PLT OF AN SMA SINGLE ENG LAND PVT ACFT EXPERIENCED WAKE TURB ON FINAL APCH FROM A B-757 THAT MADE APCH 4 MINS EARLIER.

Narrative

I HAD JUST BEEN TO A SAFETY SEMINAR IN RIVERSIDE WITH MY FATHER. THE SUBJECT -- 'ON LNDGS.' THE FAA PRESENTATION DEALT WITH AVOIDING LONG LNDGS; AND HOW TO MAKE A SAFE GAR. UPON OUR RETURN TO SNA; WE DECIDED TO PUT OUR UPDATED KNOWLEDGE TO GOOD USE. MY FATHER; IN ORDER TO CONTINUE HIS NIGHT CURRENCY; ELECTED TO MAKE AN EXTRA TKOF AND LNDG. FOR THIS; WE WERE GIVEN THE L RWY (19L); WITH A CTRLINE 500 FT FROM 19R; THE INST RWY. ON DOWNWIND WE WERE ADVISED OF A B-757 ON APCH TO 19R. WE HAD THE ACFT IN SIGHT AND ELECTED TO TURN BASE SO AS TO STAY WELL CLR; AND ABOVE; THE B-757 FLT PATH. WE BOTH KNEW THAT WITH CALM WINDS THE L WINGTIP VORTEX WOULD SOON LINE ITSELF UP RIGHT OVER THE L RWY BEFORE DISSIPATING. THEREFORE; WE ELECTED TO GAR. A GOOD 3-4 MINS AFTER THE B-757 ARR; WE WERE TURNING FINAL AGAIN; FOR THE L RWY. AS WE APCHED THE THRESHOLD; WE STILL ENCOUNTERED CONSIDERABLE TURB. THE AIR SMOOTHED OUT OVER THE RWY AND WE LANDED WITHOUT INCIDENT. AS A CTLR; IT IS PART OF MY JOB TO KEEP TRACK OF TIME IN CERTAIN SITS; WAKE TURB PROCS BEING ONE OF THEM. I HIGHLY RECOMMEND 2 THINGS: AS A PLT; BE EXTRA CAREFUL WHEN LNDG ON A RWY WHICH IS PARALLEL TO ANOTHER RWY BEING USED BY LARGE OR HVY JETS. WE ALL KNOW WHAT WINGTIP VORTICES DO WHEN THEY ARE CLOSE TO THE GND. STAY AWARE OF THE ELAPSED TIME BTWN YOU AND A PRECEDING LARGE OR HVY ACFT WHEN IN-TRAIL SPACING IS NOT A FACTOR; I.E.; PARALLEL RWYS; ONE RWY BEING A 'PATTERN' RWY; SUCH AS AT SNA.