKLIST FOR PROPER PROC. A COMBINATION OF LOWER PWR SETTING AND LOWER ALT LOWERED BLEED AIR TEMP IN THE TAIL CONE DUCTS EXTINGUISHING THE BLEED AIR LIGHTS. CTR GAVE US A DSCNT FROM FL430 TO FL410; FOLLOWED BY A DSCNT TO FL400 UNTIL CLR OF OPPOSITE DIRECTION TFC. I HAD A VISUAL ON TFC AT FL390. THE AUTO ALT CAPTURE DID NOT CAPTURE FL400. I THEN MANUALLY CLBED THE ACFT BACK TO FL400. AFTER A LOSS OF APPROX 300 FT; I DID NOT DECLARE AN EMER. IN RETROSPECT I SHOULD HAVE. BLEED AIR LIGHTS ARE A SERIOUS PROB. EVEN THOUGH I WAS ABLE TO SEEMINGLY CONTAIN THE PROB; DECLARING AN EMER WOULD HAVE GIVEN ME MORE ROOM TO MANEUVER IF NEEDED. I WILL NOT HESITATE TO DO SO IN THE FUTURE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE BLEED LIGHTS DID NOT COME ON AGAIN DURING THE DESCENT; BUT SINCE A BLEED AIR LEAK WAS SUSPECTED; THE ACFT WAS DIVERTED FOR MAINTENANCE. A PNEUMATIC SEAL IN THE TAIL CONE AREA WAS FOUND TO HAVE FAILED AND WAS REPAIRED.