2. Add a comma behind the line END_DATE as [Aircraft End Date] and press Return to create a new line.
3. On the new line, put the following expression: If(Year(BEGIN_DATE) < 1990, 'Classic', 'Current') as [Aircraft Age Classification]
4. As the 2010 update only contains aircraft that are newer than 2010, we do not need to use the conditional expression, instead we can use a fixed value.
5. Add a comma behind the line END_DATE as [Aircraft End Date] and press Return to create a new line.
6. Put the following expression on this line: 'Current' as [Aircraft Age Classification]
7. Save and reload the document.
8. Add Aircraft Age Classification field to the Aircraft multibox.
Remove steps 5 and 6. Step 6 will create a conflict of names.
