ANITIX87
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Thrust Reverse Deployment

Sun Aug 07, 2005 2:50 am

I had two flights August 4th (two days ago). I flew ZRH-LHR on an LX A320, and LHR-EWR on a VS 744. Thrust reverse was not used on either flight. I am not full of hot air, I was in view of the engines and watched. There was no roar typical of the reversers, and I did not see the cowling slide back on the 744 or open up on the A321. Just wondering if this is normal, and I was also surprised because it seemed to me like the A321 came in insanely fast into LHR. Any insight?!

TIS
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Matt72033
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 3:04 am

long runways at LHR small A321, was it a dry day? they may just have not needed it, or they could have been locked out due to one side bein U/S?

those are my ideas, maybe someone else can shed more light!
 
ANITIX87
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 3:13 am

It was a beautiful day, perfect conditions, except for a little wind. What does U/S mean? If it means one side wasn't working, wouldn't the only way to know be by finding out the hard way? Meaning, the aircraft would probably have had a bad landing experience and would not be in use. I thought of that, but it doesn't seem plausible that the pilot could possibly know if one side wasn't working. Thanks for your ideas.

Now, the hard one. Why wouldn't a fully-loaded 744 use it landing in EWR after only 7 hours in the air?
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DColeMAN
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 3:28 am

Reverse thrust isn't always required (especially on long runways) and instead just the spoilers and brakes are deployed/required. Sounds as though this happened on both of your landings.

Dale
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Finkenwerder
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 3:59 am

U/S = Unserviceable and I don't think TR inop is on the MEL ?
 
tinpusher007
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 4:29 am

Quoting ANITIX87 (Reply 2):
I thought of that, but it doesn't seem plausible that the pilot could possibly know if one side wasn't working.



Quoting Finkenwerder (Reply 4):
U/S = Unserviceable and I don't think TR inop is on the MEL ?

It is entirely plausible that the pilot would know if the T/R's were not working. In fact it is the pilot's job to know...they review the mx logs everytime they get on a new plane for that very purpose.

And yes T/R's can be on the MEL which is a list of equipment that can be inop without precluding the aircraft from being dispatched. Aircraft can definately be dispatched with inop thrust reversers. As for the VS 744, maybe they had a good headwind and thus a slower groundspeed. LHR-EWR is not even close to a 744's design range and therefore a relatively light fuel load was probably carried for that flight. Finally, I have heard that just keeping the nose off the ground for longer than normal after touchdown in a 747 can yield some pretty impressive aerodynamic breaking. Anyone of the above scenarios could have been why you didn't experience the roar of reverse thrust; which I happen to enjoy. But look at it this way, at least you didn't wind up the same way as AF 358.
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jamesbuk
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 5:51 am

does the position of the gates depend if you use reversers. so if a pilot knew his airline was based near the end of the runway to save time he would tab on the brakes to slow down gradually to save on the taxiing time
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tinpusher007
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 7:42 am

Quoting Jamesbuk (Reply 6):
does the position of the gates depend if you use reversers. so if a pilot knew his airline was based near the end of the runway to save time he would tab on the brakes to slow down gradually to save on the taxiing time

Usually the controllers will help you along in this scenario. If they know your gate is at an area pretty far down the rwy its not uncommon to hear "good clip down the rwy, turn left at twy x and contact ground." Keeping the speed up ensures minimum time on the rwy.
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Okie
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 8:02 am

Well ANITIX87 welcome to the future.
With advent of carbon brakes, many airlines particularly the regionals/SPJ's here in the US disable or do not order their equipment with TR's.

Most of the Majors are just opening the TR's at idle and not throttling up on landing unless conditions (runway length or WX) warrant their use to save wear and tear on the equipment or for noise abatement.

From my point of view, with the advancement of technology and economics with aircraft designed for the .82 mach range with high bypass turbines we are losing some of the gee whiz stuff.

Many aircraft without or few leading edge devices.
Single panel flaps instead of the multi element flaps.
Carbon brakes, noise abatement, operator policy causing less and less use of TR's.
Very few powerbacks.
Assumed Temp/Flex/Reduced Thrust take offs.

These items quickly come to mind.

Okie
 
calpilot
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 11:09 am

I use T/R's on every landing, unless MEL'd. If the effectiveness is not required to a hige degree, then I will only use idle reverse, and not pull a lot RPM's. so as to keep the noise down.

Throughout my training, and experence, I have always felt that I want to counter out some of that foward thrust, to assest with decleration, even if only idle reverse to do it.

As said above the newer carbon breaks are very good, however if you have revers on the aircraft its there, put it to good use, right?
 
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HAWK21M
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 5:24 pm

Possible the Length of the Runway was Adequate for the Landing & Reverse thrust was not needed.Alternate one T/R coulds have been U/s & deffered under MEL.

Quoting Finkenwerder (Reply 4):
U/S = Unserviceable and I don't think TR inop is on the MEL

One T/R INOP is def under MEL.
regds
MEL
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Matt72033
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 8:47 pm

Quoting ANITIX87 (Reply 2):
If it means one side wasn't working, wouldn't the only way to know be by finding out the hard way? Meaning, the aircraft would probably have had a bad landing experience and would not be in use. I thought of that, but it doesn't seem plausible that the pilot could possibly know if one side wasn't working

i meant in the instance that the thrust reverser was U/S before the flight, this can happen and as other people have mentioned, be deffered under the MEL (Minimum Equipment List) for a certain number of flight cycles/flying hours or calender time! in this case the other thrust reverser would be 'Locked Out' so that it cant be used to create a situation of ayssimetric thrust! If this had happened the pilots would have been aware of this and would just not use reverse thrust.

Of course in the MEL it would also give you a number of operation and performance limitations, so if the runway was not as long as it was, or there was heavy rain or ice then the aircraft would be diverted or the flight may just not take place at all!

thats how i understand it......hope this helps!
 
LPLAspotter
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 8:51 pm

Quoting Okie (Reply 8):
Most of the Majors are just opening the TR's at idle and not throttling up on landing unless conditions

I know exactly what you are talking about by seeing this happen as a passenger. However, in an aircraft type like the 747, what happens in the cockcpit? Does the pilot pull back the TR levers just slgihtly for this to happen? If he/she wants full reverse do they just pull back as far as they (tr hangles) go? Please explain as this interests me.

LPLAspotter
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Matt72033
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RE: Thrust Reverse Deployment

Sun Aug 07, 2005 8:58 pm

Quoting LPLAspotter (Reply 12):
Does the pilot pull back the TR levers just slgihtly for this to happen? If he/she wants full reverse do they just pull back as far as they (tr hangles) go?

there are detents, when the reverse thrust handles are pulled back, it will slide the cowling back, or open the clam shells, this will direct any residual thrust from the engines being at idle forwards, now the handles can be slotted into normally 2 or 3 detents which spool up the engines by different amounts!

Thats my understanding, please correct me if im wrong!
 
mandargb
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RE: Thrust Reverse Deployment

Mon Aug 08, 2005 3:31 pm

Hi,
TRs are not required in many instances.
Actually some airlines have policies that TRs not be deployed unless absolutely required from safety point of view to stop in given conditions.
Not using TRs saves on engine maint.
 
BandA
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RE: Thrust Reverse Deployment

Wed Aug 10, 2005 6:50 am

In Late November of 2002 my JAL 743 flight from YVR landed in NRT w/o using Thrust Reversers, it was the first time I had ever had a landing w/o Thrust Reversers... it was interesting I was alarmed at first because I am so used to the reversers throwing me forward after takeoff but it didnt happen and we didnt slow down fast... it seemed that we went all the way to the end of the runway before turning into a taxiway... talk about a LOOOONG taxi to the gates at NRT!
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HAWK21M
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RE: Thrust Reverse Deployment

Wed Aug 10, 2005 6:04 pm

Quoting BandA (Reply 15):
talk about a LOOOONG taxi to the gates at NRT!

The Bright side smoother landing would be less Noise  Smile
regds
MEL
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speedracer1407
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RE: Thrust Reverse Deployment

Wed Aug 10, 2005 6:34 pm

I've been aboard 19 flights on CO, NW, and AA in the last 6 months, and only half of those used reverse thrust during landing. And of that half, I'd bet that only half of THOSE used any increased throttle during reversed thrust. As a passenger, there's a clear difference between a flight idle reverse thrust deployment, and a big stab of throttle during reverse, mostly in noise. Seems to me like, in the past, EVERY landing involved reverse thrust. But with recent concerns about fuel economy and reduced cost via engine wear, many flights seem to rely on wheel brakes alone.

I find none of this frightening, or disturbing, as the actual G-force felt during wheel braking seems roughly the same as reverse thrust landings.

I think many leisure flyers who are used to the old days of big, loud, full or partial reverse thrust braking action find it difficult to accept that wheel braking makes up the majority of braking action in any normal landing....I Certainly did.
In fact, what disturbed me most on an otherwise uneventful flight with a NW DC-9 a couple months ago was the the distinct clunk and shake of the bucket reversers deploying and then stowing upon landing.

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air2gxs
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RE: Thrust Reverse Deployment

Wed Aug 10, 2005 8:16 pm

Quoting Speedracer1407 (Reply 17):
I find none of this frightening, or disturbing, as the actual G-force felt during wheel braking seems roughly the same as reverse thrust landings.

If autobraking is used, then the sensation will be no different from flight to flight. The autobrake system is designed to maintain a deceleration rate regardless of method used to brake the aircraft. If reversers are used, there is less braking attributed to the brakes. If reversers are not used, the brakes handle the whole thing (except for whatever small amount the spoilers contribute).
 
Matt72033
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RE: Thrust Reverse Deployment

Thu Aug 11, 2005 2:51 am

surely its a compromise though, if you save on engine wear by not using reverse your gonna increase your brake wear and vice versa!
 
air2gxs
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RE: Thrust Reverse Deployment

Thu Aug 11, 2005 9:15 am

Brakes are cheap, engines are expensive.
 
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HAWK21M
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RE: Thrust Reverse Deployment

Thu Aug 11, 2005 3:06 pm

Quoting Matt72033 (Reply 19):
surely its a compromise though, if you save on engine wear by not using reverse your gonna increase your brake wear and vice versa!

Cost wise it would be a right decision to reduce wear to the Engine.Brake pads replacement durng Overhaul is faster & cheaper comparitively.
regds
MEL
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SlamClick
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RE: Thrust Reverse Deployment

Fri Aug 12, 2005 12:51 am

Under US regulations thrust reversers are never required.

A transport category type certificate does permit use of reverse thrust for landings and rejected takeoffs but if reverse thrust is used for certification testing then it must be operable and cannot be deferred on the MEL. So a crew would be in violation making a landing, or committing to a takeoff where reverse thrust would be required to stop safely.

What this means is that any time you see reverse thrust being used it was not truly needed, in the sense that without it you'd have gone off the end. Rather, it was used to save brakes or to turn off before the last possible exit. In other words, reverse thrust was supplemental braking. Most lay people greatly overestimate the importance of thrust reversers.

As has been noted above there may be technical reasons or cultural (as in the airline's culture) for not using it. Airports may discourage high power in reverse just as communities along our highways may have signs for truck drivers to go easy on the Jake Brake (engine exhaust brake)
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HAWK21M
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RE: Thrust Reverse Deployment

Fri Aug 12, 2005 1:48 pm

Quoting SlamClick (Reply 22):
As has been noted above there may be technical reasons or cultural (as in the airline's culture) for not using it. Airports may discourage high power in reverse just as communities along our highways may have signs for truck drivers to go easy on the Jake Brake (engine exhaust brake)

Noise Restrictions have still not reached this part of the World Aviation wise as yet.I've heard its quite strict out there.
regds
MEL
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