thanks everybody .
i know the question is kinda weird .seems has nothing to do with our flight .
but the other day i saw this procedure on a website about 737 operation ,during the engine shut down ,it says :turn off the beacon when the N2 drops below 20.and i do not know where is this from and if any airline follow this rule.cuz my company doesn't .and there is this another picture .when we arrive at the gate .the captain cut off the engines and the first officer turn off the beacon which give the ground mechanic the signal the engines are shut down now and he can come over to put the chocks in .
so bring this two piecese info together comes this question .
any 737NG pilots here with cmf56-7 engine ?plz tell me what u do during the shutdown flow .