Narrative:

After filing an IFR flight plan for purposes of practicing multiple IFR approachs in IMC, with a ceiling allowing for much of approachs to be flown in IMC, I activated my flight plan and began receiving radar vectors from socal approach (sct) to complete an ILS into chino, ca. Cruising at 6000 ft I was on a vector towards pdz VOR when traffic, a B727 or B737 was reported 2 NM at my 10 O'clock position at 7000 ft. Even though out of the clouds for a few seconds I did not have the traffic and so reported. Sct advised the B737 of my position but the captain reported in IMC. Sct vectored me to my 10 O'clock position directly at the traffic for a few seconds and then vectored me back to the southwest on the path of the B737 with a warning of 'wake turbulence' due to the over passing B737 at 7000 ft. I believe the B737 was directed to begin its descent, but I am not sure. I had re-entered IMC with intermittent rain as I turned back towards the path of the B737. After flying a couple of mins I encountered severe turbulence which caused my plane to enter a nose-up, left turning unusual attitude. After correcting from the near stall attitude by applying power and leveling the nose and wings the plane was suddenly and violently thrown into a nose low, 50-60 degree banking right turn which was difficult to recover from. I reduced power as the airspeed increased from 65 KTS to over 130 KIAS. After retarding the throttle I leveled the wings which took some time since the plane continued to push over into the turn. With the wings level I gently pulled the nose up and the plane leveled itself. I noticed first the loss of altitude which I was correcting for as sct radioed that I was off track and flying northbound (a specific heading was advised but I do not recall it) with a request to turn back to a southwest heading towards pdz VOR. While correcting the heading deviation, sct asked if I had the plane back under control. I advised that I did. At this point I was extremely concerned about the upset, especially considering this was the first time I had flown in the clouds by myself. At the time I believed that I must have flown into cloud turbulence since just before the upset the clouds had darkened around me (later I realized the darkening clouds was probably due to the jet exhaust). My focus was intently on my instrument scan to make sure the plane remained under control while the air traffic control woman spoke to me. She asked if I had been 'reverse sensing' (from the pdz VOR) and I believe my reply was something like, 'possibly.' I was saying a prayer of thanks at that time. Cautiously I followed the remainder of sct's directions by slowly descending towards the final approach course. Since I was over 2000 ft above the final approach altitude of 3200 ft I was trying to increase the descent rate while still remaining under control. Sct then reported I had flown through the final course and turned me to re-intercept which I did. I landed without incident at chino since I was told sct was too busy for practice approachs. I returned to my home base at rialto on an IFR clearance without incident at 6000 ft in the same area the earlier upset had occurred. Only minor turbulence was encountered. Except for the upset period, I remained under control with only minor deviations of 10 degrees in heading and/or 50 ft in altitude with immediate corrections. I did not experience spatial disorientation at anytime and had felt comfortably under control throughout most of the flight(south). After the flight I was able to reflect back on the incident. I believe that I encountered the left wingtip vortex of the B737 which caused the upset to my plane. The timing and distance would have placed my plane in the path of the descending wake turbulence of the outside wing of the jet as it passed overhead. I am not sure, but I believe the jet had also just been directed to begin a descent at about the time I was flying towards its path. Beyond the fact, I had major heading and altitude deviations, which might have caused me to violate ontario class C airspace, the incident is important because the distance separating the large jet and myself was not sufficient, as evidenced by ATC's warning of waketurb and extreme position my plane was forced into. I should have refused the vector behind the jet, but at the time I felt I was being given the opportunity to practice, even though the area was fairly congested with jets into ontario with returning passenger. I also learned that I should have immediately reported to sct about the upset due to the severe turbulence even though I was not sure exactly why the upset occurred. At the time I was very relieved to have control of the plane again which, at the time, I thought was due to my inexperience causing me to be reluctant to report what had actually occurred. The air traffic controller must have recognized I had been in trouble to some extent since sct had asked me if I was back in control shortly after my upset. The proper separation appears to have been ignored due to traffic congestion. However, I could have continued my sbound vector and simply been vectored around to intercept the final course from the south instead of the north. Furthermore, my training paid-off because I was able to keep the plane upright and never felt I was totally out-of-control. I followed my training and practice by the book for both the nose-up and nose-down unusual attitudes. And, I took my time evaluating all of the instruments and continuing a complete instrument scan during the entire flight. My attitude indicator had become unreliable as it had almost turned over during the nose-down extreme right banking maneuver resulting in my reliance upon my other instruments to verify my attitude, including the turn and bank indicator, RMI, and heading indicator for the direction of the bank. Thank god for my excellent training. Callback conversation with reporter revealed the following information: the pilot was flying his PA28R-200 arrow at 6000 ft and was intent on practicing instrument approachs at chino. As he was recovering, he alleged that the approach controller was scolding him for being on the wrong heading and he turned to the new vector toward pdz. He said that he did not report the reason for his turn because he was unsure of the cause of the upset. He now thinks that he was somewhat shocked and simply complied with the controller's instructions automatically. After completing one approach the controller said that she was too busy for practice approachs. The reporter said that he was very tired and was glad to go home.

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Original NASA ASRS Text

Title: A PA28 PLT HITS THE WAKE OF A B737 AS HE WAS CROSSED UNDER AND BEHIND THAT ACFT BY A VECTOR FROM APCH CTLR. THE PLT INITIALLY HAD DOUBTS THAT HE COULD RECOVER FROM THE VIOLENT EFFECT OF THE WAKE. HE DID NOT RPT THE ENCOUNTER TO THE CTLR.

Narrative: AFTER FILING AN IFR FLT PLAN FOR PURPOSES OF PRACTICING MULTIPLE IFR APCHS IN IMC, WITH A CEILING ALLOWING FOR MUCH OF APCHS TO BE FLOWN IN IMC, I ACTIVATED MY FLT PLAN AND BEGAN RECEIVING RADAR VECTORS FROM SOCAL APCH (SCT) TO COMPLETE AN ILS INTO CHINO, CA. CRUISING AT 6000 FT I WAS ON A VECTOR TOWARDS PDZ VOR WHEN TFC, A B727 OR B737 WAS RPTED 2 NM AT MY 10 O'CLOCK POS AT 7000 FT. EVEN THOUGH OUT OF THE CLOUDS FOR A FEW SECONDS I DID NOT HAVE THE TFC AND SO RPTED. SCT ADVISED THE B737 OF MY POS BUT THE CAPT RPTED IN IMC. SCT VECTORED ME TO MY 10 O'CLOCK POS DIRECTLY AT THE TFC FOR A FEW SECONDS AND THEN VECTORED ME BACK TO THE SW ON THE PATH OF THE B737 WITH A WARNING OF 'WAKE TURB' DUE TO THE OVER PASSING B737 AT 7000 FT. I BELIEVE THE B737 WAS DIRECTED TO BEGIN ITS DSCNT, BUT I AM NOT SURE. I HAD RE-ENTERED IMC WITH INTERMITTENT RAIN AS I TURNED BACK TOWARDS THE PATH OF THE B737. AFTER FLYING A COUPLE OF MINS I ENCOUNTERED SEVERE TURB WHICH CAUSED MY PLANE TO ENTER A NOSE-UP, L TURNING UNUSUAL ATTITUDE. AFTER CORRECTING FROM THE NEAR STALL ATTITUDE BY APPLYING PWR AND LEVELING THE NOSE AND WINGS THE PLANE WAS SUDDENLY AND VIOLENTLY THROWN INTO A NOSE LOW, 50-60 DEG BANKING R TURN WHICH WAS DIFFICULT TO RECOVER FROM. I REDUCED PWR AS THE AIRSPD INCREASED FROM 65 KTS TO OVER 130 KIAS. AFTER RETARDING THE THROTTLE I LEVELED THE WINGS WHICH TOOK SOME TIME SINCE THE PLANE CONTINUED TO PUSH OVER INTO THE TURN. WITH THE WINGS LEVEL I GENTLY PULLED THE NOSE UP AND THE PLANE LEVELED ITSELF. I NOTICED FIRST THE LOSS OF ALT WHICH I WAS CORRECTING FOR AS SCT RADIOED THAT I WAS OFF TRACK AND FLYING NBOUND (A SPECIFIC HEADING WAS ADVISED BUT I DO NOT RECALL IT) WITH A REQUEST TO TURN BACK TO A SW HEADING TOWARDS PDZ VOR. WHILE CORRECTING THE HEADING DEV, SCT ASKED IF I HAD THE PLANE BACK UNDER CTL. I ADVISED THAT I DID. AT THIS POINT I WAS EXTREMELY CONCERNED ABOUT THE UPSET, ESPECIALLY CONSIDERING THIS WAS THE FIRST TIME I HAD FLOWN IN THE CLOUDS BY MYSELF. AT THE TIME I BELIEVED THAT I MUST HAVE FLOWN INTO CLOUD TURB SINCE JUST BEFORE THE UPSET THE CLOUDS HAD DARKENED AROUND ME (LATER I REALIZED THE DARKENING CLOUDS WAS PROBABLY DUE TO THE JET EXHAUST). MY FOCUS WAS INTENTLY ON MY INST SCAN TO MAKE SURE THE PLANE REMAINED UNDER CTL WHILE THE AIR TFC CTL WOMAN SPOKE TO ME. SHE ASKED IF I HAD BEEN 'REVERSE SENSING' (FROM THE PDZ VOR) AND I BELIEVE MY REPLY WAS SOMETHING LIKE, 'POSSIBLY.' I WAS SAYING A PRAYER OF THANKS AT THAT TIME. CAUTIOUSLY I FOLLOWED THE REMAINDER OF SCT'S DIRECTIONS BY SLOWLY DSNDING TOWARDS THE FINAL APCH COURSE. SINCE I WAS OVER 2000 FT ABOVE THE FINAL APCH ALT OF 3200 FT I WAS TRYING TO INCREASE THE DSCNT RATE WHILE STILL REMAINING UNDER CTL. SCT THEN RPTED I HAD FLOWN THROUGH THE FINAL COURSE AND TURNED ME TO RE-INTERCEPT WHICH I DID. I LANDED WITHOUT INCIDENT AT CHINO SINCE I WAS TOLD SCT WAS TOO BUSY FOR PRACTICE APCHS. I RETURNED TO MY HOME BASE AT RIALTO ON AN IFR CLRNC WITHOUT INCIDENT AT 6000 FT IN THE SAME AREA THE EARLIER UPSET HAD OCCURRED. ONLY MINOR TURB WAS ENCOUNTERED. EXCEPT FOR THE UPSET PERIOD, I REMAINED UNDER CTL WITH ONLY MINOR DEVS OF 10 DEGS IN HEADING AND/OR 50 FT IN ALT WITH IMMEDIATE CORRECTIONS. I DID NOT EXPERIENCE SPATIAL DISORIENTATION AT ANYTIME AND HAD FELT COMFORTABLY UNDER CTL THROUGHOUT MOST OF THE FLT(S). AFTER THE FLT I WAS ABLE TO REFLECT BACK ON THE INCIDENT. I BELIEVE THAT I ENCOUNTERED THE L WINGTIP VORTEX OF THE B737 WHICH CAUSED THE UPSET TO MY PLANE. THE TIMING AND DISTANCE WOULD HAVE PLACED MY PLANE IN THE PATH OF THE DSNDING WAKE TURB OF THE OUTSIDE WING OF THE JET AS IT PASSED OVERHEAD. I AM NOT SURE, BUT I BELIEVE THE JET HAD ALSO JUST BEEN DIRECTED TO BEGIN A DSCNT AT ABOUT THE TIME I WAS FLYING TOWARDS ITS PATH. BEYOND THE FACT, I HAD MAJOR HEADING AND ALT DEVS, WHICH MIGHT HAVE CAUSED ME TO VIOLATE ONTARIO CLASS C AIRSPACE, THE INCIDENT IS IMPORTANT BECAUSE THE DISTANCE SEPARATING THE LARGE JET AND MYSELF WAS NOT SUFFICIENT, AS EVIDENCED BY ATC'S WARNING OF WAKETURB AND EXTREME POS MY PLANE WAS FORCED INTO. I SHOULD HAVE REFUSED THE VECTOR BEHIND THE JET, BUT AT THE TIME I FELT I WAS BEING GIVEN THE OPPORTUNITY TO PRACTICE, EVEN THOUGH THE AREA WAS FAIRLY CONGESTED WITH JETS INTO ONTARIO WITH RETURNING PAX. I ALSO LEARNED THAT I SHOULD HAVE IMMEDIATELY RPTED TO SCT ABOUT THE UPSET DUE TO THE SEVERE TURB EVEN THOUGH I WAS NOT SURE EXACTLY WHY THE UPSET OCCURRED. AT THE TIME I WAS VERY RELIEVED TO HAVE CTL OF THE PLANE AGAIN WHICH, AT THE TIME, I THOUGHT WAS DUE TO MY INEXPERIENCE CAUSING ME TO BE RELUCTANT TO RPT WHAT HAD ACTUALLY OCCURRED. THE AIR TFC CTLR MUST HAVE RECOGNIZED I HAD BEEN IN TROUBLE TO SOME EXTENT SINCE SCT HAD ASKED ME IF I WAS BACK IN CTL SHORTLY AFTER MY UPSET. THE PROPER SEPARATION APPEARS TO HAVE BEEN IGNORED DUE TO TFC CONGESTION. HOWEVER, I COULD HAVE CONTINUED MY SBOUND VECTOR AND SIMPLY BEEN VECTORED AROUND TO INTERCEPT THE FINAL COURSE FROM THE S INSTEAD OF THE N. FURTHERMORE, MY TRAINING PAID-OFF BECAUSE I WAS ABLE TO KEEP THE PLANE UPRIGHT AND NEVER FELT I WAS TOTALLY OUT-OF-CTL. I FOLLOWED MY TRAINING AND PRACTICE BY THE BOOK FOR BOTH THE NOSE-UP AND NOSE-DOWN UNUSUAL ATTITUDES. AND, I TOOK MY TIME EVALUATING ALL OF THE INSTS AND CONTINUING A COMPLETE INST SCAN DURING THE ENTIRE FLT. MY ATTITUDE INDICATOR HAD BECOME UNRELIABLE AS IT HAD ALMOST TURNED OVER DURING THE NOSE-DOWN EXTREME R BANKING MANEUVER RESULTING IN MY RELIANCE UPON MY OTHER INSTS TO VERIFY MY ATTITUDE, INCLUDING THE TURN AND BANK INDICATOR, RMI, AND HEADING INDICATOR FOR THE DIRECTION OF THE BANK. THANK GOD FOR MY EXCELLENT TRAINING. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE PLT WAS FLYING HIS PA28R-200 ARROW AT 6000 FT AND WAS INTENT ON PRACTICING INST APCHS AT CHINO. AS HE WAS RECOVERING, HE ALLEGED THAT THE APCH CTLR WAS SCOLDING HIM FOR BEING ON THE WRONG HEADING AND HE TURNED TO THE NEW VECTOR TOWARD PDZ. HE SAID THAT HE DID NOT RPT THE REASON FOR HIS TURN BECAUSE HE WAS UNSURE OF THE CAUSE OF THE UPSET. HE NOW THINKS THAT HE WAS SOMEWHAT SHOCKED AND SIMPLY COMPLIED WITH THE CTLR'S INSTRUCTIONS AUTOMATICALLY. AFTER COMPLETING ONE APCH THE CTLR SAID THAT SHE WAS TOO BUSY FOR PRACTICE APCHS. THE RPTR SAID THAT HE WAS VERY TIRED AND WAS GLAD TO GO HOME.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.