Date: 201205
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Learjet 45
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Electrical Distribution
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Situational Awareness; Time Pressure; Troubleshooting; Distraction; Communication Breakdown; Workload
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action; Flight Crew Landed in Emergency Condition; General Declared Emergency; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On departure APU assisted 2-engine start was uneventful. During taxi; a passenger request to return rental car keys to FBO resulted in a #1 engine shut-down to hand keys over to line personnel. Restart of #1 was uneventful. Taxi to the runway hold line was followed by an approximate 10 minute wait for ATC to re-route our departure for weather about 50 miles west of the airport. Following takeoff; and during the first level off and power reduction at 3;000 FT AGL; the 'GEAR' warning annunciator and CAS message began (thrust at below 65% N1). The indication was inconsistent; so we tried to identify a configuration cause; with no success. We began to assume this was related to an EGPWS/TAWS anomaly. During re-application of thrust; the annunciator ceased and CAS extinguished. During the next level off and power reduction (thrust at about 75% N1 - we were trying to identify a corresponding thrust setting) the 'GEAR' warning annunciator and CAS message returned. A quick review of the Emergency 'GEAR' checklist provided no guidance and after some discussion; we decided that since the condition only existed during power reductions; a cycling of the landing gear might quiet the (very loud and distracting) annunciator. We extended the landing gear; which functioned and indicated normally. We then retracted the landing gear which functioned and indicated normally; and the annunciator ceased. We continued the climb; to next level-off and the 'GEAR' annunciation returned. We began to discuss whether we should extend the landing gear; ensure it was down and locked and return to the departure airport; but with a realization that we were about 1;000 LBS plus overweight for landing; that it might be more advantageous to continue flight and notify Company Maintenance of our condition and see if they could obtain some guidance and help us to decide on best course of action. At about this time; we got our first 'L ESS BUS VOLTS' caution annunciator; which remained for a few seconds and cleared. Once level at FL240; we received another 'L ESS BUS VOLTS' caution and a corresponding amber 22VDC indication on the LH GEN EICAS display. With the 'GEAR' annunciation continuing; we initiated the 'L ESS BUS VOLTS' checklist. While setting up for this checklist; we noted that the L ESS VOLTS were in [a] fast decline; ticking down .1 volt about every 2 seconds. We discussed this condition and decided we would need to begin deciding on an immediate diversionary airport. We notified ATC of our condition. When asked if we were declaring an emergency; PIC responded to the effect that we were not yet in an emergency situation; but that it looked as though we may need to declare an emergency soon; as at this time some systems were beginning to drop offline. About this time; we had an 'ENTRY DOOR' warning annunciator and CAS message; which; although largely distracting; we assumed was part of our electrical anomaly. Other systems dropping offline included indications of a SPOILERS FAIL; so we asked for a vector to preferably a large airport with long runways. We were told that a major airport complex was 60 miles to our 3 o'clock; so we began the turn. We then lost COM #1 (---- dashes on RMU 1). While we tried to determine how we should recover our Center frequency from COM1 and move communications to COM2; we decided to initiate an emergency controlled descent into the divert area. It then became clear we would be better off to concentrate on completing the 'L ESS BUS VOLTS' checklist to recover our failing systems. While running this checklist; we did mistakenly pulled the L ESS BUS circuit breaker (checklist called for a 'Set;' which may have lead us to think 'Reset'). This immediately removed power from a number of items; including the autopilot; both display units on the left side (pilot side) and the pressurization system. This led to our transferring controls to the co-pilot side (working displays); donning of crew O2 masks (precautionary) and increasing the descent into the divert airport in an attempt not to allow the cabin pressure altitude to exceed 10;000 FT. We then leveled off to 9;500 FT MSL; as systems began to return to normal; including the return of radio control. We called Approach to give them our position and intentions; requesting final vectors to divert airport runway in use. We then began to run the remaining checklists to clear CAS caution items which might improve our landing performance; including resetting the nose wheel steering computer (which we noted had a 'popped' circuit breaker at that time) and the spoiler/spoilerons. Other checklists were run before landing; but we are not readily recalling each individual one at this time. We then landed without incident and proceeded to an FBO to inform company of our situation and begin finding alternate transportation back for our passengers. The Company dispatched a team to meet the aircraft first thing the next morning. No cause of the electrical system anomaly has been identified; however; a contactor in the power distribution panel has been replaced (was suspect; so as a precaution) and the 2 Data Acquisition Units have been 'swapped' side-to-side to help intensify the cause if this same condition were to develop again.




Synopsis: A LR45 GEAR warning annunciated after takeoff with each power reduction during climb and while troubleshooting that anomaly the L ESS BUS VOLTS caution alerted with an amber 22 VDC; so an emergency was declared and the flight diverted to a nearby airport.