Embraer Legacy 600 (EMB135BJ)
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Engineer; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 70; Flight Crew Total 4000; Flight Crew Type 600
Confusion; Situational Awareness; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem
Aircraft
Climbing out of ZZZ; I was instructed to turn direct to ZZZ1 passing 15;000. My Altimeter in the airplane showed 15;000 and the airplane started a smart turn to ZZZ1. As soon as the plane started to turn; the Controller asked what I was doing and why I was turning. I told her that I was turning toward ZZZ1 as instructed. She then told me that I was only at 14;900. I was very confused; because my Altimeter showed 15;000. I then verified the Altimeter setting; and it was correct on all three gauges. At that point I initiated an expeditious climb to reach 15;000. The Controller and I had several back and forth discussions on the altitude. I rebooted the system on board; and after that; the altitude read correctly. The next day; I was in the same plane; and it did the very same thing to me again. This time I caught it before any terrain or compliance issues came into play. Rebooted the system; and did not have any issues after then.
Pilot was queried by Controller why he was turning his EMB-600 Legacy aircraft at 14;900 instead of 15;000 as directed. Pilot noted all three altimeters did read 15;000. They rebooted the system onboard and the altimeter read correctly. The next day the same aircraft had the same condition. They rebooted the system and no further issues arose.