...and yet thrust reverse is used extensively in dry conditions (based on watching airliners land all day at EGCC Manchester and other UK airports).

7 minutes ago, Christopher Low said:

...and yet thrust reverse is used extensively in dry conditions (based on watching airliners land all day at EGCC Manchester and other UK airports).

Same goes for KATL, KFLL.KTPA.KMIA all airports I have spent much time at. 

8 minutes ago, Bobsk8 said:

Same goes for KATL, KFLL.KTPA.KMIA all airports I have spent much time at. 

Doesn't negate what was said, that "Thrust reverse has only limited braking effect" in the real world.
On dry runways, it's more to do with improving the stopping margin by removing residual forward thrust.

https://simpleflying.com/airbus-a380-reverse-thrust/

 

I just landed the 737-600, with auto brake off and no manual braking until around 60 knots, stopped in around 3500 feet with full reversers, and manual brakes at 60 knots.   

10 minutes ago, Kyuss said:

I thought I read somewhere that the main benefit from using reverse thrust in dry conditions is mainly to take some of the load off the brakes so they don't get as hot and thus can have a quicker turn around. In fact the reverse thrust won't alter your stopping distance (again, in dry conditions at least) or it's a negligible amount as just reduces heat & wear on the brakes when using autobrakes so you stop in the same distance. Perhaps there's an exception when using max autobraking or heavy manual braking, I don't know. I should test this out in MSFS a bit.

Has anyone else come across this? I don't remember where I read it.

I just landed on another flight and didn't use reverse thrust, and my stopping distance with auto brakes set to 2 which I use all the time was much longer. 

Its no secret that ground frication and runway WX conditions are totally wrong. I think Asobo confirmed it, and it will get some attention at some point...I hope...

Reverse thrust certainly becomes proportionally more effective on a wet or contaminated runway, but think about it: it's not actually becoming more effective, the brakes are just becoming LESS effective.  

If reverse thrust didn't contribute meaningfully to stopping on a dry runway, it wouldn't on a wet runway either.  ;)

The difference of course is that on a dry runway, you've got a huge amount of excess braking effectiveness, so if you don't use reverse you can mostly make up for it by just stomping harder on the brakes.

But, for the sake of saving brakes and keeping temps down, reverse use is a normal procedure on every landing.  

Basically, reverse thrust is like free deceleration (negligible fuel burn). 

20 hours ago, jrw4 said:

Have a look at the figure in the link I posted in response to your earlier post. It seems to show how the reserve levers controls the reverse thrust. To any IRL Boeing pilots: HELP!!!

yep  saw  that  but  i was  only  going  by  watching  the  pilots  were  doing  on  touch down  no  where  in  that  utube  did  the  pilots  move  the  throttles  fwd 🙂  need   a rw 737  pilot  to confirm  if  that  is  the correct  procedure in  the  video  i posted  earlier

1 hour ago, pete_auau said:

yep  saw  that  but  i was  only  going  by  watching  the  pilots  were  doing  on  touch down  no  where  in  that  utube  did  the  pilots  move  the  throttles  fwd 🙂  need   a rw 737  pilot  to confirm  if  that  is  the correct  procedure in  the  video  i posted  earlier

Can you clarify the question?  I watched the video you posted and it's correct, if a bit "mechanical" in the sense that he's just slamming the reverse levers around.  But the reverse levers are actually another set of throttles that only function when the regular throttles are at idle.  The reverse levers have a series of detents: lifting them over the first detent deploys the reverser sleeves at idle thrust, the second detent (what most people use and what it looks like he used in the video) is a moderate amount of reverse, and the reverse levers pulled fully back gives full reverse thrust (but still less then full forward thrust N1.).  But detents notwithstanding, the reverse levers are still throttles, meaning that they are levers that are effective along their entire range and smoothly increase reverse thrust the more you pull them up.  They aren't just a switch with 4 positions; they're throttles.

That's why in the sim, if you don't have extra axes to use for reverse, I think the best way to do it is by binding a switch that turns your throttles into reverse levers.  That way, you aren't just selecting a set amount of reverse thrust but can smoothly use more or less as needed, the way you can in the real aircraft by using the reverse thrust levers.

20 hours ago, Christopher Low said:

...and yet thrust reverse is used extensively in dry conditions (based on watching airliners land all day at EGCC Manchester and other UK airports).

This doesn‘t contradict what I was saying. The reason for using it on dry runways is different, though. It‘s not safety related, but operation-related: Using the Reverse Thrust massively reduces the brake cooling time. So instead of having to wait 50 minutes at the gates you‘ll have to wait only 15 minutes for the brakes to cool down. This in turn guarantees a reasonable turnaround time (most medium-haul airliners have about 25-40 minutes max. Turnaround time scheduled). 

There was a school of operational thinking that thought using reverse thrust saved on tire/brake usage, but it turned out that usage of an engine is more costly than usage of a tire/brake, so that school of thought has disappeared completely, at least from what I‘ve heard.

EDIT: Also to be sure - you were talking about MAX reverse, not idle reverse, yes? Idle reverse is standard for each and everyone, but only for the reason to be able to quickly use MAX reverse if necessary.

Edited February 15, 20233 yr by Fiorentoni

14 hours ago, Stearmandriver said:

Basically, reverse thrust is like free deceleration (negligible fuel burn). 

Spooling up an engine has a lot more cost than fuel burn. It‘s not free at all.

1 hour ago, Stearmandriver said:

But detents notwithstanding, the reverse levers are still throttles, meaning that they are levers that are effective along their entire range and smoothly increase reverse thrust the more you pull them up.

Thank you!

9 hours ago, Fiorentoni said:

Spooling up an engine has a lot more cost than fuel burn. It‘s not free at all.

But still the standard, and not idle reverse either.  Like I said, detent two is the norm, and it's a moderate amount of spool.  I used "free" in the sense that it doesn't "cost" the crew anything; there's no downside.  Remember, our job is to operate the aircraft as safely as possible, with no consideration to economics.  It's the bean counters' jobs to turn that into a profitable business.

I don't know of an airline that discourages reverse use to save money.  I do not think I would fly for, or on, such an airline if one exists.  ;)

Edited February 15, 20233 yr by Stearmandriver

49 minutes ago, Stearmandriver said:

But still the standard, and not idle reverse either.  Like I said, detent two is the norm, and it's a moderate amount of spool.  I used "free" in the sense that it doesn't "cost" the crew anything; there's no downside.  Remember, our job is to operate the aircraft as safely as possible, with no consideration to economics.  It's the bean counters' jobs to turn that into a profitable business.

I don't know of an airline that discourages reverse use to save money.  I do not think I would fly for, or on, such an airline if one exists.  😉

Well I don't know what to tell you, but this might be a european / american thing after all. Also at my home airport EDDF only idle thrust is allowed anyway for noise abatement reasons and it's the same at most big airports in europe. Also full reverse is really loud and scares quite a lot of sensitive passengers, which most airlines don't want, obviously. Of course you can do full reverse if the runway conditions ask for it, but this is the rare exception and def not the rule here on big airports. 
I mean come on, if on a dry runway full reverse (like 200 feet runway saved on a 737) is what you need for safety there's something gone wrong in the landing calculation. You don't go max braking every time either, I suppose, even if that would give you even more safety, and you also don't slam it down with 400 fpm to hit the markers and save some runway. So "as safely as possible" isn't really the whole truth, there's more to that. You do try to have a large and legal safety margin in your calculations and then bring her down smoothly without unnecessary noise and without any unnecessary engine/brake/tire usage. If lack of traffic in the queue allows here at EDDF with its long runways you can even land without any braking (!) at all until the exit and still have 1/3 of the runway left as a safety margin.
I understand detent two does make away with some of these negatives like noise and engine wear and tear, but then again its effect on LDR on a dry runway is even less. Neither fish nor fowl in my book.
Now if you're with Ryanair and it's 25 minute turnarounds and fly a holiday bomber into some obscure spanish airport in the middle of nowwhere with 7000 feet runway, of course you go autobrake 3, flaps 40 and full reverse because otherwise you'd be - best case - standing an hour at the gates waiting for your brakes to cool or - worst case - blow your tires.

That all said, I think we all agree that in case of any doubt safety has priority over everything else.

Edited February 15, 20233 yr by Fiorentoni

18 hours ago, Stearmandriver said:

Can you clarify the question?  I watched the video you posted and it's correct, if a bit "mechanical" in the sense that he's just slamming the reverse levers around

thx  for  you reply  is  that was  responding  to another  user  where  he  had  suggested  you need  to push  the  throttles  fwd t as well  as  lifting  the  thrust  reversers