B737-800
Flight Crew Total 25000
Other / Unknown
Conflict Ground Conflict; Critical
Flight Crew Took Evasive Action
Airport; Human Factors; Procedure
Landed at SNA Runway 19R.  Exited Taxiway E.  Just prior to turning on to Taxiway A noticed helicopter approaching  on Taxiway A flying southbound; opposite taxi flow; at a high rate of speed.  Locked brakes and stopped short of Taxiway A to avoid a collision. Ground Control was busy with radio communications. The helicopter took no evasive action and passed 30 feet off our nose 10-15 feet above the taxiway.  After the helicopter passed us; Ground Control told us to stop short of Taxiway A.  Had we not stopped; the helicopter would have collided with our aircraft. After talking to the Tower Supervisor; my understanding is that Ground Control; with Tower concurrence; can clear helicopters to takeoff from Taxiway A opposite the taxi flow of jets exiting Runway 19R.  I think this is an extremely dangerous practice and collision potential is high.  Runway 19L was available to the helicopter for back taxi and takeoff but was not used.
B737 Captain exiting Runway 19R on Echo reports a near collision with a helicopter air taxiing southbound on Alpha at SNA.