Narrative:

On flight air carrier xx, pit-phl at FL250, I received clearance to cross 10 mi east of lrp at 11000'. 19 mi west of lrp at 17000', I was told to level at 16000' and turn left for traffic. After questioning ATC about my clearance, he thought we were cleared to cross lrp at 11000'. We continued to receive vectors and landed at phl. While we never violated either of the above clrncs, we could not have made a 10-mi west of lrp at 11000', and that may have been the original intention of ATC. Clrncs to cross east or west are easily misunderstood. Instead the term 'before reaching' or 'after passing' are more descriptive and less prone to misinterp.

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Original NASA ASRS Text

Title: ALT DEVIATION. UNDERSHOOT ON DESCENT. CROSSING RESTRICTION NOT MET.

Narrative: ON FLT ACR XX, PIT-PHL AT FL250, I RECEIVED CLRNC TO CROSS 10 MI E OF LRP AT 11000'. 19 MI W OF LRP AT 17000', I WAS TOLD TO LEVEL AT 16000' AND TURN LEFT FOR TFC. AFTER QUESTIONING ATC ABOUT MY CLRNC, HE THOUGHT WE WERE CLRED TO CROSS LRP AT 11000'. WE CONTINUED TO RECEIVE VECTORS AND LANDED AT PHL. WHILE WE NEVER VIOLATED EITHER OF THE ABOVE CLRNCS, WE COULD NOT HAVE MADE A 10-MI W OF LRP AT 11000', AND THAT MAY HAVE BEEN THE ORIGINAL INTENTION OF ATC. CLRNCS TO CROSS E OR W ARE EASILY MISUNDERSTOOD. INSTEAD THE TERM 'BEFORE REACHING' OR 'AFTER PASSING' ARE MORE DESCRIPTIVE AND LESS PRONE TO MISINTERP.

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.