Narrative:

Flight XXXX (ZZZ-bos) descended from cruise altitude to FL270 with ZNY while en route from champ intersection to pvd VOR. After handoff to ZBW, air carrier X was kept at FL270 until passing over an eastbound air carrier Y flight. Passing the eastern tip of long island, air carrier X requested lower altitude in anticipation of a normal clearance to cross pvd at 11000 ft. The ZBW controller gave air carrier X a slight left vector to avoid traffic to the east, then cleared us to FL210 and to proceed direct pvd. He then handed air carrier X off to another ZBW controller. This controller cleared air carrier X direct to inndy intersection (pvd 093 degree radial/15 dm) and gave a clearance to cross inndy at 11000 ft. This was very helpful, as air carrier X was already high if it had been necessary to cross pvd at 11000 ft. Shortly thereafter, the controller said something to the effect of: 'boston is landing runway 4R, we need you to cross pvd at 11000 ft.' at this point air carrier X was about 20 (?) mi sse of pvd heading northeast toward inndy. As the first officer (PF) extended the speed brakes, went to idle power and began a left turn, the captain queried the controller over the clearance since it necessitated a steep descent to pvd. The ZBW controller reaffirmed the clearance. At this time, air carrier X was entering a left 25-30 degree bank from a heading of about 040 degrees to 340 degrees and descending at about 3500 FPM. As air carrier X approached 17000 ft in a rapid descent, the ZBW controller called out VFR traffic ahead at 15500 ft. Near simultaneously, a TCASII empty diamond contact first appeared on the scope at 11-12 O'clock position. This contact then immediately turned into a solid diamond, indicating less than 6 mi lateral distance and within 1200 ft altitude. Because of the left turn toward pvd, was belly up to the traffic, converging (due to turn radius), and approaching its altitude. Rolling out to gain visual contact would have increased the rate of lateral closure. The flight crew then had to make a snap judgement with zero time for discussion: descend through the altitude of the VFR traffic while on a converging course, or leveloff above the VFR traffic. Captain (PNF) elected the latter course of action, took the aircraft and began to aggressively level off. Air carrier X leveled at 15800 ft (300 ft vertical separation on TCASII), then climbed about 500 ft while clearing to the north of the VFR traffic. Based on the TCASII display, it appeared that the minimum separation was about 3 mi. There was no TCASII TA or RA throughout this sequence of events. Air carrier X asked the ZBW controller whether she was aware of the traffic, and a male voice answered stating they had issued a TA. Presumably, this was the one call air carrier X received while descending into the VFR aircraft approximately 2 mi on the nose. Air carrier X advised ZBW that the flight would not cross pvd at 11000 ft and asked the controller to mark the time and save the (radar) tapes. The ZBW controller then handed air carrier X off to bos approach, which vectored us for an ILS runway 4R. Based on other traffic observed after the handoff, it did not appear to the flight crew that the vectoring over pvd was driven by a need to attain spacing with other aircraft inbound to bos ahead of us. A normal approach and landing was subsequently accomplished. Air carrier X flight regularly receives excellent service from ZBW. This incident was an aberration, albeit a potentially dangerous one. Hopefully, it will serve as a lesson learned for the flight crew and controller. However, it is also a warning of a larger problem that must be addressed by FAA and the industry. Outdated ATC egs that continue to allow uncontrolled VFR aircraft to fly at high altitude (eg, above 10000 ft) in increasingly congested airspace are an invitation to disaster.

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Original NASA ASRS Text

Title: ACR FLT APCHING BOS HELD HIGH AT FL270 REQUIRES RAPID DSCNT TO MAKE XING AT 11000 FT. TAKE EVASIVE ACTION TO AVOID VFR TFC AT 15500 FT.

Narrative: FLT XXXX (ZZZ-BOS) DSNDED FROM CRUISE ALT TO FL270 WITH ZNY WHILE ENRTE FROM CHAMP INTXN TO PVD VOR. AFTER HDOF TO ZBW, ACR X WAS KEPT AT FL270 UNTIL PASSING OVER AN EBOUND ACR Y FLT. PASSING THE EASTERN TIP OF LONG ISLAND, ACR X REQUESTED LOWER ALT IN ANTICIPATION OF A NORMAL CLRNC TO CROSS PVD AT 11000 FT. THE ZBW CTLR GAVE ACR X A SLIGHT L VECTOR TO AVOID TFC TO THE E, THEN CLRED US TO FL210 AND TO PROCEED DIRECT PVD. HE THEN HANDED ACR X OFF TO ANOTHER ZBW CTLR. THIS CTLR CLRED ACR X DIRECT TO INNDY INTXN (PVD 093 DEG RADIAL/15 DM) AND GAVE A CLRNC TO CROSS INNDY AT 11000 FT. THIS WAS VERY HELPFUL, AS ACR X WAS ALREADY HIGH IF IT HAD BEEN NECESSARY TO CROSS PVD AT 11000 FT. SHORTLY THEREAFTER, THE CTLR SAID SOMETHING TO THE EFFECT OF: 'BOSTON IS LNDG RWY 4R, WE NEED YOU TO CROSS PVD AT 11000 FT.' AT THIS POINT ACR X WAS ABOUT 20 (?) MI SSE OF PVD HDG NE TOWARD INNDY. AS THE FO (PF) EXTENDED THE SPD BRAKES, WENT TO IDLE PWR AND BEGAN A L TURN, THE CAPT QUERIED THE CTLR OVER THE CLRNC SINCE IT NECESSITATED A STEEP DSCNT TO PVD. THE ZBW CTLR REAFFIRMED THE CLRNC. AT THIS TIME, ACR X WAS ENTERING A L 25-30 DEG BANK FROM A HDG OF ABOUT 040 DEGS TO 340 DEGS AND DSNDING AT ABOUT 3500 FPM. AS ACR X APCHED 17000 FT IN A RAPID DSCNT, THE ZBW CTLR CALLED OUT VFR TFC AHEAD AT 15500 FT. NEAR SIMULTANEOUSLY, A TCASII EMPTY DIAMOND CONTACT FIRST APPEARED ON THE SCOPE AT 11-12 O'CLOCK POS. THIS CONTACT THEN IMMEDIATELY TURNED INTO A SOLID DIAMOND, INDICATING LESS THAN 6 MI LATERAL DISTANCE AND WITHIN 1200 FT ALT. BECAUSE OF THE L TURN TOWARD PVD, WAS BELLY UP TO THE TFC, CONVERGING (DUE TO TURN RADIUS), AND APCHING ITS ALT. ROLLING OUT TO GAIN VISUAL CONTACT WOULD HAVE INCREASED THE RATE OF LATERAL CLOSURE. THE FLT CREW THEN HAD TO MAKE A SNAP JUDGEMENT WITH ZERO TIME FOR DISCUSSION: DSND THROUGH THE ALT OF THE VFR TFC WHILE ON A CONVERGING COURSE, OR LEVELOFF ABOVE THE VFR TFC. CAPT (PNF) ELECTED THE LATTER COURSE OF ACTION, TOOK THE ACFT AND BEGAN TO AGGRESSIVELY LEVEL OFF. ACR X LEVELED AT 15800 FT (300 FT VERT SEPARATION ON TCASII), THEN CLBED ABOUT 500 FT WHILE CLRING TO THE N OF THE VFR TFC. BASED ON THE TCASII DISPLAY, IT APPEARED THAT THE MINIMUM SEPARATION WAS ABOUT 3 MI. THERE WAS NO TCASII TA OR RA THROUGHOUT THIS SEQUENCE OF EVENTS. ACR X ASKED THE ZBW CTLR WHETHER SHE WAS AWARE OF THE TFC, AND A MALE VOICE ANSWERED STATING THEY HAD ISSUED A TA. PRESUMABLY, THIS WAS THE ONE CALL ACR X RECEIVED WHILE DSNDING INTO THE VFR ACFT APPROX 2 MI ON THE NOSE. ACR X ADVISED ZBW THAT THE FLT WOULD NOT CROSS PVD AT 11000 FT AND ASKED THE CTLR TO MARK THE TIME AND SAVE THE (RADAR) TAPES. THE ZBW CTLR THEN HANDED ACR X OFF TO BOS APCH, WHICH VECTORED US FOR AN ILS RWY 4R. BASED ON OTHER TFC OBSERVED AFTER THE HDOF, IT DID NOT APPEAR TO THE FLT CREW THAT THE VECTORING OVER PVD WAS DRIVEN BY A NEED TO ATTAIN SPACING WITH OTHER ACFT INBOUND TO BOS AHEAD OF US. A NORMAL APCH AND LNDG WAS SUBSEQUENTLY ACCOMPLISHED. ACR X FLT REGULARLY RECEIVES EXCELLENT SVC FROM ZBW. THIS INCIDENT WAS AN ABERRATION, ALBEIT A POTENTIALLY DANGEROUS ONE. HOPEFULLY, IT WILL SERVE AS A LESSON LEARNED FOR THE FLT CREW AND CTLR. HOWEVER, IT IS ALSO A WARNING OF A LARGER PROB THAT MUST BE ADDRESSED BY FAA AND THE INDUSTRY. OUTDATED ATC EGS THAT CONTINUE TO ALLOW UNCTLED VFR ACFT TO FLY AT HIGH ALT (EG, ABOVE 10000 FT) IN INCREASINGLY CONGESTED AIRSPACE ARE AN INVITATION TO DISASTER.

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.