A C172 pilot-rated passenger seated in the back seat described a wake vortex encounter on landing at LGB that almost resulted in an accident.

Narrative

Three friends; all airline/instructor pilots (ATPL holders) rented a Cessna 172S for a day of fun flying including attending an airport party. On the return flight home; the Tower instructed us to make left traffic Runway 25L. The pilot flying entered the downwind on the 45; at TPA. Tower advised he would 'call the base' as an A320 was on the visual/ILS Runway 30. Tower told us to turn base (and ridiculed our downwind distance as being too far out; however; all three pilots confirmed our aircraft was in the correct position relative to the runway; in case of engine failure etc). On final for Runway 25L we observed the Airbus A320 land beyond Runway 25L. I; acting as 'check pilot from the backseat;' cautioned the pilot flying for wake turbulence. The pilot flying acknowledged this; but took no action. At 50 FT AGL; the Cessna 172S encountered the first vortex. The pilot flying was able to immediately recover the wing drop with only 10 FT to spare. That was when the aircraft encountered the second vortex. Both the Tower-Local Controller and the pilot flying share blame. First; the Tower-Local Controller for calling the base too early; second; the pilot for having seen the landing position of the Airbus A320 and not flying a higher glide path to avoid the possible wake. All 3 airline pilots; who also teach GA flying with over 45;000 flying hours in total; could have been killed.