laumanu
Topic Author
Posts: 1
Joined: Sun Oct 21, 2018 2:51 pm

Reverse thrust practice

Thu Oct 25, 2018 10:57 am

Hello everybody

I've been reading here for years, but haven't posted so far... :-)
In ZRH, there are SIA and UAE A380s landing. I'm not sure, but I think that I can only hear reverse thrusters on the UAEs when they land.
Is this something that airlines do handle differently or is this even the pilot's choice?

Thanks very much for clarification.

Best regards, Manuel
 
ChrisKen
Posts: 545
Joined: Tue Aug 05, 2008 11:15 pm

Re: Reverse thrust practice

Thu Oct 25, 2018 11:30 am

Company SOPs may encourage less vigorous use where appropriate as it saves wear & tear on the engine; airports may request discretion for noise abatement but ultimately it's the aircraft commander's choice. I suspect SQ will at the very least will mandate entering 'reverse idle' on touchdown, EK pilots doing the same but electing to venture further in to the reverse range.
 
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zeke
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Re: Reverse thrust practice

Thu Oct 25, 2018 1:07 pm

The UAE flight being a shorter flight maybe landing with more passengers and cargo. Higher weights would mean higher approach speed, hence more kinetic energy to get rid of on landing.
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evank516
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Joined: Wed Mar 01, 2017 12:15 am

Re: Reverse thrust practice

Thu Oct 25, 2018 1:13 pm

I notice with Airbus aircraft, at least the narrowbodies, that reverse thrust is less audible if you're seated behind the wings. Sometimes even over the wings you can't hear it, but with Boeing narrowbodies it's quite a bit more audible.
 
AA737-823
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Re: Reverse thrust practice

Fri Oct 26, 2018 4:36 am

evank516 wrote:
I notice with Airbus aircraft, at least the narrowbodies, that reverse thrust is less audible if you're seated behind the wings. Sometimes even over the wings you can't hear it, but with Boeing narrowbodies it's quite a bit more audible.


That doesn't make any sense, particularly given that between the two manufacturers, engines and cowls/reversers are often identical or similar.
I.e., you can get a GE CF6 on a 767 or A330, both with translating sleeve reverse...
Or a CFM56 on a 737 versus the IAE2500 on the A320 with virtually identical reverser design.

Now, the Airbus cabins are often quieter across the board. But reverse is pretty much the same either way- you're blowing many thousand pounds of thrust out the sides of the engines.
 
shamrock137
Posts: 289
Joined: Mon Jul 25, 2005 7:10 am

Re: Reverse thrust practice

Fri Oct 26, 2018 9:34 pm

ChrisKen wrote:
Company SOPs may encourage less vigorous use where appropriate as it saves wear & tear on the engine; airports may request discretion for noise abatement but ultimately it's the aircraft commander's choice. I suspect SQ will at the very least will mandate entering 'reverse idle' on touchdown, EK pilots doing the same but electing to venture further in to the reverse range.


Bingo. There was a time when fuel spiked and during the recession some airlines were advocating no reverse at all, save fuel and wear and tear on the engines. Most airlines I know of now though say use idle reverse on every landing and add thrust as needed. Thought behind this is with idle reverse you're still getting the benefit of fuel savings, but can spool up the engines quickly if needed, vs not using them then needing them and having to wait for them to deploy and the engines to spool up.
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Acey
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Re: Reverse thrust practice

Sat Oct 27, 2018 3:16 am

Funny to watch 737 land on the 14,000 foot runway at YYC. WS lands and uses and absolute ton of reverse no matter the conditions, and Air Canada 737 or Airbus will land in behind and use hardly any. Definitely varies by company...
If a man hasn't discovered something that he will die for, he isn't fit to live. -- Martin Luther King, Jr.
 
e38
Posts: 547
Joined: Sun May 04, 2008 10:09 pm

Re: Reverse thrust practice

Sat Oct 27, 2018 5:47 pm

at the company where I work, it is standard operating procedure (SOP) to use full reverse thrust on every landing. Primarily, it is an operational check of the reverse thrust system. On the fleet to which I am assigned (A319/A320/A321) full reverse thrust is initiated shortly after main gear touchdown. At 80 KIAS, we smoothly reduce to idle reverse, and then come out of reverse shortly thereafter when N1 approximates idle thrust.
We never exit the runway with the thrust reversers still deployed.

The SOP allows pilot judgment to use less than full reverse thrust in certain situations under favorable conditions. An example I can think of quickly is landing at El Paso International Airport (KELP) on Runway 22 (runway length approximately 12,000 feet) and the terminal building is located at the far end of the runway. Under day, VMC, dry runway conditions, it would be acceptable to use idle reverse after landing and exit the runway at Taxiway H or F.

This would be the exception. Normal procedure is full reverse thrust on every landing.

e38
 
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TOGA10
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Re: Reverse thrust practice

Sat Oct 27, 2018 6:23 pm

It also depends on the airport. Geneva (GVA) for example states. Only use reverse thrust for safety reasons. The rwy being 3900M long, normally idle or no reverse would be enough for 95% of the aircraft coming in. Obviously, technical issues or a contaminated runway make for a different scenario.
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LimaFoxTango
Posts: 877
Joined: Wed Jun 16, 2004 11:33 pm

Re: Reverse thrust practice

Sat Oct 27, 2018 10:47 pm

e38 wrote:
at the company where I work, it is standard operating procedure (SOP) to use full reverse thrust on every landing. Primarily, it is an operational check of the reverse thrust system. On the fleet to which I am assigned (A319/A320/A321) full reverse thrust is initiated shortly after main gear touchdown. At 80 KIAS, we smoothly reduce to idle reverse, and then come out of reverse shortly thereafter when N1 approximates idle thrust.
We never exit the runway with the thrust reversers still deployed.

The SOP allows pilot judgment to use less than full reverse thrust in certain situations under favorable conditions. An example I can think of quickly is landing at El Paso International Airport (KELP) on Runway 22 (runway length approximately 12,000 feet) and the terminal building is located at the far end of the runway. Under day, VMC, dry runway conditions, it would be acceptable to use idle reverse after landing and exit the runway at Taxiway H or F.

This would be the exception. Normal procedure is full reverse thrust on every landing.

e38


I'm willing to bet your company has had a runway overrun/excursion at some point in the past hence such draconian exercise.
You are said to be a good pilot when your take-off's equal your landings.
 
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Starlionblue
Posts: 18703
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Re: Reverse thrust practice

Sun Oct 28, 2018 4:10 am

laumanu wrote:
Hello everybody

I've been reading here for years, but haven't posted so far... :-)
In ZRH, there are SIA and UAE A380s landing. I'm not sure, but I think that I can only hear reverse thrusters on the UAEs when they land.
Is this something that airlines do handle differently or is this even the pilot's choice?

Thanks very much for clarification.

Best regards, Manuel


"Thrust reversers", not "reverse thrusters". We're not conning the Enterprise. ;)
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
tommy1808
Posts: 9164
Joined: Thu Nov 21, 2013 3:24 pm

Re: Reverse thrust practice

Mon Oct 29, 2018 11:36 am

shamrock137 wrote:
ChrisKen wrote:
Company SOPs may encourage less vigorous use where appropriate as it saves wear & tear on the engine; airports may request discretion for noise abatement but ultimately it's the aircraft commander's choice. I suspect SQ will at the very least will mandate entering 'reverse idle' on touchdown, EK pilots doing the same but electing to venture further in to the reverse range.


Bingo. There was a time when fuel spiked and during the recession some airlines were advocating no reverse at all, save fuel and wear and tear on the engines


Carbon brakes also may play a part in this, as they pretty much wear per use and not per energy absorbed, so there is no meaningfully reduced break wear from applying trust reversers.

Best regards
Thomas
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mmo
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Re: Reverse thrust practice

Mon Oct 29, 2018 1:09 pm

tommy1808 wrote:

Carbon brakes also may play a part in this, as they pretty much wear per use and not per energy absorbed, so there is no meaningfully reduced break wear from applying trust reversers.

Best regards
Thomas


Care to tell me where you are getting this information? I ask because you are wrong.

1) Steel brakes wear "per use". How else would they work?

2) Reverse thrust if much more effective at higher speeds. If you take auto brakes into the equation, with the exception of MAX, the other settings provide a deceleration rate so any reversing at all will result in less wheel brake use.

3) What you will find is one big reason for the use of minimum reverse is for a couple of reasons. It is not uncommon for airlines to lease brakes and they are guaranteed a certain amount of wear. So, it is cheaper to use the wheel brakes than it is the reverse thrust.
In addition, the use of reverse thrust had a detrimental effect on the engine life. There is also more noise generated and in today's world, you want to be a good neighbour and be as quiet as possible as you can.
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evank516
Posts: 1556
Joined: Wed Mar 01, 2017 12:15 am

Re: Reverse thrust practice

Mon Oct 29, 2018 1:24 pm

AA737-823 wrote:
evank516 wrote:
I notice with Airbus aircraft, at least the narrowbodies, that reverse thrust is less audible if you're seated behind the wings. Sometimes even over the wings you can't hear it, but with Boeing narrowbodies it's quite a bit more audible.


That doesn't make any sense, particularly given that between the two manufacturers, engines and cowls/reversers are often identical or similar.
I.e., you can get a GE CF6 on a 767 or A330, both with translating sleeve reverse...
Or a CFM56 on a 737 versus the IAE2500 on the A320 with virtually identical reverser design.

Now, the Airbus cabins are often quieter across the board. But reverse is pretty much the same either way- you're blowing many thousand pounds of thrust out the sides of the engines.


It could be the fact that the cabins are quieter, or the way the reverse thrust buckets are designed. Some slide backwards and others have these little vents open up on the engines.
 
tommy1808
Posts: 9164
Joined: Thu Nov 21, 2013 3:24 pm

Re: Reverse thrust practice

Mon Oct 29, 2018 2:39 pm

mmo wrote:
tommy1808 wrote:

Carbon brakes also may play a part in this, as they pretty much wear per use and not per energy absorbed, so there is no meaningfully reduced break wear from applying trust reversers.

Best regards
Thomas


Care to tell me where you are getting this information? I ask because you are wrong.

1) Steel brakes wear "per use". How else would they work?


I didn't phrase it properly....

Carbon brakes wear per break application, how much energy each application has to eat up is basically irrelevant.
Steel breakes wear per energy intake, how many applications that is spread over is basically irrelevant.

Hence with steel breakes TR application reduces break wear, ofsetting its cost somewhat, while with carbon breakes it doesn't and you only get shorter stopping distances.

No idea where I originally got that from, but not hard to find sources:
http://code7700.com/carbon-carbon_brakes.htm

Best regards
Thomas
This Singature is a safe space......
 
mmo
Posts: 1637
Joined: Thu Apr 18, 2013 3:04 pm

Re: Reverse thrust practice

Mon Oct 29, 2018 8:22 pm

tommy1808 wrote:



Carbon brakes wear per break application, how much energy each application has to eat up is basically irrelevant.
Steel breakes wear per energy intake, how many applications that is spread over is basically irrelevant.

Hence with steel breakes TR application reduces break wear, ofsetting its cost somewhat, while with carbon breakes it doesn't and you only get shorter stopping distances.

No idea where I originally got that from, but not hard to find sources:
http://code7700.com/carbon-carbon_brakes.htm

Best regards
Thomas


I guess I don't see your point. Both carbon and steel brakes can only absorb a certain amount of energy. If it is in one brake application or 100 brake applications is really irrelevant as they both only have a certain amount of energy absorption.

One drawback with carbon brakes is they have to be at a certain operating temperature to work at their best efficiency while steel brakes work best cold.

Regardless, your comment about reverse thrust "no meaningfully reduced break wear from applying trust reversers." is just incorrect.
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