PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 10; Flight Crew Total 4000; Flight Crew Type 500
Aircraft Equipment Problem Critical
Flight Crew Diverted; Flight Crew Landed in Emergency Condition
Human Factors; Aircraft
[I had a] possible intrusion into Class D Airspace. Aircraft was temporarily deviated from intended flight path and pilot descended from altitude due to rough engine operation. Decision was made to land when engine operation progressively got worse. Application of carburetor heat; lean mixture and abrupt change in pitch attitude temporarily resolved the engine problem. Upon landing; fuel contamination was found.
PA28 pilot reports a possible Class D airspace incursion while attempting to troubleshoot a rough running engine. The reporter elects to land at the airport in question where contaminated fuel is discovered.