Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 20; Flight Crew Total 2082; Flight Crew Type 185
Situational Awareness
Airspace Violation All Types; Inflight Event / Encounter VFR In IMC; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport
Human Factors; Weather
I departed airport VFR for a short flight to LNC.  Both airports reporting MVFR with ceilings of 2;000.  I entered the traffic pattern at LNC; and was turning downwind.  The cloud base fell to 700 AGL and I entered the clouds.  I did not descend further due to hearing a Bonanza reporting base in front of me; which I could not see.  I decided the safest course of action was to climb and contact Approach for a pop up clearance and return to departure airport.  I contacted Approach and requested an IFR clearance.  I was asked if I could remain VFR; which I responded negative; that I was IMC at this time.  I was continuing to climb and must have gone through 4;000 FT (base of Class B).  I was told that I was in Class B airspace; that I was cleared into Class B airspace; to maintain 4;000 FT and given radar vectors for the GPS approach at [home airport]. The return and rest of approach was uneventful.  At the final approach fix I was in visual conditions and cancelled my clearance and thanked the controller for his assistance.
M20J pilot reported returning to departure airport after encountering IFR conditions at his destination.