Flying from Madrid to New York we have a 1h 50min. Transfer time. Do you think this is enough time? Flight arriving in Brussels at 08:40 and leaving to JFK at 10:30. Both flights with Brussels Airlines.
If you booked the journey as one ticket you are guaranteed to be transported to your final destination (JFK) regardless of whether you make the connection at BRU or not. Indeed, if you miss the connection the airline will re-route you on a different flight.
Having said this, what happens when you land at BRU and have to transfer? You will arrive at gates A (Schengen to Schengen flights). From there you'll have to go through passport control to exit the Schengen area. This will take some time, especially due to the recent events at BRU. Once you are done with the passport checks, you'll have to transfer to gates T or B depending on where your flight is leaving from. Both transfers are done by walking, and the way is clearly signposted. Gates A and T are close to each other, gates A and B are approximately 1km apart.
I think that 1h50m should be plenty of time to do this. Some claim that the minimum transfer time at BRU is 45-60 minutes. If you get through passport controls swiftly, and don't spend too much time shopping you should make the transfer comfortably.
Keeping in mind things could be slower at Brussels Airport due to recent events, the minimum transfer time is around 50min (according to Brussels Airlines) so if passport control goes quickly you should be fine with the time you have.