Narrative:

The captain was flying the leg and on short final into O'hare international runway 9R. Severe wake turbulence was encountered at less than 100 ft AGL. The aircraft rolled into an approximately 45 degree left bank and the nose pitched down. A go around was executed and subsequent approach to runway 4R was executed without incident. It is unknown what type of aircraft we were following. However spacing looked adequate visually and the entire approach was flown approximately 1 1/2 dots high on GS. In my opinion, the only method of prevention would be greater spacing between aircraft, especially following heavy aircraft. Several passenger were irate because no PA was given as to reason for our aborted landing. PA was not possible due to heavy workload with another immediate visual approach. In retrospect, a PA should have been made upon arrival at gate. Callback conversation with reporter revealed the following information: the reporter was the first officer on a bae ATP that hit the wake of a B727 and had to make a go around and an approach to another runway. The first officer seemed to be more focused on the fact that he did not make an announcement explaining the event to the passenger than on the dynamics of the wake and its avoidance. He admitted that the B727 may have been as little as 2 mi ahead of them during the approach and he felt that this was normal. The ATP's TCASII equipment was inoperative on this flight and he had to visually estimate his distance behind the B727. However, he stated that the B727 was just turning off of the runway when they hit the wake over the threshold.

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Original NASA ASRS Text

Title: AN ACR BAE ATP FLC HIT THE WAKE OF AN ACR B727 DURING THEIR APCH AND FO EXECUTED GAR.

Narrative: THE CAPT WAS FLYING THE LEG AND ON SHORT FINAL INTO O'HARE INTL RWY 9R. SEVERE WAKE TURB WAS ENCOUNTERED AT LESS THAN 100 FT AGL. THE ACFT ROLLED INTO AN APPROX 45 DEG L BANK AND THE NOSE PITCHED DOWN. A GAR WAS EXECUTED AND SUBSEQUENT APCH TO RWY 4R WAS EXECUTED WITHOUT INCIDENT. IT IS UNKNOWN WHAT TYPE OF ACFT WE WERE FOLLOWING. HOWEVER SPACING LOOKED ADEQUATE VISUALLY AND THE ENTIRE APCH WAS FLOWN APPROX 1 1/2 DOTS HIGH ON GS. IN MY OPINION, THE ONLY METHOD OF PREVENTION WOULD BE GREATER SPACING BTWN ACFT, ESPECIALLY FOLLOWING HVY ACFT. SEVERAL PAX WERE IRATE BECAUSE NO PA WAS GIVEN AS TO REASON FOR OUR ABORTED LNDG. PA WAS NOT POSSIBLE DUE TO HVY WORKLOAD WITH ANOTHER IMMEDIATE VISUAL APCH. IN RETROSPECT, A PA SHOULD HAVE BEEN MADE UPON ARR AT GATE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS THE FO ON A BAE ATP THAT HIT THE WAKE OF A B727 AND HAD TO MAKE A GAR AND AN APCH TO ANOTHER RWY. THE FO SEEMED TO BE MORE FOCUSED ON THE FACT THAT HE DID NOT MAKE AN ANNOUNCEMENT EXPLAINING THE EVENT TO THE PAX THAN ON THE DYNAMICS OF THE WAKE AND ITS AVOIDANCE. HE ADMITTED THAT THE B727 MAY HAVE BEEN AS LITTLE AS 2 MI AHEAD OF THEM DURING THE APCH AND HE FELT THAT THIS WAS NORMAL. THE ATP'S TCASII EQUIP WAS INOP ON THIS FLT AND HE HAD TO VISUALLY ESTIMATE HIS DISTANCE BEHIND THE B727. HOWEVER, HE STATED THAT THE B727 WAS JUST TURNING OFF OF THE RWY WHEN THEY HIT THE WAKE OVER THE THRESHOLD.

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.