Narrative:

Air carrier X flight XXX encountered wake turbulence on final approach to runway 22R at ord. We remained on/above GS about 2 mi behind an air carrier B737 throughout the approach. The wake turbulence event occurred inside the OM about 1000 ft AGL and consisted of a sudden but nonviolent right roll of about 30 degrees bank, which the first officer (PF) counteracted with rudder/aileron to roll back to wings level. We then experienced a second sudden but nonviolent right roll of similar intensity to the first, which the first officer again counteracted. I (PIC/PNF) then increased power to maximum, intending to command a missed approach if the turbulence persisted. The subsequent airspeed increase and relocation of the aircraft higher above the GS resulted in positive aircraft control and no additional turbulence, so I decided the approach could be continued safely. Ord tower slowed the aircraft behind us, which prompted that flight crew to ask the reason for the speed change. Tower controller replied that approach was 'really jamming me' which leads me to believe that aircraft spacing on the approach was tighter than normal. The first officer completed the approach uneventfully to a normal landing. Upon stopping at the gate at ord, I asked the flight attendant if he and the passenger were ok. He indicated that a few had been frightened, but they were all fine. The first officer and I did not have the opportunity to personally observe the passenger exiting the aircraft because our attention was focused on a secondary issue involving improper ramp procedures while deplaning passenger with engine #2 running (dc external power on MEL). 1 passenger commented on the turbulence while exiting the aircraft, stating something to the effect that we had done a good job controling the aircraft. Everybody else exited the aircraft and walked to the terminal under their own power without commenting on the conduct of the flight and no mention or appearance of injury. I received a call at home from a company customer service representative a couple days later, requesting that I shed some light on customer complaints regarding the flight described above. The representative had received reports of several passenger hitting their head, the 'cargo' door flying open during the flight, and the engine(south) failing during flight. I could not confirm or deny that anybody hit their head during the flight other than to repeat the flight attendant's statement that everybody was fine. However, I could confirm that the cargo door remained closed and both engines operated normally during our entire flight. Reporting passenger(south) may have used the phrase 'cargo door' to describe overhead bin doors, but the flight attendant did not mention overhead bins opening in-flight. The report of engine failure could be attributable to the addition of maximum power during the wake turbulence recovery and the subsequent power reduction when recovery was complete. This occurrence could have been avoided by: 1) increased aircraft spacing, or 2) flying the GS above the preceding aircraft. Pilots have little, if any, control over solution #1. Solution #2 is feasible only if pilots know the position of the preceding aircraft relative to the GS, which we do not. Flying an approach abnormally high above the GS can cause lahso clearance compliance problems at an airport like ord. The best solution to this problem is readiness when flying in trail of other aircraft.

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Original NASA ASRS Text

Title: WAKE TURB CAUSED THE FLC DORNIER DO328 TO LOSE CTL, AND REGAIN IT, AFTER ROLLING R 2 TIMES WHILE ON FINAL BEHIND A B737.

Narrative: ACR X FLT XXX ENCOUNTERED WAKE TURB ON FINAL APCH TO RWY 22R AT ORD. WE REMAINED ON/ABOVE GS ABOUT 2 MI BEHIND AN ACR B737 THROUGHOUT THE APCH. THE WAKE TURB EVENT OCCURRED INSIDE THE OM ABOUT 1000 FT AGL AND CONSISTED OF A SUDDEN BUT NONVIOLENT R ROLL OF ABOUT 30 DEGS BANK, WHICH THE FO (PF) COUNTERACTED WITH RUDDER/AILERON TO ROLL BACK TO WINGS LEVEL. WE THEN EXPERIENCED A SECOND SUDDEN BUT NONVIOLENT R ROLL OF SIMILAR INTENSITY TO THE FIRST, WHICH THE FO AGAIN COUNTERACTED. I (PIC/PNF) THEN INCREASED PWR TO MAX, INTENDING TO COMMAND A MISSED APCH IF THE TURB PERSISTED. THE SUBSEQUENT AIRSPD INCREASE AND RELOCATION OF THE ACFT HIGHER ABOVE THE GS RESULTED IN POSITIVE ACFT CTL AND NO ADDITIONAL TURB, SO I DECIDED THE APCH COULD BE CONTINUED SAFELY. ORD TWR SLOWED THE ACFT BEHIND US, WHICH PROMPTED THAT FLC TO ASK THE REASON FOR THE SPD CHANGE. TWR CTLR REPLIED THAT APCH WAS 'REALLY JAMMING ME' WHICH LEADS ME TO BELIEVE THAT ACFT SPACING ON THE APCH WAS TIGHTER THAN NORMAL. THE FO COMPLETED THE APCH UNEVENTFULLY TO A NORMAL LNDG. UPON STOPPING AT THE GATE AT ORD, I ASKED THE FLT ATTENDANT IF HE AND THE PAX WERE OK. HE INDICATED THAT A FEW HAD BEEN FRIGHTENED, BUT THEY WERE ALL FINE. THE FO AND I DID NOT HAVE THE OPPORTUNITY TO PERSONALLY OBSERVE THE PAX EXITING THE ACFT BECAUSE OUR ATTN WAS FOCUSED ON A SECONDARY ISSUE INVOLVING IMPROPER RAMP PROCS WHILE DEPLANING PAX WITH ENG #2 RUNNING (DC EXTERNAL PWR ON MEL). 1 PAX COMMENTED ON THE TURB WHILE EXITING THE ACFT, STATING SOMETHING TO THE EFFECT THAT WE HAD DONE A GOOD JOB CTLING THE ACFT. EVERYBODY ELSE EXITED THE ACFT AND WALKED TO THE TERMINAL UNDER THEIR OWN PWR WITHOUT COMMENTING ON THE CONDUCT OF THE FLT AND NO MENTION OR APPEARANCE OF INJURY. I RECEIVED A CALL AT HOME FROM A COMPANY CUSTOMER SVC REPRESENTATIVE A COUPLE DAYS LATER, REQUESTING THAT I SHED SOME LIGHT ON CUSTOMER COMPLAINTS REGARDING THE FLT DESCRIBED ABOVE. THE REPRESENTATIVE HAD RECEIVED RPTS OF SEVERAL PAX HITTING THEIR HEAD, THE 'CARGO' DOOR FLYING OPEN DURING THE FLT, AND THE ENG(S) FAILING DURING FLT. I COULD NOT CONFIRM OR DENY THAT ANYBODY HIT THEIR HEAD DURING THE FLT OTHER THAN TO REPEAT THE FLT ATTENDANT'S STATEMENT THAT EVERYBODY WAS FINE. HOWEVER, I COULD CONFIRM THAT THE CARGO DOOR REMAINED CLOSED AND BOTH ENGS OPERATED NORMALLY DURING OUR ENTIRE FLT. RPTING PAX(S) MAY HAVE USED THE PHRASE 'CARGO DOOR' TO DESCRIBE OVERHEAD BIN DOORS, BUT THE FLT ATTENDANT DID NOT MENTION OVERHEAD BINS OPENING INFLT. THE RPT OF ENG FAILURE COULD BE ATTRIBUTABLE TO THE ADDITION OF MAX PWR DURING THE WAKE TURB RECOVERY AND THE SUBSEQUENT PWR REDUCTION WHEN RECOVERY WAS COMPLETE. THIS OCCURRENCE COULD HAVE BEEN AVOIDED BY: 1) INCREASED ACFT SPACING, OR 2) FLYING THE GS ABOVE THE PRECEDING ACFT. PLTS HAVE LITTLE, IF ANY, CTL OVER SOLUTION #1. SOLUTION #2 IS FEASIBLE ONLY IF PLTS KNOW THE POS OF THE PRECEDING ACFT RELATIVE TO THE GS, WHICH WE DO NOT. FLYING AN APCH ABNORMALLY HIGH ABOVE THE GS CAN CAUSE LAHSO CLRNC COMPLIANCE PROBS AT AN ARPT LIKE ORD. THE BEST SOLUTION TO THIS PROB IS READINESS WHEN FLYING IN TRAIL OF OTHER ACFT.

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.