Narrative:

Upon checking in with bradley approach we were initially told to expect runway 33 ILS. I requested runway 24 and we were granted that request. The controller gave us an eastbound vector and descended us to 5000'. (May have been 6000' can't recall.) we were being vectored in from the northwest on a right base to join the ILS to 24. At approximately 15-20 miles northwest of runway 24 while level at our assigned altitude; I began to hear a roaring noise. My initial thought was that there was another aircraft in our near vicinity. I scanned the TCAS readout and saw no traffic advisories. I scoped down to a smaller range and still saw nothing. I scanned outside but did not see any traffic. We were in and out of the clouds (broken clouds; 2000-3000 foot thick) and while visibility was good between the clouds; I was unable to pick up the traffic visually. The captain and I commented something to the effect that there is another airplane and he's got to be right on top of us. Just then I noticed the first illumination of a TA on our TCAS. It was a white +003 directly on top of the aircraft symbol. The TCAS never gave us any ras. I queried the approach controller saying; 'do you have traffic on top of us?' the controller did not seem very concerned and said that there were a pair of F-15s departing barnes (which I believe we were directly south of at the time). He also said that we were in a heavy military operations area and left it at that. He did not offer any more information about the separation we had with the departing fighters. The roar of the passing F-15s lasted somewhere between five and seven seconds.the remainder of the flight was uneventful. My concern is that we were not given adequate separation from the departing F-15s. I suppose that it is possible to hear passing aircraft while in flight and still have adequate separation; but I highly doubt that is the case here. The sound from the fighters was at least as loud if not louder than when you are holding short of 12R in stl and an F-15 is launching right in front of you. And the noise lasted for a sustained seven seconds or so. I am curious to know what kind of separation we were given. I feel that it is highly likely that an ATC error or F-15 pilot error may have reduced our separation. Because of the IMC conditions and insufficient TCAS advisories; I believe that we were completely at the mercy of ATC in this situation. I do not think there is anything we could have done to increase the separation between us and the departing F-15s. I think that ATC could have issued traffic advisories and may have needed to provide greater separation.

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Original NASA ASRS Text

Title: Air Carrier Flight crew reported a NMAC with an F15 near BDL while IMC. Only A TCAS TA was indicated and ATC did not issue a traffic advisory.

Narrative: Upon checking in with Bradley Approach we were initially told to expect Runway 33 ILS. I requested Runway 24 and we were granted that request. The Controller gave us an eastbound vector and descended us to 5000'. (May have been 6000' can't recall.) We were being vectored in from the northwest on a right base to join the ILS to 24. At approximately 15-20 miles northwest of Runway 24 while level at our assigned altitude; I began to hear a roaring noise. My initial thought was that there was another aircraft in our near vicinity. I scanned the TCAS readout and saw no Traffic Advisories. I scoped down to a smaller range and still saw nothing. I scanned outside but did not see any traffic. We were in and out of the clouds (broken clouds; 2000-3000 foot thick) and while visibility was good between the clouds; I was unable to pick up the traffic visually. The Captain and I commented something to the effect that there is another airplane and he's got to be right on top of us. Just then I noticed the first illumination of a TA on our TCAS. It was a white +003 directly on top of the aircraft symbol. The TCAS never gave us any RAs. I queried the Approach Controller saying; 'Do you have traffic on top of us?' The Controller did not seem very concerned and said that there were a pair of F-15s departing Barnes (which I believe we were directly south of at the time). He also said that we were in a heavy military operations area and left it at that. He did not offer any more information about the separation we had with the departing fighters. The roar of the passing F-15s lasted somewhere between five and seven seconds.The remainder of the flight was uneventful. My concern is that we were not given adequate separation from the departing F-15s. I suppose that it is possible to hear passing aircraft while in flight and still have adequate separation; but I highly doubt that is the case here. The sound from the fighters was at least as loud if not louder than when you are holding short of 12R in STL and an F-15 is launching right in front of you. And the noise lasted for a sustained seven seconds or so. I am curious to know what kind of separation we were given. I feel that it is highly likely that an ATC error or F-15 Pilot error may have reduced our separation. Because of the IMC conditions and insufficient TCAS Advisories; I believe that we were completely at the mercy of ATC in this situation. I do not think there is anything we could have done to increase the separation between us and the departing F-15s. I think that ATC could have issued Traffic Advisories and may have needed to provide greater separation.

Data retrieved from NASA's ASRS site as of April 2012 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.