ZFW center controller reported receiving a handoff of an aircraft believed to be descending. The pil...

Attributes
ACN	1415974
Time
Date	201701
Local Time Of Day	1801-2400
Place
Locale Reference	ZFW.ARTCC
State Reference	TX
Aircraft 1
Make Model Name	Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Direct
Flight Plan	IFR
Aircraft 2
Make Model Name	Widebody Low Wing 3 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

Narrative:

Shortly prior to incident I split sector 14 off from the combined configuration of sectors 14 and 34. The controller on sector 34 was the relieving controller during the same time the sectors were being decombined. Aircraft X; an overflight; en route to sector 14 level at 32000 feet. Aircraft Y was a flash-through from sector 34 landing den using local ZDV standard operating procedures. Aircraft Y was in communication with sector 34 controller; given a descent clearance for den. I thought he was issued descend and maintain 27000 feet; accepted the handoff and with a descent and flashed the aircraft on to the low arrival sector. Assuming aircraft Y was descending I didn't re-evaluate the traffic. The aircraft conflict alert started flashing without enough to time to achieve required separation. Aircraft Y was already below 33000 feet. Do not issue pilot discretion descents to den arrivals. If in pilots discretion descent annotate in 4th line of the data block. Switch all arrivals to sector 14.

Original NASA ASRS Text

Title: ZFW Center Controller reported receiving a handoff of an aircraft believed to be descending. The pilots had been issued discretion descent which delayed the descent; causing a confliction with opposite direction traffic.

Narrative: Shortly prior to incident I split Sector 14 off from the combined configuration of Sectors 14 and 34. The controller on Sector 34 was the relieving controller during the same time the sectors were being decombined. Aircraft X; an overflight; en route to Sector 14 level at 32000 feet. Aircraft Y was a flash-through from sector 34 landing DEN using local ZDV Standard Operating procedures. Aircraft Y was in communication with Sector 34 controller; given a descent clearance for DEN. I thought he was issued descend and maintain 27000 feet; accepted the handoff and with a descent and flashed the aircraft on to the low arrival sector. Assuming Aircraft Y was descending I didn't re-evaluate the traffic. The aircraft conflict alert started flashing without enough to time to achieve required separation. Aircraft Y was already below 33000 feet. Do not issue pilot discretion descents to DEN arrivals. If in Pilots Discretion descent annotate in 4th line of the data block. Switch all arrivals to Sector 14.

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.

ZFW center controller reported receiving a handoff of an aircraft believed to be descending. The pilots had been issued discretion descent which delayed the descent; causing a confliction with opposite direction traffic.