Date: 201905
Local time of day: 0601-1200
Location: LAX.Tower, CA
Flight conditions: Marginal
Weather elements / visibility: Cloudy
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B LAX
ATC / advisory: TRACON SCT
Second aircraft: B787 Dreamliner Undifferentiated or Other Model
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Situational Awareness
Second reporter function: Captain; Pilot Not Flying
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Aircraft; Airport; Company Policy; Procedure
Primary problem: Company Policy

Narrative: The weather was VFR with bases of clouds at 2;000 feet and simultaneous approaches in progress. With RECAT rules being applied; Aircraft X was on final. The monitor controller called me on Local Assist 2 position to coordinate asking Aircraft X to increase their speed 15 knots. AT that time; Aircraft X was on a 7 mile final outside the Final Approach Fix. This speed request was due to Aircraft Y closing in on Aircraft X. The spacing requirements for a B787 aircraft is 7 miles on approach in front of and behind. As I was giving a position relief briefing; the final Monitor controller called me to have us issue a go around to Aircraft X. My understanding was that putting Aircraft X back into the pattern would make the TRACON's job easier with spacing requirements rather than re-sequencing Aircraft Y the B787. We complied with the instructions and sent Aircraft X around. After coordinating the altitude and heading with the Departure controller; we issued the departure frequency to Aircraft X. We alerted the Supervisor who then called the TRACON Operations Manager to inquire the reason Aircraft X was sent around and not Aircraft Y. I personally like and have seen the benefits of using RECAT to more efficiently depart aircraft and move them through the ATC system. However; the B787 has been flying into and out of this airport for around 1 year and it is still classified as a G aircraft for wake turbulence which means that if that B787 is in trail of a C208; or C172 it requires 7 miles in trail which is absolutely insane and makes no sense! We have the best and brightest minds working behind the scenes to create a seamless and safe ATC operation throughout the NAS and it concerns me that this mileage issue is still in effect. With that said; I don't know what the TRACON's specific traffic scenario was like for them to determine to send Aircraft X around instead of Aircraft Y which was their call. My main concern is that we are putting risk into the ATC system by not aggressively moving to make category determinations for a type of aircraft that has been in the ATC for more than a year. Lets determine that this aircraft is a B category or even an A category so we can continue our safe operation.


Second narrative: Shortly after passing the Final Approach Fix the Tower assigned us 150 knots. We complied until the aircraft reached 1000 feet and then returned to target speed so as to be stabilized and not get too close to the landing aircraft in front of us. Upon reaching 500 feet Tower issued us a go-around to which we complied. After being handed off to TRACON for vectors back for another approach we queried the controller on the reason for the go-around because the aircraft that landed in front of us appeared to be clearing the runway with adequate spacing. TRACON responded that they did not know the reason and gave us a phone number to call when on the ground. We were concerned because of the low altitude of the go-around and the increased risk and exposure it presented to the aircraft and our operation as well as unsettling the Passengers. After reaching the gate; the base Chief Pilot came to the aircraft and informed us that he had already called the Tower and learned that they issued the go-around based on the spacing requirements of the aircraft that was following us; not the aircraft in front of us. We agreed that we would file ASAP reports to highlight information about the spacing requirements of that particular aircraft.


Synopsis: LAX Local controllers and a 737 Captain reported an aircraft was issued a go-around because the aircraft in trail of them was too close.