Narrative:

ZNY cleared flight to descent from FL250 to 17000', direct etx. At approximately FL195 the controller requested an expedited descent to 17000', which was accomplished. As flight began to level at 17000', the controller cleared the flight to descend to 15000'. Apparently he was not satisfied with the rate of descent out of 17000', and assigned an immediate course reversal, which was complied with. At 15500', the controller reclred the flight direct direct to etx and called traffic at 16000', 5 mi, as the flight leveled at 15000'. Flight reported the traffic in sight. The controller was obviously frustrated with the situation, and prior to handoff to abe approach, made a remark similar to 'your life depends on following my instructions.' as always in this sector, traffic was very busy on the frequency. 2 questions arise from this incident. First, what constitutes an 'expedited descent?' obviously, there was a misunderstanding between flight crew and controller about the rate of descent out of 17000'. However, at some point approaching the level off altitude, the rate of descent must be shallowed to achieve a level off that is reasonable for the passenger. Further, the level off at 17000' further slowed the rate of descent. Secondly, was it necessary to take the flight down to 15000 from 17000' if such a conflict was imminent? In summary, there was an obvious misunderstanding between controller and flight crew in this situation. The flight crew was not trying to make the controller's job any more difficult. And while an abrupt maneuver is, of course, more desirable than a midair collision, it was unfortunate that the situation developed to that point. Traffic on the frequency precluded any further discussion of the problem with the controller.

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Original NASA ASRS Text

Title: ACR MLG SLOW DESCENT RATE BLAMED BY ATC FOR NEAR LOSS OF SEPARATION.

Narrative: ZNY CLRED FLT TO DSNT FROM FL250 TO 17000', DIRECT ETX. AT APPROX FL195 THE CTLR REQUESTED AN EXPEDITED DSNT TO 17000', WHICH WAS ACCOMPLISHED. AS FLT BEGAN TO LEVEL AT 17000', THE CTLR CLRED THE FLT TO DSND TO 15000'. APPARENTLY HE WAS NOT SATISFIED WITH THE RATE OF DSNT OUT OF 17000', AND ASSIGNED AN IMMEDIATE COURSE REVERSAL, WHICH WAS COMPLIED WITH. AT 15500', THE CTLR RECLRED THE FLT DIRECT DIRECT TO ETX AND CALLED TFC AT 16000', 5 MI, AS THE FLT LEVELED AT 15000'. FLT RPTED THE TFC IN SIGHT. THE CTLR WAS OBVIOUSLY FRUSTRATED WITH THE SITUATION, AND PRIOR TO HDOF TO ABE APCH, MADE A REMARK SIMILAR TO 'YOUR LIFE DEPENDS ON FOLLOWING MY INSTRUCTIONS.' AS ALWAYS IN THIS SECTOR, TFC WAS VERY BUSY ON THE FREQ. 2 QUESTIONS ARISE FROM THIS INCIDENT. FIRST, WHAT CONSTITUTES AN 'EXPEDITED DSNT?' OBVIOUSLY, THERE WAS A MISUNDERSTANDING BTWN FLT CREW AND CTLR ABOUT THE RATE OF DSNT OUT OF 17000'. HOWEVER, AT SOME POINT APCHING THE LEVEL OFF ALT, THE RATE OF DSNT MUST BE SHALLOWED TO ACHIEVE A LEVEL OFF THAT IS REASONABLE FOR THE PAX. FURTHER, THE LEVEL OFF AT 17000' FURTHER SLOWED THE RATE OF DSNT. SECONDLY, WAS IT NECESSARY TO TAKE THE FLT DOWN TO 15000 FROM 17000' IF SUCH A CONFLICT WAS IMMINENT? IN SUMMARY, THERE WAS AN OBVIOUS MISUNDERSTANDING BTWN CTLR AND FLT CREW IN THIS SITUATION. THE FLT CREW WAS NOT TRYING TO MAKE THE CTLR'S JOB ANY MORE DIFFICULT. AND WHILE AN ABRUPT MANEUVER IS, OF COURSE, MORE DESIRABLE THAN A MIDAIR COLLISION, IT WAS UNFORTUNATE THAT THE SITUATION DEVELOPED TO THAT POINT. TFC ON THE FREQ PRECLUDED ANY FURTHER DISCUSSION OF THE PROB WITH THE CTLR.

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.