72 character truncation limit is invalid for fixed-form comments

[airwin1]

As a result of this bug many of the trailing characters in my fixed-form comments have been truncated. I assume below that the fixed-form standard does not limit the lengths of comments in any way (since they are just ignored by compilers), but if there is a limit it must be at least 80 characters long so this is clearly a bug in the current python script regardless of whether the fixed-form limit is 80 or larger.
I worked around this issue by simply commenting out
line = self.truncate_extra_linewidth(line)
but the correct fix to allow unlimited-length fixed form comments would be to locate the start of comments (if any) on each line and only truncate to 72 characters the part of the source line that occurs before that start of comment.