Small Aircraft; High Wing; 1 Eng; Fixed Gear
Air Traffic Control Fully Certified
Communication Breakdown
ATC Issue All Types; Conflict NMAC
General None Reported / Taken
Procedure; Airport; Human Factors
A high-wing single engine landed on Runway 31L and was told to make a 180 back-taxi Runway31L cleared for takeoff. A small twin a minute later was given a takeoff clearance on Runway 31R. The high-wing single engine started takeoff roll before the small twin. The high-wing single engine rotated just before the small twin; the small twin passed the high-wing single engine when both were less than 10 FT off the ground. The distance between the runways is 300 FT. Do not give a 180 back-taxi and takeoff clearance at the same time. The Local Controller did not think twice about this operation since it is a common practice here.
A high-wing single engine; after landing Runway 31L at RHV; was cleared to back-taxi to the approach end and simultaneously cleared for takeoff (Runway 31L has no accessible parallel taxiway; thus the routine use of back taxi clearances practicing full stop landings). After completing the back taxi the high-wing single engine began its takeoff roll simultaneously with a small twin on Runway 31R. When both were airborne their horizontal separation was only about 300 FT; the centerline spacing between the two runways.