Can I use a 50L pack for carry on?

Flying tomorrow and I was curious if my BD 50l is too big to be considered a carry on? It won't be stuffed full and weight shouldn't be an issue. I really don't want to check it and run the risk of losing it and/or it's contents. Anyone carry on a 50L pack before? I'm flying Jet Blue if that matters.

Never flown jet blue but I've taken some packs pretty close to 50 liters on planes... It'll be tight. If your concerned you could buy a pack to duffle converter and check it. Luggage isn't lost that often... Usually....

Check the airline's website (or call) for dimensional limitations for carry-on. Compare that to your pack. Done.

My standard carry-on is an Arc'teryx RT45. Its a 45L bag. Packed full it fits like a glove in the overhead compartment. It's a roll-top, so there isn't the extra volume of the brain. If you underpack the 50L, stuff the brain inside the bag and compress the contents you should be good to go.

Another logical approach would be to find the maximum allowed carry-on dimensions, go find your tape measurer and do the math...

just strip it down, remove the lid if necessary or pack into the main compartment and compress it to make it small. Should be fine.

I've carried on a stripped down 50L Alpinisto. Fits alright, I crank down the straps and everything but I've carried a full set of gear (rack, rope, harness, helmet, shoes, and chalkbag).

Good enough. Thanks

Slightly off topic...

In January I flew to VA on US Air with one bag. It wasn't a 50L pack but it was about as large. They were charging $25 per bag for checked bags so I carried it on. When I boarded the plane I was told the bag was too large for carry-on so they checked it for free. After landing they got the bags back to us while we were still on the ramp. The people who paid $25 had to wait for their bags at the baggage claim area.

From Jet-Blue:
Your personal item must not exceed 18"L (45.72 cm) x 15"W (38.1 cm) x 8"H (20.32 cm) height in order to fit under the seat in front of you.

To fit in the overhead bin, your item must not exceed:

for our Airbus A320: 26 inches (66 centimeters) length x 18 inches (45.72 centimeters) width x 12 inches (30.48 centimeters) height
for our EMBRAER 190: 24 inches (60.96 centimeters) length x 16 inches (40.64 centimeters) width x 10 inches (25.4 centimeters) height

I've managed a 70L pack as a carry-on with Southwest Airlines with a little use of the compression straps, give it a quick measure and good luck!

I frequently fly with a 50L pack with a removable lid. Don't over stuff it. I remove the lid and put it under the seat in front of me. If you know you are flying smaller regional jets like Bombardiers or Embraers (look on your itinerary), then compress the pack a bit. Some of those overhead bins are pretty small.