Boeing 747 Super Max 8 first flight was on 1/29/2016

Lion Air flight 610....33 months from 747-max-8 first test flight 
From and including: Friday, January 29, 2016
To, but not including Monday, October 29, 2018

33 months excluding the end date

Lion Air Flight 610

https://en.wikipedia.org/wiki/Lion_Air_Flight_610#Flight_details_and_accident


Boeing 747 Super Max 8 first flight was on 1/29/2016 
From and including: Friday, January 29, 2016
To, but not including Sunday, March 10, 2019
3 years, 1 month, 10 days excluding the end date. = 311


That's 3/11 and it crashed at 1:38 am est that's 3/11 our time

Ethiopian Airlines Flight 302

https://en.wikipedia.org/wiki/Ethiopian_Airlines_Flight_302