Skyhawk 172/Cutlass 172
Air Traffic Control Fully Certified
Situational Awareness; Communication Breakdown
ATC Issue All Types; Conflict NMAC; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Procedure; Human Factors
Helicopter was a couple of miles west of the airport. They requested to cross midfield; at Saticoy St; which is north of the Control Tower; and then continue on to Burbank Tower's airspace. Helicopter was approved to cross as requested; and instructed to contact BUR after crossing. As the Helicopter approached the Tower from the west; they were about to disappear from sight as they passed overhead. There was a C172; departing Runway 16L. I issued traffic to the Helicopter about the departing traffic. Helicopter replied with a roger; and then a second later reported the Cessna in sight. At this point the Helicopter was not at Saticoy St (or on the north side of the Tower). Helicopter had disappeared from sight; and passed directly over and slightly south of the Tower. I observed the Helicopter pass behind and slightly below the flight path of C172. C172 inquired the Local Controller about the Helicopter and was told that the Helicopter had them in sight. Although the designated place for helicopters to cross is at Stagg St (as visually depicted in the local helicopter operations and routes map; between Taxiways Foxtrot and Golf) the text of the same brochure states that; 'helicopters will cross midfield'. The midfield point of the airport is approximately 1;500 FT south of where Stagg St is located; closer to Taxiway Kilo. Helicopter requested to cross midfield at Saticoy; this point is only a couple hundred feet south of Stagg St. It is a safe place for helo's to cross because that is where most arrivals and departures are at their lowest point. However; the point that the Helicopter actually crossed was well south of Saticoy as per their initial request. This put them in a closer proximity to departing aircraft. I recommend that the brochure be changed; so the text matches the visual depiction of helicopter crossing points. In addition to the procedural recommendation; I personally will also be more vigilant at scanning and making sure helicopters are indeed crossing at the designated point. Most of the abovementioned points are in close proximity to the Control Tower and anyone transitioning over these points can disappear from sight momentarily. Knowing this; I made that blanket traffic call advising the Helicopter that there was a Cessna departing.
VNY Controller described an NMAC involving a departing aircraft and a Helicopter transitioning overtop the airport. The Controller suggested changes be made to existing crossing procedures.