Date: 201601
Local time of day: 1801-2400
Location: LAX.Tower, CA
Light: Night
Aircraft: Small Transport
Flight plan: IFR
Flight phase: Initial Climb
Airspace: Class B LAX
ATC / advisory: Tower LAX
Second aircraft: Large Transport
Reporter organization: Government
Reporter function: Other / Unknown
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Training / Qualification; Situational Awareness; Confusion; Distraction
Second reporter function: Local
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Automation Air Traffic Control; Person Other Person
Contributing factors: Company Policy; Procedure
Primary problem: Procedure

Narrative: Local Control 2 (LC2); cleared Aircraft X for takeoff and issued a 270 heading; LC2 then cleared Aircraft Y on a FIXIT3 RNAV departure. Aircraft Y is supposed to fly a heading of 251 and with a 270 heading issued to Aircraft X establishes a 15 degree divergence. After replaying the scenario in FALCON; Aircraft Y was showing a HDG of 269 offshore which cannot be explained by the service center who initiated a Risk Analysis Event (RAE). If Aircraft Y was indeed on a 269 HDG that would mean that the Aircraft was not flying the SID as issued and would be a pilot deviation. The winds at the time were 250@7 which indicated the wind to be right down the runway.The two aircraft appear to be flying away from each other and it looks like the Aircraft Y is tracking a 251 course and it says a 269 heading probably because the aircraft is crabbing for wind adjustment possibly for winds aloft and the aircraft nose is possibly facing to a heading of 269. If this indeed is the case you cannot expect the tower controller to know what the aircraft; pilots and winds are doing west of the airport at 2;000 feet; especially when the winds are showing a direct headwind on the ground which is what we used in determine what can happen offshore. In the 7110.65 5-8-3(a) outlines the successive departures but only RNAV departures. There is no reference as a RNAV vs non RNAV aircraft. Since there is no guidance and using the LAX SOP 7110.1F; 7-1-9(a) which outlines issuing a 270 HDG to a prop off the 24 complex; we used the 15 degree rule which was successfully applied.In its email to the Front Line Manager (FLM) regarding the RAE; the service center itself stated that it was not sure about the rules and will be asking whoever they need to ask to get a clarification.There should be some rule that states the separation the FAA wants in relation to RNAV vs non RNAV procedure aircraft.The service center should also do all its research and get clarifications before issuing RAE's that they themselves are unsure of.


Second narrative: I cleared Aircraft X for takeoff and told him to turn to a 270 heading at the shoreline. After appropriate separation I cleared Aircraft Y for takeoff and told him the traffic ahead will diverge westbound at the shoreline. I observed Aircraft X turn to his 270 heading and switched him to departure. I advised Aircraft Y that the traffic was no factor and switched him to departure. He advised me he had Aircraft X in sight however I didn't tell him to 'maintain visual separation' as I felt separation already existed. Aircraft X's heading was 270. Aircraft Y's initial track was 249; then 254 (he was on an RNAV departure; Aircraft X was not). I felt that this gave me adequate separation. I don't know what heading Aircraft Y was on; I only know he was supposed to be tracking the 249 then 254. I do not know what the winds aloft were off the departure end. I do not know what heading Aircraft Y was on; however his actual flight path over the surface of the earth should have been the 249 and 254 tracks. It did not appear to me that Aircraft X was on a heading less than 270 which was his intended direction of flight. In hindsight: I could have waited a few more seconds to clear Aircraft Y for takeoff as there was no inherent reason for him to depart immediately after Aircraft Y. Upon hearing Aircraft Y report Aircraft X in sight I could have advised him to 'maintain visual separation'. I could have put Aircraft Y on a 250 heading which would have taken him off the SID in which I would also have had to stop his climb at 3;000; however I would have ensured the diverging courses immediately after departure.As a procedural change I would like clarification on non-RNAV versus RNAV separation as there has been uncertainty at this facility as to what constitutes departure separation with non-RNAV/RNAV aircraft. Also; we can have our props turn to a 275 or 280 to ensure separation is achieved; as opposed to the 270 heading.


Synopsis: LAX Controllers reported of a loss of separation that they did not know about until well after the fact. Someone from the service center advised the Front Line Manager (FLM) about the loss of separation; and in doing so were not sure about the rules and needed more clarification. The controllers want the procedure fixed so this does not happen again. Controllers thought they were using the 15 degree course separation rule.