An airline pilot; recently reintroduced to general aviation and flying a light sport aircraft; wrongly assumed the GPS would warn him before he climbed into Class B airspace.

Narrative

I have been flying for the airlines for 28 years. I have recently gotten back into general aviation flying. My how things have changed! I love the GPS and its ability to warn me of airspace ahead. What I didn't realize is that the GPS doesn't protect me from CLIMBING into airspace. I was flying VFR on a flight for enjoyment. I was watching the Class B airspace above me. I assumed that the airspace started at 4;000 FT. I decided to climb to 3;500 FT. I had some time to play with the GPS so I checked nearest airspace and it informed me that I was inside class B airspace. The GPS was so good about warning me about airspace ahead that I assumed it would advise if I was climbing toward airspace. The funny thing is that if I didn't have the GPS; I would have been much more aware about the airspace. Since I had the GPS; I trusted it way more than I should have. I was monitoring 121.5 and nobody called to me so I assume there were no traffic conflicts. Other than embarrassing myself there was apparently no harm.