Two new york center oceanic controllers reported of an altitude clearance that caused confusion for ...

Attributes
ACN	1386341
Time
Date	201609
Local Time Of Day	0601-1200
Place
Locale Reference	ZNY.ARTCC
State Reference	NY
Aircraft 1
Make Model Name	Widebody Transport
Operating Under FAR Part	Part 129
Flight Phase	Climb
Route In Use	Oceanic
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute Oceanic
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 3
Person 2
Function	Oceanic Enroute
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 4
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter Weather / Turbulence

Narrative:

I was working the north atlantic sector; as I was coordinating aircraft to gander; approaching gander's boundary there were a lot of deviations and a SIGMET was put up; gander advised aircraft X had only two options on his route FL390 or FL290; aircraft X chose FL390. I had to step climb him reference all the other traffic crossing to santa maria; I gave him a climb to be level FL380 by [ten minutes] and then a time to be level FL390 by [40 minutes]. Due to many deviations I couldn't keep this altitude restriction and get aircraft around weather I told aircraft X to amend clearance and maintain FL360; (as it was the only clean altitude) and he wilco'd the clearance. After I was relieved by another controller; he got a report of aircraft X climbing to FL370 and it was the same altitude as the aircraft deviating into him; the conflict probe went off and loss of separation occurred. I only can concur to knowing I gave him an amended clearance to only maintain FL360 and not to climb.I think sectors should be split out more later at night especially when there is weather over the ocean and deviations are occurring right before boundary.

Original NASA ASRS Text

Title: Two New York Center Oceanic Controllers reported of an altitude clearance that caused confusion for the pilot and a loss of separation between two aircraft.

Narrative: I was working the North Atlantic Sector; as I was coordinating aircraft to Gander; approaching Gander's boundary there were a lot of deviations and a SIGMET was put up; Gander advised aircraft X had only two options on his route FL390 or FL290; aircraft X chose FL390. I had to step climb him reference all the other traffic crossing to Santa Maria; I gave him a climb to be level FL380 by [ten minutes] and then a time to be level FL390 by [40 minutes]. Due to many deviations I couldn't keep this altitude restriction and get aircraft around weather I told aircraft X to amend clearance and maintain FL360; (as it was the only clean altitude) and he wilco'd the clearance. After I was relieved by another controller; he got a report of aircraft X climbing to FL370 and it was the same altitude as the aircraft deviating into him; the conflict probe went off and loss of separation occurred. I only can concur to knowing I gave him an amended clearance to only maintain FL360 and not to climb.I think sectors should be split out more later at night especially when there is weather over the ocean and deviations are occurring right before boundary.

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.

Two new york center oceanic controllers reported of an altitude clearance that caused confusion for the pilot and a loss of separation between two aircraft.