B737-800
Flight Crew Air Transport Pilot (ATP)
Training / Qualification; Situational Awareness; Workload
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Weather / Turbulence
General None Reported / Taken
Environment - Non Weather Related; Human Factors; Weather
I was notified by the FOQA team of a flap speed exceedance. I was advised by FOQA that; during approach to ORD; flaps were at 15 and a 'momentary' exceedance to 207 KTS occurred. After this 'momentary' exceedance; speed went back below the maximum flaps 15 speed. The event happened at approximately 4;500 FT. and on glide slope as described to me by the person in FOQA. The following is a description of the event to the best of my recollection; but I can only surmise why the speed momentarily exceeded the limit because I did not see any speed exceedance; nor were there any systems indications; such as warning horns or status messages to tell me a limit had been exceeded. We were initially assigned a speed on the arrival into ORD with a subsequent clearance for approach to 22R. It was the First Officer's leg and he was flying the airplane. At between 6;000 and 5;000 FT on descent; we got into moderate turbulence with some indication of wake turbulence. I asked the Approach Controller what we were following and he told us it was an Airbus. We continued in this turbulence as the First Officer subsequently called for flaps in normal increments with the appropriate verbiage calling out the speed first then the flaps setting. I do remember visually and audibly verifying that the speed at the time of each flaps extension was indeed below the maximum speed for that selection. At some point (I do not remember exactly when); I suggested to the First Officer that he turn off the autopilot and fly about one-half dot high on the glide slope to see if the turbulence would decrease. He stated he was about to do that and turned the autopilot off.We continued on the approach and I completed the Before Landing checklist. As we descended closer to the ground the turbulence decreased and the First Officer did an excellent job of landing the aircraft well within parameters. At no time was a stabilized approach jeopardized. The point at which the FOQA personnel told me the event happened indicates to me that the speed excursion happened while we were in this turbulence and I was completing the Before Landing checklist and possibly heads-down looking at the mechanical checklist or some other item in coordination with the checklist and by the time I looked back at the instruments; the momentary exceedance had already come and gone. Had I seen the exceedance; I certainly would have placed a numbered write-up in the logbook to indicate as such. This event certainly wasn't purposeful nor would I take an aircraft or give an aircraft to someone else knowing a limit had been exceeded.A contributing factor in this case is that I am relatively new in the airplane with between 100 and 200 hours and I am still getting used to the flying characteristics of the airplane; especially when it comes to descents and configurations. I will certainly be more vigilant in the future in regards to speed fluctuations with flaps extended and I will also reduce speed further before selecting flaps making the difference between the limit speed and actual speed larger; so there is more tolerance to speed fluctuations. The aircraft systems should also have indicated; either by an aural or status message; that this limit was exceeded. If it had been; the aircraft would not have flown again without obtaining the necessary inspection before its subsequent flight.
[Narrative #2 contained no additional information]
A B737-800 flight crew had a momentary flap overspeed when they encountered wake turbulence in trail of an Airbus on approach to ORD.