Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (mon) 5; Air Traffic Control Time Certified In Pos 1 (yrs) 15
Communication Breakdown; Confusion; Situational Awareness
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway; Ground Incursion Runway
Air Traffic Control Issued New Clearance
Airport; Airspace Structure; Human Factors; Procedure
Aircraft X awaiting takeoff. TRACON calls and changes the heading turn left heading 270 to turn right heading 310; which was relayed to me by the Ground Controller; written on the strip and on my pad. Aircraft Y; an aircraft based at this airport (though quite probably not flown by a pilot from this airport) lands; and begins to turn left onto a taxiway which is NOTAMed closed and has been for a couple of months. I issue a right turn onto the crossing runway into our 'bailout' area; and instead of turning right; as I am instructing; he starts a left turn onto the closed portion of a runway  which  is also NOTAMed closed and has been for a couple of months. I have to insistently; and probably not as politely as I should have; tell him to turn right. All of this because I have traffic bearing down on final; but it is not yet imminent. He exits; finally; and we are good. I get Aircraft X onto the runway; LUAW (Line Up And Wait); and clear him for takeoff. On departure; he makes a hard left turn (60 degrees of bank if not more) right into traffic on the downwind. Since I switched him early because I had no conflicts; I have to get on the line to find out what is going on while also issuing a traffic alert to the C172 who is in the way. He finally turns westbound; and I cannot remember if he got the 310 heading; which would have solved everything. Unfortunately; the CIC (Controller In Charge) was also engaged in the issues with Aircraft Y who could not follow directions.Due to the distraction by Aircraft Y; I should have referred back to the strip before launching Aircraft X. I failed to scan my pad and the strip to ensure I issued the heading. Furthermore; I showed a bad example as I am a FLM (Front Line Manager). It is my job to be better than my controllers; and yet I am human.
MYF Local Controller forgot to issue a revised departure heading to a departing aircraft.