Date: 201509
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Light: Night
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Second aircraft: B737 Next Generation Undifferentiated
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness
Second reporter function: Enroute
Anomaly: Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic
Contributing factors: Human Factors; Procedure; Weather; Airspace Structure
Primary problem: Procedure

Narrative: On a daily occurrence [adjacent ARTCC sector] hands us two or more aircraft that will lose separation within ten to fifteen miles within our airspace. Management is well aware of this and a lot of times when it's brought to their attention they shrug it off and snicker at it. There was a small area of precipitation just west of VOR ZZZ. Aircraft were deviating around it. [Adjacent ARTCC Sector] handed us two aircraft on a collision course at 35;000 feet. The aircraft were to lose separation within 10 miles of our airspace. Both aircraft were deviating for the weather. The 4th line in Aircraft Y's data block read [deviate left; then direct Airport ZZZ] and Aircraft Y's read [deviate left; then direct Airport ZZZ1]. Either aircraft could turn back on course anytime they wanted without notification. Aircraft X could have turned right into Aircraft Y! There was no positive separation insured by [adjacent ARTCC Sector] controller! Noticing this the Radar Assist immediately called [adjacent ARTCC Sector] controller to assign present headings to both aircraft. [Adjacent ARTCC Sector] controller replied that he already shipped the aircraft! This is unbelievable! The transferring controller is to insure that all conflicts are resolved before transferring communication! This was not done! These aircraft could have collided within five miles of the boundary! This is blatant carelessness of the [adjacent ARTCC Sector] controller!In my opinion [the adjacent ARTCC Sector] takes separating aircraft a low priority. They have become lazy and complacent and is getting worse over the years. They are handing us dangerous situations to deal with on a daily basis! Unfortunately; it's going to take a serious accident or a collision of two airliners before this gets resolved!


Second narrative: I was the Radar controller on Sector XX. [Adjacent ARTCC Sector] hands off 2 aircraft both at 35;000 feet and both deviating left for weather. The aircraft were on a merging course heading into my sector airspace. In the 4th line of the data block it showed both aircraft were cleared to deviate left then direct to a fix when done deviating. If either aircraft had gone back on course there would have been a loss of separation on the [ARTCC/ARTCC] boundary. [Adjacent ARTCC Sector] did not ensure separation of the two aircraft. We had to reach out to [the adjacent ARTCC Sector] to get control of the two aircraft which were still in [the adjacent ARTCC Sector's] airspace to fix the situation. Both aircraft were shipped to my sector before the Radar Assist could get a hold of [the adjacent ARTCC Sector] to ensure the separation.


Synopsis: ARTCC Sector handed off two aircraft deviating for weather to adjacent ARTCC Sector. The two aircraft had clearance to return on course at their discretion which would have put them in confliction with each other. The reporter states it is a common occurrence to receive aircraft from this facility which will conflict with each other soon after entering their airspace.