Aero1900

Frontier guy here.

We load up our 321s like a no one else. 230 passengers. Takeoff weights in the low to mid 190s

I've never had to leave anyone behind in Denver before. I doubt we will. My heaviest, hottest takeoff did require us to use the long runway, but we were able to carry everyone and everything on a very high density altitude day. I believe we still made it into the low 30s no problem.

Landing these heavy things on a hot, gusty day in Denver uses some serious runway though

rickair7777

The point of the new motors was fuel efficiency, not thrust. But they tweaked them to maintain thrust better at altitude. Kind of like turbo-normalizing. The sooner you get to cruise altitude the sooner you benefit from lower drag.

FastDEW

Good to know. Thanks for the insight. I jump on you a lot - so thanks for the ride too!

Landing hot and hight cannot be any worse than a 739, they are just pigs.....

Gone Flying

I was. but only burning 8000 in a widebody vs 3500 in an rj is still impressive.

Mesabah

RJ's weren't designed for long range cruise, in fact they should be using turboprops, but passengers hate those things.

phoenix 23684

Looking it as an engineer, low should yield slightly lower and here’s my thinking. If you use max reverse on touchdown, low brakes takes 4 seconds to activate vs 2 for med, therefore everything being equal you would be at a very slightly lower speed when they activate.

Most people I fly with do not understand the relationship between rev and auto brakes. Auto brakes use accelerometers to maintain a constant decel rate, therefore adding rev is not stopping you faster but helping you use less brake pressure when used together.

Now let’s use auto brakes with no rev. Since you are slowing the same mass but at different rates, your temps will be pretty close to the same regardless of low or med use. Think of conservation of energy. It took the same brake energy to slow you down, just applied differently. However when I look at the MEL chart for no break temp. Using MED yields a higher Mu and longer sit time and as someone else has said. You have spoilers also assisting in slowing down.

Vegas sucks for F9. We have no fans on a 321 and after landing our gate is downhill. I use low, Max rev until 70 kts and kill #2 as soon as I can to keep the temps low.

flensr

Spirit has the same issue although it seemed like most of the crews going there routinely have it figured out. You can tell if the previous crew is familiar or not from the 200+ deg difference in brake temps, and if they bothered to tell mx to haul over and turn on the brake fans.

Spirit has the upgraded carbon brakes which favor single application use for maximum thermal performance, so the technique that worked best for me at LAS was max reverser and a single application of brakes approaching the desired turnoff, stowing reversers as late as permissable. Going for A6 or even A7 turnoff helps, and even in the 321 I was usually able to make A6 without much more than a brief application of the brakes. The big problems we'd have were with an occasional old/stubborn or young/inexperienced pilot who would only use min reversers "because the passengers don't like it" and then ride the brakes either manually or with autobrakes the entire landing roll, then ride them to the gate. They'd deplane without calling for brake fans because the carbon brake temps don't spike until quite a while after the last brake application so they'd leave thinking everything was ok but the next crew would see truly awful temps as soon as they got there.

rickair7777

Yes, for shorter legs. Pretty much all the 50 seaters should be props. Some of the 70's too.

Replacement jet flying, about 2+ hours, should be jets both for economic and customer satisfaction reasons.

Qotsaautopilot

Just got an email yesterday stating they are going to implement guidance on braking technique. Now LAS may be an exception but it sounds like they are not as concerned with high brake temps and that “saving the brakes” is actually leading to faster wear on the brakes and faster wear on the engines and unnecessary fuel burn from max reverse when it’s not needed for stopping distance

Aero1900

We have a memo at Frontier asking us to try and avoid using max reverse on our NEOs due to fuel nozzle coking. (CFM Leaps)

All of our 320 NEOs have the brake fans installed, which helps a ton. Clearly, our 321 CEOs desperately need the brake fan option