How to convert JSON data inside a pandas column into new columns

If you already have your data in acList column in a pandas DataFrame, simply do:

import pandas as pd
pd.io.json.json_normalize(df.acList[0])

Alt AltT    Bad CMsgs   CNum    Call    CallSus Cou EngMount    EngType ... Sqk TSecs   TT  Tisb    TrkH    Trt Type    VsiT    WTC Year
0   NaN 0   False   1   7503    NaN False   United States   1   3   ...     3   a   False   False   1   CRJ2    0   2   2001
1   8025.0  0   False   35445   NaN TEST1234    False   United States   0   0   ... 0262    75229   a   False   False   1   NaN 0   0   NaN

Since pandas 1.0 the imports should be:

import pandas as pd
pd.json_normalize(df.acList[0])