IF statement with LEN, LEFT & RIGHT formulas

[airportplanner]

Hello, new to Power Bi, sorry if this is a basic question.

I have a column with 2 types of data (lets call it Flight No Colunn) : BA254/BA879 and BA463/548

I have created a helper column that returns the length of each cell (11 or 9)

I would like to create an if command like this:

IF(LEN[Flight No Column]=11, RIGHT[Flight No Column, 5], CONCATENATE(LEFT([Flight No Column], 2), RIGHT([Flight No Column], 5))

However, this does not work as I am combining numbers with text in the same formula.

Do you have any suggestions?

Thank you very much