Date: 201503
Local time of day: 1201-1800
Location: MWH.Tower, WA
Light: Dusk
Aircraft: Military Transport
Operator: Military
Operating under: Part 91
Flight plan: IFR
Mission: Tactical
Flight phase: Climb
Airspace: Class D MWH
ATC / advisory: Tower MWH
Second aircraft: Military
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Developmental
Human factors: Training / Qualification; Situational Awareness; Distraction; Confusion
Second reporter function: Local; Supervisor / CIC
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
Contributing factors: Procedure
Primary problem: Procedure

Narrative: This airport has a complex layout; and that; combined with the fact that the only ILS goes to 32R; means that it is completely necessary to execute Opposite Direction Operations (ODO) very often; usually multiple times a day.  I was undergoing a skills check with my supervisor signed on behind me.Aircraft X; was holding short of runway 14L/32R at taxiway Foxtrot; at about the 5900 foot remaining mark for 32R.  He requested an IFR clearance with radar vectors to the ILS.  I issued a heading of 180 and instructed him to hold short of 14L at F; and advice ready.  Meanwhile; Aircraft Y was executing multiple ILS approaches to 32R.  When Aircraft X advised ready to depart; I coordinated with Approach correctly and got the release.  Aircraft Y was just turning about an 11 mile final; giving me plenty of time for the 3 minute opposite direction wake turbulence; so I cleared Aircraft X for takeoff.  I maintained sight with both aircraft; and was providing visual separation until Aircraft X was past Aircraft Y.Our SOP states that; unless Tower specifically tells Approach otherwise; Tower is authorized to provide visual separation for all departures and departure/arrival situations.  It has not been updated to reflect the new ODO order; which states that visual separation may not be applied with respect to IFR to IFR ODO operations.  I was not aware of this change; nor was the CIC at the time.A heading of 180 is a standard heading for us; due to traffic flow on the west side of the airport; but the runway heading is now 146.7 (it was recently changed from 144.6).  A 180 does not provide 45 degrees divergence; this should have been a 200 heading.  When I came upstairs about an hour later for another training session; I was informed that the two aircraft passed approximately 2.6 miles apart; which constitutes a major loss of separation.Re-write the local SOP to correctly reflect the new ODO procedures.  Consider re-briefing the changes again.  Brief everyone verbally on the recent changes to runway magnetic heading.  Only use 200 or 100 headings when giving radar vectors to departing aircraft.


Second narrative: During a skills check; developmental cleared the Aircraft X for takeoff ODO (Opposite Direction Operations) to the Aircraft Y.  All cutoff points were met; however; Aircraft X should have been given a heading of 190 instead of 180 to allow for more than 45 degree divergence.  It was simply overlooked by all controllers at the time including the stand alone CIC.Allow visual separation to be applied during ODO.


Synopsis: MWH Tower Developmental; while under a skill check; has a loss of separation during an Opposite Direction Operation involving use of visual separation which they thought they could use.