THE RPTR TURNED OFF HIS AUTOPHONES AND LOST CONTACT WITH THE CTLR WHILE ON A CLRNC THROUGH LAX CLASS B AIRSPACE. DURING TROUBLESHOOTING HE LOST HIS HDG CTL.

Narrative

CLRED INTO LAX CLASS B AIRSPACE VIA HOLLYWOOD PARK TRANSITION AFTER MULTIPLE PRIOR ATTEMPTS TO GET CTLR ATTN UNSUCCESSFUL. 8500 FT; HDG 320 DEGS ON VNY 140 DEG RADIAL. SOME TURB DURING MULTIPLE RADIO SWITCHES -- TURNED ADF OFF ON AUDIO PANEL (KMA 24). INADVERTENTLY TURNED OFF AUTOPHONES SWITCH FOR HEADSETS; ADJACENT TO ADF BUTTON. AFTER COM FROM ANOTHER ACFT AND NEAR SIMULTANEOUS CTLR HDOF; UNABLE TO RAISE NEW CTLR FREQ. SWITCHED RADIOS; FINALLY RAISED NEW CTLR; WHO ADVISED HE HAD HEARD MY CHK-IN ATTEMPTS BUT WAS UNABLE TO CALL ME. SUGGESTED RECEIVER PROB. DURING TROUBLESHOOTING AND OTHER DISTRS; DRIFTED L OF COURSE. PROBS: 1) LOSS OF SITUATIONAL AWARENESS; RESULTING IN COURSE DEV. 2) IMPROPER AUDIO PANEL OP LEADING TO PARTIAL LOSS OF COMS. CONTRIBUTORY FACTORS: 1) HIGH WORKLOAD. 2) DISTR. 3) ERGONOMICS OF KMA 24 UNIT (AUDIO PANEL) -- 20 BUTTONS; NO LOCK FOR AUTO; 6-FUNCTION SWITCH -- PLENTY OF OPPORTUNITY FOR ERROR. 4) TURB. WHAT I LEARNED: 1) WHAT I KNEW AND DID NOT DO...FLY THE AIRPLANE FIRST! 2) EXTRA CARE WITH SWITCHING IN HIGH WORKLOAD AREAS AND IN TURB.