ZOB controller described a conflict event when an issued crossing restriction was missed; the report...

Narrative:

A B757 was level at FL390 northbound on route. In compliance with SOP; I gave/received lower on the aircraft from lorain sector and told them to cross 85 miles south of yxu at FL330. The aircraft read back this clearance and it was correct. The sector to the north of me called to point out another air carrier; a westbound flight that was at FL360. While he did this; I showed him the B757; told him they would be descending and I would miss the other flight. One minute out from 85 south of yxu I asked the B757; who was still at FL390; if he would make his restriction and they said yes. I asked him to verify that they would cross 85 south and they replied they would; however they were already at that point and in conflict with the other aircraft. I called traffic asked them to report out of FL350 and no loss of separation resulted. Where I show 85 south of yxu is not where they crossed. This is not the first time. Numerous aircraft over the last several years have missed the restrictions off of yxu. This leads me to believe that either our map miss represents where yxu is from our boundary or there is a problem with DME off of yxu.

Original NASA ASRS Text

Title: ZOB Controller described a conflict event when an issued crossing restriction was missed; the reporter noting this NAVAID DME dependant restriction is often missed; questioning the DME and/or RADAR display accuracy.

Narrative: A B757 was level at FL390 northbound on route. In compliance with SOP; I gave/received lower on the aircraft from Lorain Sector and told them to cross 85 miles south of YXU at FL330. The aircraft read back this clearance and it was correct. The sector to the north of me called to point out another Air Carrier; a westbound flight that was at FL360. While he did this; I showed him the B757; told him they would be descending and I would miss the other flight. One minute out from 85 south of YXU I asked the B757; who was still at FL390; if he would make his restriction and they said yes. I asked him to verify that they would cross 85 south and they replied they would; however they were already at that point and in conflict with the other aircraft. I called traffic asked them to report out of FL350 and no loss of separation resulted. Where I show 85 south of YXU is not where they crossed. This is not the first time. Numerous aircraft over the last several years have missed the restrictions off of YXU. This leads me to believe that either our map miss represents where YXU is from our boundary or there is a problem with DME off of YXU.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	993909
Time
Date	201202
Local Time Of Day	1801-2400
Place
Locale Reference	ZOB.ARTCC
State Reference	OH
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Descent
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Supervisor / CIC
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Airspace Violation All Types

ZOB controller described a conflict event when an issued crossing restriction was missed; the reporter noting this NAVAID DME dependant restriction is often missed; questioning the DME and/or radar display accuracy.