Bonanza 36
Flight Crew Flight Engineer; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 200; Flight Crew Total 21000; Flight Crew Type 900
Human-Machine Interface; Situational Awareness
Aircraft Equipment Problem Less Severe; Airspace Violation All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Exited Penetrated Airspace; Flight Crew Became Reoriented
Aircraft; Human Factors
Approached the 5;000 base section of the Seattle class B; Student was supposed to begin the descent to avoid the airspace and continue direct to BFI. I looked at the moving map 530WAAS with current navigation chip; and crosschecked the altitude and realized the student failed to start down.  I immediately took control of the aircraft and made an immediate left 180 to return to the 6;000 foot floor airspace.  Upon examining the track on our portable Garmin 496 it appears we made a 0.3nm incursion into the airspace.I typically use the Garmin 496 for weather and basic terrain orientation since the database is out of date. The problem with the out of date database; it shows incorrect sector altitude with base of class B at 6;000.  This may have contributed to the confusion. Remainder of flight continued normally to BFI.  No traffic conflict was observed or reported. Contributing factor is configuration of the Class B airspace.
A BE36 instructor with student reported an inadvertent entry into SEA Class B; possibly due to the student using a Garmin 496 with an out of date database. A 530WAAS correctly showed the Class B floor had lowered since the 496 was last updated. An immediate 180 degree turn was initiated.