|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||airport : lga.airport|
|Altitude||msl bound lower : 9000|
msl bound upper : 10000
|Operator||common carrier : air carrier|
|Make Model Name||B737-200|
|Flight Phase||descent : approach|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time last 90 days : 200|
flight time total : 18000
flight time type : 350
|Anomaly||altitude deviation : excursion from assigned altitude|
altitude deviation : crossing restriction not met
non adherence : clearance
|Resolutory Action||controller : issued advisory|
|Consequence||faa : reviewed incident with flight crew|
|Problem Areas||ATC Human Performance|
Flight Crew Human Performance
|Primary Problem||ATC Human Performance|
New york approach gave us a nonstandard descent clearance. We were at 11000 ft when the controller said 'cross 25 mi south of lga at 10000 ft, maintain 4000 ft at your discretion.' so both of us thought this meant descend from 11000 ft to 10000 ft by 25 mi south of lga and continue to 4000 ft at our discretion. At about 35 mi south of lga passing 9000 ft, descending to 4000 ft, new york approach said 'stop at 9000 ft, your clearance was not to descend until 25 DME south of lga.' (no conflict with other aircraft.) I told the new york controller 'that isn't how we understood the clearance.' he said no problem. If new york approach controller had only used proper ATC procedures such as, 'descend to cross 25 mi south of lga at or above 10000 ft, maintain 4000 ft at your discretion,' this situation could have been avoided. I guess in the future I will not accept such a vague clearance.
Original NASA ASRS Text
Title: A B737 FLT CREW MISUNDERSTANDS APCH CTLR CLRNC DUE TO NONSTANDARD PHRASEOLOGY.
Narrative: NEW YORK APCH GAVE US A NONSTANDARD DSCNT CLRNC. WE WERE AT 11000 FT WHEN THE CTLR SAID 'CROSS 25 MI S OF LGA AT 10000 FT, MAINTAIN 4000 FT AT YOUR DISCRETION.' SO BOTH OF US THOUGHT THIS MEANT DSND FROM 11000 FT TO 10000 FT BY 25 MI S OF LGA AND CONTINUE TO 4000 FT AT OUR DISCRETION. AT ABOUT 35 MI S OF LGA PASSING 9000 FT, DSNDING TO 4000 FT, NEW YORK APCH SAID 'STOP AT 9000 FT, YOUR CLRNC WAS NOT TO DSND UNTIL 25 DME S OF LGA.' (NO CONFLICT WITH OTHER ACFT.) I TOLD THE NEW YORK CTLR 'THAT ISN'T HOW WE UNDERSTOOD THE CLRNC.' HE SAID NO PROB. IF NEW YORK APCH CTLR HAD ONLY USED PROPER ATC PROCS SUCH AS, 'DSND TO CROSS 25 MI S OF LGA AT OR ABOVE 10000 FT, MAINTAIN 4000 FT AT YOUR DISCRETION,' THIS SIT COULD HAVE BEEN AVOIDED. I GUESS IN THE FUTURE I WILL NOT ACCEPT SUCH A VAGUE CLRNC.
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.