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Reverse Thrust: How Often?  
User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Posted (8 years 5 months 2 days 16 hours ago) and read 4472 times:

A few years ago we landed in ATH on a BA 757 and no reverse thrust. since then, ive noticed on occasion reverse thrust isn't always used. could this be to Foreign object damage, hazards, certain requirements, or just choice of rolling to the last taki way therefore eliminating the need? is it due to engine wear?

comments appriciated!

ps- what is "idle" reverse?


121
38 replies: All unread, showing first 25:
 
User currently offlineRichardPrice From , joined Dec 1969, posts, RR:
Reply 1, posted (8 years 5 months 2 days 16 hours ago) and read 4461 times:

These days, brakes are cheaper to maintain than engines, so the extra wear and tear thrust reversing puts on engines arent worth it.

User currently offlineTristarSteve From Sweden, joined Nov 2005, 4000 posts, RR: 34
Reply 2, posted (8 years 5 months 2 days 15 hours ago) and read 4384 times:

Perhaps your aircraft had a U/S Reverser on your side.
Thrust reverse is normally deployed to Reverse Idle, but only powered up on a short runway.


User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 3, posted (8 years 5 months 2 days 15 hours ago) and read 4380 times:

As of my last duty day it was still policy here to use reverse thrust every landing where it was not prohibited.


Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineAvioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 4, posted (8 years 5 months 2 days 15 hours ago) and read 4362 times:

The two companies I've been with that actually studied brakes vs reverse found a significant savings using reverse thrust over replacing brakes. (One was a very old "legacy" airline and one a newer company.)
Unless you base engine life and cycle count on power lever cycles the acceleration of the engine in reverse isn't any different than in normal operation aside from the translating sleeve or clamshell movements.
I'm personally not aware of any increased wear on the engine in reverse over normal thrust (BR-715 excepted of course).
These are just my own personal experience based views of course... Smile



One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently offlineBa299 From United Kingdom, joined Jun 2003, 173 posts, RR: 1
Reply 5, posted (8 years 5 months 2 days 13 hours ago) and read 4327 times:

At BA our policy are: Idle reverse except in case on runway contamination, autoland.

User currently offlineGreasespot From Canada, joined Apr 2004, 3079 posts, RR: 20
Reply 6, posted (8 years 5 months 2 days 11 hours ago) and read 4283 times:

Quoting HighFlyer9790 (Thread starter):
ive noticed on occasion reverse thrust isn't always used. could this be to Foreign object damage, hazards, certain requirements, or just choice of rolling to the last taki way therefore eliminating the need? is it due to engine wear?

 no 

Many airports in Europe severly restrict TR use under normal condtions.

A TR requires very low MTCE and it is much cheaper to use it than brakes....Especially at weights.

Since you do not count the time the TR is used it does not add wear and tear on it. After 6 years in an engine shop I have yet to see an engine that failed due to TR use.....In this day and age most engines come into a shop because a disk has reached it scrap life....



Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"
User currently offlineB747FE From Hong Kong, joined Jun 2004, 230 posts, RR: 4
Reply 7, posted (8 years 5 months 2 days 10 hours ago) and read 4252 times:

Quoting Greasespot (Reply 6):
In this day and age most engines come into a shop because a disk has reached it scrap life....

Indeed.
But depend on the company policy/SOP. For us, 747 classic, steel brakes, short hops/quick turn-around, we are supposed tu use T/R as necesary and minimum brakes.

Regards,

B747FE.



"Flying is more than a sport and more than a job; flying is pure passion and desire, which fill a lifetime"
User currently offlineVC-10 From United Kingdom, joined Oct 1999, 3701 posts, RR: 34
Reply 8, posted (8 years 5 months 2 days 9 hours ago) and read 4238 times:
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If the a/c has carbon brakes it is more economical to refrain from using Rev Thrust.

Carbon brakes have a optimum operating temperature range. Using Rev Thrust delays the brakes reaching that temp range which increases brake wear & shortens their life. If the brake unit doesn't reach the manufacturers certified o/haul life when there is no defect, they will charge the airline more for the ensueing o/haul.


User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Reply 9, posted (8 years 5 months 2 days 8 hours ago) and read 4232 times:

Quoting B747FE (Reply 7):
In this day and age most engines come into a shop because a disk has reached it scrap life....

Now that we have established that, how powerful is reverse thrust? can plane land with no brakes at all? plus, to my knowledge, RT is actually just the re-direction of the air flow/exhaust....right?



121
User currently offlineAmericanAirFan From United States of America, joined Jun 2004, 408 posts, RR: 3
Reply 10, posted (8 years 5 months 2 days 4 hours ago) and read 4206 times:

Quoting HighFlyer9790 (Reply 9):
Now that we have established that, how powerful is reverse thrust? can plane land with no brakes at all? plus, to my knowledge, RT is actually just the re-direction of the air flow/exhaust....right?

I know WN doesn't use Autobrakes on landing but just use reverse thrust but they do apply manual braking once at a slower speed. So yes on a fairly lengthened runway you can stop without brakes but just reverse thrust and on the MD-80s they have the clamshells and are able to do a powerback.

I have another question. Though noone has beleive me you might here I was enroute AUS-ELP on a WN 737-300 and when we landed no airbrakes were used but reverse thrust was. then we flew ELP-LAX when I was about to get off the plane I asked the pilot why he hadnt deployed the spoilers at ELP and he had no idea that they didn't I have a picture with the runway bluring by and no airbrakes but full flaps and we had reverse thrust. So what kind of impact does not having the airbrakes have on landing in regular conditions? All I know is that they dump the lift and put the weight reassuringly onto the wheels rather than the wings. Can anybody explain?

Interesting topic and good question btw.

-AmericanAirFan



"American 1881 Cleared For Takeoff One Seven Left"
User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Reply 11, posted (8 years 5 months 1 day 17 hours ago) and read 4113 times:

Quoting AmericanAirFan (Reply 10):
Interesting topic and good question btw.

Thanks a lot...you guys certainly have good answers too.  bigthumbsup 

Quoting AmericanAirFan (Reply 10):
So what kind of impact does not having the airbrakes have on landing in regular conditions? All I know is that they dump the lift and put the weight reassuringly onto the wheels rather than the wings. Can anybody explain?

yes, as far as i know the spoilers bisturb the airflow over the wing ensuring that the plane remains on the ground. it dumps lift. remember the jetblue emergency landing with the twisted nose gear at LAX? he didnt use spoilers because it enabled him to keep the nose wheel off the ground for a longer amount time. anyhow, spoilres are always set to auto, and they auto deploy on landing.

regards!



121
User currently offlineSkyslave From United States of America, joined Oct 2005, 44 posts, RR: 0
Reply 12, posted (8 years 5 months 1 day 13 hours ago) and read 4076 times:

Quoting AmericanAirFan (Reply 10):
Now that we have established that, how powerful is reverse thrust? can plane land with no brakes at all? plus, to my knowledge, RT is actually just the re-direction of the air flow/exhaust....right?

My dad is a 747-400 captain. He was telling me that with the combonation of aerodynamic breaking (nose up attitude, ground spoilers etc..) and thrust reversers, he rarely has to use the breaks at all.


User currently offlineHAWK21M From India, joined Jan 2001, 31679 posts, RR: 56
Reply 13, posted (8 years 5 months 18 hours ago) and read 3976 times:

Brakes are rarely used,as compared with T/Rs.But then the Exceptions can be Regulatory based,SOP.
regds
MEL



Think of the brighter side!
User currently offlineEssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 14, posted (8 years 5 months 16 hours ago) and read 3954 times:

Quoting HAWK21M (Reply 13):
Brakes are rarely used,as compared with T/Rs.But then the Exceptions can be Regulatory based,SOP.
regds
MEL

??? I Don't agree w/ that at all.

1. Most US operators use autobrakes as part of the landing profile (Boeing or Airbus), which means brakes are applied as soon as the a/c knows it's on the ground and dissipate the majority of the kinetic energy.

2. With fuel costs where they are, brakes are cheaper than TRs.


User currently offlineKAUSpilot From United States of America, joined Jan 2002, 1958 posts, RR: 33
Reply 15, posted (8 years 5 months 14 hours ago) and read 3940 times:

Our company SOP is to deploy "the buckets" on every landing but only to spool up the engines if it's necessary to stop in a safe distance.

I could count on one hand the number of times I've spooled up the reversers in the past 6 months.

I've noticed that pilots on the 737's I ride on regularly are spooling up their reversers less and less as well. The fuel burn and engine wear and tear caused by using substantial reverse thrust power has been determined to be more expensive than the wear and tear caused by consistent break usage.


User currently offlineHighpeaklad From United Kingdom, joined Aug 2004, 538 posts, RR: 0
Reply 16, posted (8 years 5 months 14 hours ago) and read 3937 times:

I've just flown MAN-JFK and return on a BA 767 and no reverse seemed to be used on either landing. I couldn't see the engines so possibly idle reverse was engaged, would this give a noticable change in engine noise in the cabin?

Chris



Don't try to keep up with the Joneses - bring them down to your level !
User currently offlineKaddyuk From Wallis and Futuna, joined Nov 2001, 4126 posts, RR: 26
Reply 17, posted (8 years 5 months 14 hours ago) and read 3931 times:

As VC-10 said, carbon brakes are temperature sensitive... Unlike the steel brakes you find on old aircraft, the carbon brakes work better the hotter they are... Not only that, but it keeps noise down around the airport and makes local residents happy...

If you use reverse thrust AND braking, your brake unit might last 1500 cycles. If you just use brakes with no reverse thrust, well, i've seen units as high as 2400 cycles... the difference is MASSIVE!

and FYI, each landing takes about one thousandth of an inch off a brake unit...



Whoever said "laughter is the best medicine" never had Gonorrhea
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17029 posts, RR: 67
Reply 18, posted (8 years 5 months 12 hours ago) and read 3917 times:

Quoting Highpeaklad (Reply 16):
I've just flown MAN-JFK and return on a BA 767 and no reverse seemed to be used on either landing. I couldn't see the engines so possibly idle reverse was engaged, would this give a noticable change in engine noise in the cabin?

Idle reverse would likely not make much of a noticeable noise.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineAmericanAirFan From United States of America, joined Jun 2004, 408 posts, RR: 3
Reply 19, posted (8 years 5 months 12 hours ago) and read 3909 times:

Quoting KAUSpilot (Reply 15):
Our company SOP is to deploy "the buckets" on every landing but only to spool up the engines if it's necessary to stop in a safe distance.

I could count on one hand the number of times I've spooled up the reversers in the past 6 months.

I've noticed that pilots on the 737's I ride on regularly are spooling up their reversers less and less as well. The fuel burn and engine wear and tear caused by using substantial reverse thrust power has been determined to be more expensive than the wear and tear caused by consistent break usage.

To add more to this discussion at AUS I always see the Delta Express and Continental Express and American Eagle don't use reverse thrust when landing on 17L and I can usually hear the brakes gripping the wheels very nicely. KAUSpilot I notice you are an ERJ pilot so can you explain on this at all I've only noticed that the ERJs dont even put R/T at idle thrust.



"American 1881 Cleared For Takeoff One Seven Left"
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17029 posts, RR: 67
Reply 20, posted (8 years 5 months 12 hours ago) and read 3906 times:

Quoting AmericanAirFan (Reply 19):
KAUSpilot I notice you are an ERJ pilot so can you explain on this at all I've only noticed that the ERJs dont even put R/T at idle thrust.

There's a simple explanation. Some ERJs don't have reverse thrust capability. It's a customer option.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineVikkyvik From United States of America, joined Jul 2003, 9943 posts, RR: 26
Reply 21, posted (8 years 5 months 9 hours ago) and read 3878 times:
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Keep in mind also that thrust reverse is generally only used at higher speeds (generally above either 60 or 80 kts I think - I forget which). At lower speeds you risk the engine reingesting its own exhaust. So most of the braking power at lower speeds comes from the wheel brakes.

Also, autobrakes are designed so that each setting gives you a certain deceleration rate. So if you also use some thrust reverse, there will be less wheel brake pressure, and when you stow the reversers, the wheel brakes will pick up the slack.

Ground spoilers are used both as airbrakes, and also to dump the lift generated by the wing, thus putting more weight on the wheels and increasing wheel brake effectiveness.

At least, that's my understanding. Please correct me if I'm wrong.

~Vik



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlineKAUSpilot From United States of America, joined Jan 2002, 1958 posts, RR: 33
Reply 22, posted (8 years 5 months 8 hours ago) and read 3866 times:

Quoting AmericanAirFan (Reply 19):
KAUSpilot I notice you are an ERJ pilot so can you explain on this at all I've only noticed that the ERJs dont even put R/T at idle thrust.

Yep, some of eagles RJ's don't have the T.R's installed, and it was their policy for a long time not to use them at all. However, I believe a runway overrun incident at DSM back in late '04 caused them to revise this policy; I believe they now deploy the buckets on aircraft which are so equipped at the pilot's discretion.

All of Expressjet's aircraft are equipped with T.R's. It's always been their policy to deploy them, but not spool them up unless necessary.


User currently offlinePihero From France, joined Jan 2005, 4407 posts, RR: 76
Reply 23, posted (8 years 4 months 4 weeks 1 day 23 hours ago) and read 3822 times:
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Quoting Skyslave (Reply 12):
My dad is a 747-400 captain. He was telling me that with the combonation of aerodynamic breaking (nose up attitude, ground spoilers etc..) and thrust reversers, he rarely has to use the breaks at all.

That technique is an absolute NO-NO these days.



Contrail designer
User currently offlineFDXMECH From United States of America, joined Mar 2000, 3251 posts, RR: 34
Reply 24, posted (8 years 4 months 4 weeks 17 hours ago) and read 3693 times:

Quoting Kaddyuk (Reply 17):
If you use reverse thrust AND braking, your brake unit might last 1500 cycles. If you just use brakes with no reverse thrust, well, i've seen units as high as 2400 cycles... the difference is MASSIVE!

and FYI, each landing takes about one thousandth of an inch off a brake unit...

The cost of overhauling a carbon brake is also massive. FDX put out some info a few years ago saying a new carbon stack cost approx $40,000.



You're only as good as your last departure.
25 A/c train : Bend the bracket, put some swan necks on the wear pin, you'll get a few more landings out of it! Has anyone seen the PPE requirements for changing a c
26 HighFlyer9790 : So, sometimes it may look like a RT landing, but you can manually reverse a controlled amount? (if that makes any sense)
27 KAUSpilot : Exactly...there is a "detent" in each throttle (or thrust lever as we call it) column....to operate the engines in reverse, you have to pull upward o
28 HighFlyer9790 : Ok thanks...I knew how they were activated and now it makes sense...
29 Post contains links HighFlyer9790 : btw, http://www.msm.cam.ac.uk/phase-trans/mphil/Trent1/img015.JPG http://www.aviationshop.com.au/avfacts/editorial/bgt/tr6c.jpg These are some neat di
30 Starlionblue : On FBW Airbi you just pull back beyond idle.
31 Post contains links and images Vikkyvik : Correct me if I'm wrong, but I believe that on the Airbus there are also levers to engage the reversers, located forward of the thrust levers. I thin
32 KAUSpilot : Some of my Eagle friends would like me to correct myself about their TR policy:
33 Post contains links and images LTU932 : Not on the A32X it seems. However the A330, along with the A340 does have those extra levers for the T/Rs, while the A380 only has two of those extra
34 Mir : Idle reverse is pretty much what it sounds like - the reversers are deployed, and the engine is at idle power. I believe that there are levers that y
35 Post contains links and images HighFlyer9790 : The A320 has to release levers to allow the throttles to go back to RT position. View Large View MediumPhoto © Quinn Savit
36 Post contains images HighFlyer9790 : Here are two diagrams...the secong shows the A320 style throttles... highlyer
37 Post contains links HighFlyer9790 : Here are some good views of some RT action... A300 http://www.flightlevel350.com/video_streaming.php?id=5804 A346 http://www.flightlevel350.com/video_
38 Post contains links B757capt : Well there is a little more to the WN story. Orginally Southwest operated the 737-200,-300. The SOP was written for the -200 which some had no autobr
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