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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.
| Attributes | |
| ACN | 1297363 |
| Time | |
| Date | 201509 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | ZNY.ARTCC |
| State Reference | NY |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | Widebody Transport |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise Climb |
| Route In Use | Oceanic |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Widebody Transport |
| Operating Under FAR Part | Part 129 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | Enroute |
| Qualification | Air Traffic Control Fully Certified |
| Experience | Air Traffic Control Time Certified In Pos 1 (yrs) 3 |
| Events | |
| Anomaly | ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy |
Narrative:
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.
Original NASA ASRS Text
Title: 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.
Narrative: 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.
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.