Widebody Transport
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 3
Confusion; Situational Awareness; Distraction; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Procedure; Human Factors
Sector: 24-16Advanced Technologies & Oceanic Procedures (ATOP) combined on midnight configuration.Flight 1 - Aircraft X at FL380Flight 2 - Aircraft Y at FL390XA:35ZAircraft X requests FL390XA:36ZI respond with 'Unable Higher Due Traffic'XA:36ZFlight responded 'Roger'XA:50ZI sent a clearance out to Aircraft X'Maintain FL380; At Time XB:00Z Climb and Maintain FL390; Climb to Reach FL390 by XB:05Z; Report Level FL390'XA:50ZAircraft X Responded 'Wilco'XA:53ZAircraft X Reported level at FL390XA:56ZI asked Aircraft X with a free text message to confirm that they were at FL390 and I stated that I gave them a clearance to maintain FL380 until XB00z due traffic.The traffic was Aircraft Y. Though the aircraft was traffic at the time of the original request at the time Aircraft X climbed the traffic was not a factor though barely.The flight informed me that the plane automatically transferred FL390 to their mode control altitude window. Since they were expecting FL390. The pilot then executed the change and said that it looks like a software issue because the system did not recognize the first part of the clearance to maintain until (time) but instead transferred FL390.I am not sure if this explanation from the pilot was an attempt to cover a mistake or if it really happened but this situation could have been much worse if the two aircraft were 2 or 3 minutes closer together than they were. I; because of experience; added in a buffer to the time of several minutes as is my practice anyway; but if I had not done that this situation might not have been good at all.We should check the software in aircraft X to see if it is compatible with ATOP complex clearances and insure that this does not happen again.
ZNY Controller issues a clearance to be started at a specific time. The receiving aircraft acknowledges the climb clearance. A few minutes later the pilot reports level and newly assigned altitude. The Controller is confused because the aircraft is level at assigned altitude 4 minutes before the aircraft was to begin its climb. Controller had additional traffic he was concerned with and this was the reason for the delay in the climb. Luckily the Controller added a buffer to the time to climb and there was not a loss of separation.