Thrust reversers?

[CLECA]

All that matters is..... did they deploy the TR's or not?

Why don't other carriers use em? Is there still a problem with uncommanded deployment?

 

[stall022]

engine FOD damage and some airline have maintance agreements with the manufacture based on how many TR deployments/ reduced thrust takeoffs an aircraft does.

 

[chperplt]

If your question is based on that quote, you missed the point of the quote.

 

[CLECA]

If your question is based on that quote, you missed the point of the quote.

No, it just reminded me that no one else really uses them and couldn't remember why. We use them on every landing and I knew others don't. Someone, I think it was CHQ, that has a few A/C without them even installed.

 

[BlackPilot628]

No, it just reminded me that no one else really uses them and couldn't remember why. We use them on every landing and I knew others don't. Someone, I think it was CHQ, that has a few A/C without them even installed.

We had one at CHQ on the United Express side. That airplane has been added to the Charter department. Trans-states has a crap load of E145 with no TR's. It doesn't really make sense to me either. Last time I sat in the Jumpseat of a TSA plane the capt. was explaining to me that they take a weight penalty on planes without TR's.

 

[Mmmmmm Burritos]

Originally Posted by Mmmmmm Burritos
All that matters is..... did they deploy the TR's or not?

Why don't other carriers use em? Is there still a problem with uncommanded deployment?

Whoosh... there goes a fly ball out to left... waaaaaaaay over his head!

 

[Wasted]

Poor guy.

http://forums.flightinfo.com/showthread.php?t=57205&highlight=thrust+reverse

 

[91100 100 set]

We had one at CHQ on the United Express side. That airplane has been added to the Charter department. Trans-states has a crap load of E145 with no TR's. It doesn't really make sense to me either. Last time I sat in the Jumpseat of a TSA plane the capt. was explaining to me that they take a weight penalty on planes without TR's.

I think here at CHQ we have more than one 145 without reversers. They are the "EP's" that everybody loves to complain about. I don't know the whole story, but I think the company picked them up on the cheap from some European operator. Apparently, over in Europe, an operator is charged landing fees based on the weight of the plane, so they built some 145's without a few extra things like thrust reversers, a galley (lousy for customer service, yes), etc to lighten them up (most of the LR's come in around 27,500 lbs BOW, give or take a few hundred, but the EP's are as much as 1,000 lbs less). And in the circle of life of an airliner, they have found their way to CHQ. And I do seem to recall that they are ghost planes without any specific colors for charters and maintenance spares around the system as needed. How many exactly are in the fleet, I don't know.

I have also heard that maintenance is reporting much better brake life in those airplanes than the LR's (with the TR's). The EP's have the smaller "135 brakes" that tend to get hotter with or without the use of reverse. And I guess carbon steel brakes tend to last longer if they get good and hot during use.

 

[CLECA]

[/i]




Whoosh... there goes a fly ball out to left... waaaaaaaay over his head!

Oh that clears things up. Thanks for shedding some light on the situation. I guesss he has no Fu@king clue either.

 

[michael707767]

Last time I sat in the Jumpseat of a TSA plane the capt. was explaining to me that they take a weight penalty on planes without TR's.

actually, thats BS. Aircraft are certified for take off and landing distances without TRs, so there would be no penalty.

 

[aewanabe]

actually, thats BS. Aircraft are certified for take off and landing distances without TRs, so there would be no penalty.

You'd think so, but part 25 allows for the manufacturer to demonstrate WET Runway accelerate-stop distance using Thrust Reversers if installed. So, here at CHQ, on our 2 airplanes without TRs, we do take a weight penalty (for takeoff only) with a wet runway (note that if the runway is grooved it's not really wet, so in reality we almost never actually have to apply this).

The bigger problem with these 2 pos's is the weight and balance issue. One is a "ghost" plane that circulates the system, the other is dedicated to UA with the new UAX paint scheme. The problem with these planes is twofold; they have the same MZFW as a 140, which means they really can only carry 45 adults or so. In addition, the loss of the galley supplies is more for balance issues (without TRs, the basic moment is extremely biased to the nose). As we acquire more 170s for UA we are reducing our 50-seat flying for them by 2 shells, which is supposed to relegate these 2 pos's to charter only. I can't wait.

As to the op's question, I've had a few big iron drivers ask me why we don't use our TRs. In reality we do, but our SOP is to deploy the buckets in idle reverse only, unless needed. Part of the reason the 2 aircraft without the reversers are getting better brake life is it removes the temptation for new jet drivers to spool the TRs on a 10k runway just because it "sounds cool". (And before anyone flames, when I was new to the airplane I gave into the temptation myself a time or three, maybe )

 

[blzr]

Last time I sat in the Jumpseat of a TSA plane the capt. was explaining to me that they take a weight penalty on planes without TR's.

You think? I bet it adds a lot to your accelerate/stop dist.

 

[91100 100 set]

You think? I bet it adds a lot to your accelerate/stop dist.

With all due respect, I believe that those figures are calculated without the use of reverse. After all, what is one of the biggest reasons you'd need to stop before V1, engine failure right? So you bag an engine and need to stop, well you've only got one reverser now anyway, AND it's probably going to be giving you some assymetrical reverse that could pose a problem if you need alot of it.

But I could be wrong. Comments or additions?

 

[michael707767]

I have never heard of an airplane being certified with TRs. As 91,100 said, if you need to stop during takeoff, its likely to be because of an engine failure. I have never flown an aircraft that was certified with TRs, have asked the question everytime.

 

[Dangerkitty]

With all due respect, I believe that those figures are calculated without the use of reverse. After all, what is one of the biggest reasons you'd need to stop before V1, engine failure right? So you bag an engine and need to stop, well you've only got one reverser now anyway, AND it's probably going to be giving you some assymetrical reverse that could pose a problem if you need alot of it.

But I could be wrong. Comments or additions?

TR's are never never never used in the calculations when it comes to stopping the aircraft.

Think of them as gravy. Nice to have to help get you stopped but not required nor used in the certification numbers.

 

[DoinTime]

The CRJ takes a takeoff penalty for a inoperative TR. Don't know why but thats the way it is.

 

[Axel]

In a ERJ, if you're really serious about having to stop and bury the pedals, by the time the TR's deploy and spool you're down to about 70-80 knots or less anyway. They are of little or no value in normal op's and of marginal value in a panic stop, although in that case every little bit helps.

As some have accurately stated, they are not used for Part 25 certification of the performance #'s, however there is indeed an exception for wet runway performance. If there are no TR's (not sure about deferral of one), there is a weight penalty for wet runways.

Now if we could only find a clear-cut definition of "wet runway" we'd be all set. That is for another thread...

 

[purduedchi]

TR's can be used in the calculations of take-off performance. They are never used for calculations when it comes to landings. I have found this out due to numerous amounts of research at my company. On our 145's with thrust reversers, you may defer 1, and only one thrust reverser at a time. Most who fly the airplane understand Qty inst...2, num req 1. However, we also have a s#%tload of european ones that have no thrust reversers. How is it that we can fly some of the same airplanes with no thrust reverser, but other we must have one operational. I was told that you have to account for the worst case scenario. Basically, the reason you can defer one and only one if it is installed is because if you have an egine failure before V1(accelerate stop), you will have the the operating engine AND it's reverser available too you. They did give us some guidance as far as part 25 certification, but I can't find it right now, if I do, I'll post it for you

 

[millhouse21]

The weight penalty the guy mentioned on the TSA 145s is most likely a CG issue. Most of our non TR birds are former swiss planes with a bunch of HUD equip up front (hud removed but the weight is still there) and less weight from the lack of reversers way aft. Unless we have a seriously load of bags, we often can't get 50 peeps in CG. Of course, sometimes those bags put you over gross weight.

 

[blzr]

With all due respect, I believe that those figures are calculated without the use of reverse. After all, what is one of the biggest reasons you'd need to stop before V1, engine failure right? So you bag an engine and need to stop, well you've only got one reverser now anyway, AND it's probably going to be giving you some assymetrical reverse that could pose a problem if you need alot of it.

But I could be wrong. Comments or additions?

You right, you right, glad you brought that up. They are just an added bonus.

 

[BigShotXJTdrvr]

In my opinion, TRs are a useful EXTRA tool, but sometimes I have to remind FOs that we actually do have brakes, and we are allowed to use them at wheel spinup +3 seconds (FAR, FAR quicker to stop a plane than waiting for the engines to spool). Most FOs at XJET have been conditioned for excessive use/dependence on reversers. It's bad airmanship and I'm getting freakin' tired of having to fix problems that check airmen should be fixing. And no I don't want to be a check airman, not any more than I already am, anyway.

 

[h25b]

In my opinion, TRs are a useful EXTRA tool, but sometimes I have to remind FOs that we actually do have brakes, and we are allowed to use them at wheel spinup +3 seconds (FAR, FAR quicker to stop a plane than waiting for the engines to spool). Most FOs at XJET have been conditioned for excessive use/dependence on reversers. It's bad airmanship and I'm getting freakin' tired of having to fix problems that check airmen should be fixing. And no I don't want to be a check airman, not any more than I already am, anyway.

Brakes are VERY expensive to replace, I have no idea how much runway it takes upon landing for an ERJ, but unless necessary for operational considerations I don't understand what many people's hurry is to clear the runway. Remember, if you're "cleared to land" ATC has given you that pavement until you're done with it. I see just as many people frying the brakes just to satisfy their ego and make some predetermined taxiway...

Consistantly hitting the brakes at wheel spin-up + 3 sec. is very hard on the brakes. I would recommend a light application shortly after spin-up (just to verify that they are available) and then slow via TR's until somewhere after 90 KTS.

THIS IS NOT POOR AIRMANSHIP. Poor airmanship is some numb-nut that jumps all over the brakes right after touchdown throwing all of the passengers forward... I can't tell you how many times I've seen a perfectly smooth landing crapped all over by tossing the pax around by jumping all over the brakes...

 

[FurloughedAgain]

I agree (as usual) with H25B. I generally try and brief the taxiway where I intend to clear the runway -- I think it is a good idea to at least consider the most efficient taxi-route to parking.

However...

That is not license to drop it on the numbers and use max braking to make a turnoff. Energy management is a lost art in aviation. Hold the nose off until it comes down of its own accord. Use reverse thrust as necessary. Reverse becomes less effective as speed decreases, so at an appropriate speed then smoothly apply the brakes. If you miss the taxiway... who cares?

If Delta has to go-around behind you, who cares? Go-arounds pay more than landings. As H25B stated the runway is yours. Don't loiter out there, but don't sacrifice smoothness and efficiency to try and assist ATC.

I always cringed in the DC9 when a pilot would go to full reverse and max braking as soon as the wheels were on the ground. The airplane slowed beautifully holding the nose in the air with just the buckets deployed in idle reverse (do not try in MD80s - might strike a bucket). We've all been riding as a passenger when a beautiful landing is ruined by someone plastering the customer's face into the seat-tray in front of them. Whats the rush?

Be an environmentalist....save a rubber -- er carbon fiber -- tree.

 

[pianoman]

According to our latest revision, XJT recommends deploying the reversers, but only spooling them up if necessary for safety reasons. They want you to use the brakes instead, since heating them up wears the carbon brakes less.

Apparently when they warm up this film forms that reduces wear. I know, sounds weird but that's what Embraer says.

 

[Donsa320]

TR's can be used in the calculations of take-off performance. They are never used for calculations when it comes to landings. I have found this out due to numerous amounts of research at my company. On our 145's with thrust reversers, you may defer 1, and only one thrust reverser at a time. Most who fly the airplane understand Qty inst...2, num req 1. However, we also have a s#%tload of european ones that have no thrust reversers. How is it that we can fly some of the same airplanes with no thrust reverser, but other we must have one operational. I was told that you have to account for the worst case scenario. Basically, the reason you can defer one and only one if it is installed is because if you have an egine failure before V1(accelerate stop), you will have the the operating engine AND it's reverser available too you. They did give us some guidance as far as part 25 certification, but I can't find it right now, if I do, I'll post it for you

Hmmm, how do you arrange things so that the failing engine on Take-off is not the one with the operative reverser?
~DC

 

[aewanabe]

I have never heard of an airplane being certified with TRs. As 91,100 said, if you need to stop during takeoff, its likely to be because of an engine failure. I have never flown an aircraft that was certified with TRs, have asked the question everytime.

Could this be because the aircraft you fly were certified in the early 80s at the latest? I'd need to look it up, but I believe there were some changes to part 25 in the mid-nineties, and this may have been one of them.

I don't have my FAR FC handy, but to paraphrase, under part 25 for wet accelerate-stop distance ONLY, there is a section that says "a manufacturor may make allowance for accelerate-stop distance using means other than wheel brakes, so long as no extraordinary pilot skill is required to use these means" or words to that effect. In the Embraer specifically, the basic accelerate-stop calculations were applied with TRs in idle reverse, again for wet runways only. This does not apply to dry runway takeoffs, landings, or anything else. Thus for a given runway, if accelerate-stop distance is a limiting factor for our performance, we have a small wet-runway only performance hit that is applied to the airplanes with no TRs.

As far as stopping technique generally, again it is a little unique to this airplane. No one advocates stomping the binders at spin-up plus 3 seconds, but both the manufacturor and company want us starting with a gentle application, then increasing as needed, to heat the carbon brakes soon after touchdown. Holding the nose off for long just guarantees it will de-rotate itself with an emphasis after the elevator runs out of authority. As far as the TRs go, deploying them in idle is actually pretty helpful. Not only do you get the bucket drag, but those allisons put out a decent amount of residual thrust at idle. It's just not that useful to spool the suckers most of the time.

 

[FlyChicaga]

According to our latest revision, XJT recommends deploying the reversers, but only spooling them up if necessary for safety reasons. They want you to use the brakes instead, since heating them up wears the carbon brakes less.

Apparently when they warm up this film forms that reduces wear. I know, sounds weird but that's what Embraer says.

I pretty much follow this guidance. Reversers out on every landing, but only spooled on contaminated runways and in very gusty conditions. The brakes do a great job, except in the ERJs where the temps go through the roof. LRJs, XRJs, no problem. The only people that have issues with the brakes are the lead-foots who mash on them like there is only "off" and "on" settings.

 

[stall022]

According to our latest revision, XJT recommends deploying the reversers, but only spooling them up if necessary for safety reasons. They want you to use the brakes instead, since heating them up wears the carbon brakes less.

Apparently when they warm up this film forms that reduces wear. I know, sounds weird but that's what Embraer says.

same deal from the mesa Embraer rep. stomp on the brakes on landing to heat them up then release and apply pressure. a few hundred bucks in brakes is still alot cheaper then a few hundred grand for a new engine after it sucks up a few rocks...

 

[KingAirer]

I dont believe stompin on them right after touch down is the prefered method stall.

 

[LAXSaabdude]

Most FOs at XJET have been conditioned for excessive use/dependence on reversers.

Interesting. Completely the opposite at Eagle. Our ops are fairly strict about when we can use reverse. Runway less than 7000', or wet runway of any length, and then only at idle.

Can't tell you the number of times it's been the FOs leg going into SNA or SBP, or landing on a wet runway, when they never even touch reverse, and go right for the brakes. Had a guy almost slide us off the edge of a wet runway when he got right on the brakes after landing, I had to take it from him.

My policy is to use T/Rs EVERY TIME I am allowed. Much smoother and less jarring then using the brakes, and much safer on a wet runway.

LAXSaabdude.