ZNY center controller reported a loss of separation due to an aircraft not climbing as instructed.

Attributes
ACN	1459011
Time
Date	201706
Local Time Of Day	1801-2400
Place
Locale Reference	ZNY.ARTCC
State Reference	NY
Environment
Light	Daylight
Aircraft 1
Make Model Name	Widebody Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 129
Flight Phase	Climb
Route In Use	Oceanic
Flight Plan	IFR
Aircraft 2
Make Model Name	Widebody Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 129
Flight Phase	Cruise
Route In Use	Oceanic
Flight Plan	IFR
Person 1
Function	Enroute Oceanic
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 2.5
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

Narrative:

I took over the sector around time xb:19. At xa:48 aircraft Y issued a climb to reach FL360 by xb:20 and to report level due to traffic. Xa:49 aircraft Y wilco. Xa:58 aircraft X issued at time xb:20 climb to FL350 to reach FL350 by xb:30. Xa:59 aircraft X wilco. Xb:21 I get a sector message restriction has not been met by xb:20 by aircraft Y. Time xb:22 I observe aircraft X at FL344 and aircraft Y at FL350 and demand the aircraft. Then send a message to aircraft Y to confirm altitude. Confirm level FL360. Right after that message went out the aircraft X sent a message that there is traffic at FL350 at time xb:23. Aircraft X received a TCAS advisory and stated traffic passed 2 NM southeast of us. At time xb:24 aircraft Y is now level at FL360. When I reached out to aircraft Y to ask why he was not level he stated they were late in timing due to error they will file a report.atop (advanced technology and oceanic procedures) should not allow these clearances in head on situations. I felt as if I had zero time to fix the situation. These clearances get blown every once in a while and it is only a matter of time before something bad happens.

Original NASA ASRS Text

Title: ZNY Center Controller reported a loss of separation due to an aircraft not climbing as instructed.

Narrative: I took over the sector around time XB:19. At XA:48 Aircraft Y issued a climb to reach FL360 by XB:20 and to report level due to traffic. XA:49 Aircraft Y wilco. XA:58 Aircraft X issued at time XB:20 climb to FL350 to reach FL350 by XB:30. XA:59 Aircraft X wilco. XB:21 I get a sector message restriction has not been met by XB:20 by Aircraft Y. Time XB:22 I observe Aircraft X at FL344 and Aircraft Y at FL350 and demand the aircraft. Then send a message to Aircraft Y to confirm altitude. Confirm level FL360. Right after that message went out the Aircraft X sent a message that there is traffic at FL350 at time XB:23. Aircraft X received a TCAS advisory and stated traffic passed 2 NM southeast of us. At time XB:24 Aircraft Y is now level at FL360. When I reached out to Aircraft Y to ask why he was not level he stated they were late in timing due to error they will file a report.ATOP (Advanced Technology and Oceanic Procedures) should not allow these clearances in head on situations. I felt as if I had zero time to fix the situation. These clearances get blown every once in a while and it is only a matter of time before something bad happens.

Data retrieved from NASA's ASRS site 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.