How to check invalid date in AE peoplecode

We are on PT 8.51. When the month and year of the date field is entered as "Invalid", i wanted to process them as invalid rows in my application engine program. For eg: Date field: 13/02/2017 (MM/DD/2017) .. this works as expected .. But when I put date field : 02/30/2017 -- The program abends as Invalid date. I'm using IsDate function to valid. In this scenario, it's not validating it. Any ideas would be greatly appreciated. Thanks,