BOTH GENERATORS OF LR 24 TRIPPED OFF LINE CAUSING THE IAS; THE AFDS; AND ALT HOLD TO FAIL. AN ALT DEVIATION RESULTED AS THE ACFT CLBED UNNOTICED BY CREW DURING TROUBLESHOOTING.

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FLT ORIGINATED IN ZZZ ON AN IFR CLRNC AND FLT PLAN TO ZZZ2. ACFT WAS CLRED BY CTR TO FL330. ACFT WAS FLOWN BY USAGE OF ITS AUTOPLT AND THE CAPT HAD LEVELED OFF AT TARGET ALT AND ENGAGED THE ALT HOLD WHEN THE L/H GENERATOR DROPPED OFF-LINE. IMMEDIATE RESET PROC OF THE FAILED GENERATOR TRIPPED THE R/H GENERATOR OFF-LINE AS WELL AND THE CREW NOTICED THE ELECTRONIC DISPLAYS OF BOTH DIGITAL ALTIMETERS FLICKERING WITH THE #1 ALTIMETER INDICATING A RAPID DESCENT AND THE #2 ALTIMETER SHOWING A RAPID CLB. CAPT ADDRESSED THE ELECTRICAL POWER LOSS AND THE SIC WAS INVESTIGATING THE CB PANELS AND SWITCHES FOR THE ADC ON HIS SIDE. MOMENTS LATER THE CAPT ADVISED THE SIC TO WATCH THE ACFT AND STOP THE TROUBLESHOOTING ON HIS SIDE. THE 3RD STBY ALTIMETER ALSO HAD WANDERED AND FLUCTUATED BETWEEN GOING UP AND DOWN DURING THE PREVIOUSLY DESCRIBED SEQUENCE. WHILE THE CAPT SUCCESSFULLY RESTORED ELECTRICAL POWER AND GOT BOTH GENERATORS BACK ON LINE; THE SIC NOTICED AND RPTED THAT THE AUTOPLT HAD TRIPPED OFF-LINE (POTENTIALLY AS A RESULT OF THE ELECTRIC SPIKES IN THE SYSTEM FROM RESET ATTEMPTS OF THE GENERATORS). CROSS CHECKS OF BOTH VSI'S CONFIRMED A CLB AND THE PLANE SEEMED TO HAVE DEPARTED FROM THE LEVEL ALT DURING THE TROUBLESHOOTING AND SYSTEM RECOVERY PROC. THE CAPT ARRESTED THE CLB AND STARTED A SHALLOW DSCNT WITH REFERENCE TO THE STBY ALTIMETER THAT HAD STARTED TO STABILIZE AND SHOWED A FEW HUNDRED FEET ABOVE THE ASSIGNED FL330. AT OR ABOUT THAT TIME ATC CALLED AND ASKED FOR ALTITUDE VERIFICATION. WITH POWER RESTORED; BOTH DIGITAL ALTIMETERS ALSO WENT BACK TO NORMAL INDICATION AND SHOWED THE SAME VALUES. CAPT LEVELED OFF AT FL330; RE-ENGAGED THE AUTOPLT AND ALT HOLD AND VERIFIED THAT BOTH GENERATORS WERE PUTTING OUT THE REQUIRED ELECTRICAL POWER. BOTH DIGITAL ALTIMETERS AND THE STBY ALTIMETERS SEEMED TO BE IN AGREEMENT AND STABLE. A FEW MINS LATER THE SIC RECEIVED A CALL FROM ATC AND A PHONE NUMBER TO CONTACT AFTER LNDG. SUBSEQUENT PHONE CONVERSATION WITH ATC AFTER LNDG REVEALED THAT THE PLANE HAD CLBED ABOVE THE ASSIGNED ALT BY SEVERAL HUNDRED FEET DURING THE TIME WHERE THE CREW WAS BUSY WITH TROUBLESHOOTING AND SYSTEM RESTORATION EFFORTS. REASONS FOR THE DEVIATION AND CONTRIBUTING FACTORS: ELECTRICAL FAILURE OF BOTH GENERATORS IN SHORT SUCCESSION AND A POTENTIAL ELECTRICAL SPIKE IN THE SYSTEM THAT TRIPPED THE AUTOPLT AND CAUSED THE ELECTRONIC ALTIMETRY SYSTEM AND THE ADC'S TO BECOME TEMPORARILY UNRELIABLE. CREW WAS DISTRACTED FOR A MOMENT AND FOCUSED TOO MUCH ON SYSTEMS RECOVERY AND DID NOT IMMEDIATELY NOTICE THE TRIPPED AUTOPLT AND THE DISENGAGED ALT HOLD BUTTON. BOTH CREW MEMBERS CHKED AND TROUBLESHOT THEIR RESPECTIVE SIDES OF THE COCKPIT AND CB BANKS (LOWER SIDE PANELS/HEAD DOWN) WITHOUT NOTICING THE PLANE'S DEPARTURE FROM THE ASSIGNED ALT QUICKLY ENOUGH. BOTH PLTS SUB-CONSCIOUSLY ASSUMED THE PLANE ON ALT HOLD AND STABLE WHICH WAS A MISTAKE SINCE IT DOES NOT TAKE LONG FOR A LEAR JET TO CLIMB A FEW HUNDRED FEET. LESSONS LEARNED FROM INCIDENT: STRICT ADHERENCE TO CRM PROCS WILL AVOID SIMILAR SITUATIONS. WITH ONE PLT FLYING AND MONITORING ATTITUDE; ASSIGNED ALTITUDE AND HEADING AND THE OTHER PLT ENGAGING IN TROUBLESHOOTING WILL PREVENT ANY DEVIATION FROM HAPPENING. HISTORY HAS SHOWN OVER AND OVER AGAIN THAT NOTHING IS HELPED IF BOTH PLTS TRY TO CURE A PROBLEM AND NOBODY WATCHES THE PLANE. BOTH CREW MEMBERS REGRET THIS INCIDENT AND WILL WORK ON PROPER CRM TO AVOID ANY SUCH FUTURE SITUATION. MECHANICAL FINDINGS: MECHANICS FOUND THE FIELD/COIL WIRES OF BOTH GENERATORS AS HAVING INTERMITTENT CONTACT. THE ACFT HAD UNDERGONE AN LH ENGINE SWAP AND SEVERAL COMPONENTS OF THE OTHER ENGINE WERE REMOVED; TESTED AND REINSTALLED PRIOR TO THE FLT. A TEST RUN AND FLIGHT HAD SHOWN NO PROBLEMS BUT SOME WIRES WERE CHAFING ON THE SUBSEQUENT FLT. THE FAULTY WIRES WERE IDENTIFIED AND REPAIRED AND THE PROBS HAVE BEEN CORRECTED.