FLC OF AN ATR42-500 DELAYED TKOF WHEN THEY DISCOVERED THAT THEY HAD NOT STARTED THE L ENG. TWR DIRECTED THEM BACK TO THE TKOF POS WHERE THE OTHER ENG WAS STARTED AND A SUBSEQUENT TKOF WAS MADE WITHOUT INCIDENT. CAPT NEW IN POS; FO RECEIVING IOE.

Narrative

EVENT OCCURRED DURING DEP FROM MEM. CAPT HAD 850 HRS IN TYPE AND 59 HRS IN L SEAT. FO WAS PF AND WAS ON HIS FIRST LINE TRIP AFTER IOE. CREW TOOK RWY FOR DEP WITHOUT HAVING STARTED THE L ENG. SOUND AND YAW MADE THIS IMMEDIATELY EVIDENT AS PWR CAME UP. FO SAID; 'THIS IS WRONG.' SIMULTANEOUSLY; CAPT SAID; 'WAIT' AND BOTH PLTS REDUCED PWR TO IDLE. CAPT TOLD FO TO ADVISE TWR THAT WE WOULD NEED A MOMENT. TWR REPLIED THAT WE COULD REMAIN ON THE RWY AND DO A 180 DEG TURN IF DESIRED. CAPT STARTED L ENG AND PLT'S REVIEWED ALL SYS AND DEPARTED. DURING CRUISE FLT; POSSIBLE PREVENTION MEASURES WERE DISCUSSED. I FEEL THAT THE FOLLOWING FACTORS CAUSED OR CONTRIBUTED TO THE EVENT. AN INEXPERIENCED CAPT WAS BEING CAREFUL TO MONITOR THE ACTIONS OF A NEW FO. IN DOING SO; CAPT FIXATED ON FO'S ACTIONS WITHOUT MONITORING THE EFFECTS OF THOSE ACTIONS. BOTH PLTS FAILED TO PROPERLY MONITOR ALL SYS. PROPER COMMAND TERMS WERE NOT USED. CAPT FAILED TO PROPERLY DIRECT THE TAXI PROCESS. I THINK THAT THE BEST WAY TO PREVENT SUCH AN INCIDENT IS TO ADDRESS THESE FACTORS. ADDITIONALLY; THE COMPANY PLANS TO CHANGE THE BEFORE TKOF CHKLIST.