F2TH FLT CREW TAKES OFF WITH L PITOT COVER INSTALLED. MULTIPLE RESULTING ANOMALIES RESULT IN RETURN TO DEP ARPT.

Narrative

AFTER TKOF FROM RWY 1; MULTIPLE IRREGULARITIES SHOWED UP AND CONTINUED TO SHOW UP AS WE DEPARTED THE AREA AND WERE CLBING TO ALT. I HAD NO AIRSPD INDICATIONS ON THE PLT'S SIDE EXCEPT IN REVERSION; ADC #1 SEEMED TO HAVE FAILED. THE YAW DAMPER LIGHT CONTINUED TO COME ON AFTER RESET; AILERON FEEL ANNUNCIATOR LIGHT WAS ON STEADY; AILERON ZERO ANNUNCIATOR LIGHT WAS CYCLING ON AND OFF. AFTER TRYING TO ASSESS OUR PROB AND THINKING WE HAD TAKEN IN WATER IN A CRITICAL AREA; DURING THE PROCESS OF THAWING OUT THE ACFT FROM A PREVIOUS DAY'S 3 INCH SNOW FALL; I ELECTED TO RETURN TO ZZZ. ATC ADVISED THAT DUE TO THE PROBS WE WERE ENCOUNTERING AND THE HVY TFC AREA; THEY WERE GOING TO ISSUE AN EMER FOR US TO EXPEDITE OUR ARR BACK TO ZZZ; WE RETURNED AND LANDED NORMALLY. POSTFLT FOUND OUR PLT SIDE PITOT TUBE STILL HAD THE PITOT COVER INSTALLED. ACFT WAS RE-DISPATCHED AND CONTINUED TO EST. AS EMBARRASSING AS THIS IS AND IT IS NO EXCUSE AND NONE IS INTENDED; OUR PITOT COVERS WERE MISSING THE RED REMOVE BEFORE FLT FLAGS AND CONSEQUENTLY THESE COVERS; MADE OF METAL; JUST SLIGHTLY LARGER THAN THE PITOT TUBE ITSELF AND AS WE NOW KNOW; ARE EASILY OVERLOOKED.