cannot sum time

[EZ]

I do have a long column in which I write down flying hours:
The sum function works for 5 rows maximum. I am not able to sum 400 rows.
Any idea what to do?

 

[Dave F]

SUM works for 400 rows.

=SUM(A1:A400) will not generate errors.

 

[Toppers]

If the SUM appears incorrect, format cell as Custom==>[h]:mm.