Date: 201812
Local time of day: 0001-0600
Location: PHX.Airport, AZ
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Descent
Airspace: Class A ZAB
ATC / advisory: Center ZAB
Second aircraft: HS 125 Series
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Troubleshooting
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Wake Vortex Encounter
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Aircraft; Airspace Structure; Procedure
Primary problem: Ambiguous

Narrative: Aircraft X was descending via the GEELA arrival. There were at FL240 descending. 14 miles behind was Aircraft Y going to SDL. They are filed on the same route. Procedurally we take them north and get them down to 110 or 090. I started them down to FL240 for airspace with the intent of going lower and left once they cleared an over flight. The pilot leveled at FL240 and asked if they were following someone. I told them about the B738 (Aircraft X) 14 miles in front; they said they got some pretty significant wake turbulence. I asked them to describe it in terms of turbulence; they said moderate turbulence (although they hesitated when they responded) and said they had a significant rolling of the aircraft. I vectored them a little left and staggered them above the B738 until I had enough diverging course to get them lower. I asked the Aircraft X pilot if they were heavier than normal; he said no they were actually very light. The FLM (Front Line Manager) told me to ask Aircraft Y if they had any injuries or damage; they said no.I've had this happen a few times; mostly with B738s and 9s; but also with an A321. It seems to be an aircraft relative size thing; where the following aircraft is smaller or much smaller. It doesn't seem to matter whether the B738 is heavy or not; it appears to be a design issue; much like the B757 wake problem was discovered to be.This is unfortunately a known problem; but the issue does not seem to be adequately communicated to the workforce; specifically the enroute workforce. It seems to be significant enough that it causes consternation among crews. I even had a CRJ7 pilot who piped on frequency and mentioned they had experienced the same thing quite often. I think we need to visit the issue of wake turbulence separation; much like RECAT has done in terminal; to address some of the wake issues we are seeing. Compounding this is the increased traffic in the system and the accuracy of RNAV putting aircraft much more directly behind each other.I think the ERC (Event Review Committee) needs to issue a report to look into this wake turbulence issue with the B738/9/MAX and A321; in addition to the obvious problems of heavies (especially A380; B772/3; B748; A124). At a minimum we need information in the system; if only to let controllers know about the issue (I know wake turbulence was touched on recently in recurrent training; but more from the A380 problem). I think someone will get hurt by a wake encounter.




Synopsis: ZAB Center Controller reported that a Hawker pilot encountered wake turbulence while 14 miles behind a B737-800 aircraft.