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AA MD-80 No Thrust Reverse?  
User currently offlinemke717spotter From United States of America, joined Dec 2005, 2438 posts, RR: 5
Posted (1 year 6 months 2 weeks 1 day 18 hours ago) and read 5391 times:

Since May 2011 I've been on six AA MD-80 flights (including ORD-DFW-TUS yesterday) and every time during landing it seemed like there was no thrust reverse. It was completely silent. since it sounded like the may have been minimally kicked it, but it paled in comparison to my recent DL MD-80 flight. Does AA have some sort of fuel-saving policy where they're not MD-80 pilots aren't supposed to use thrust reverse? I could've sworn I remember something like this about AE and the ERJs.


Will you watch the Cleveland Browns and the Detroit Lions on Sunday? Only if coach Eric Mangini resigned after a loss.
29 replies: All unread, showing first 25:
 
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16991 posts, RR: 67
Reply 1, posted (1 year 6 months 2 weeks 1 day 17 hours ago) and read 5359 times:

Maybe they only used idle reverse. Makes way less noise and wears on the engines less. Don't think the fuel savings are that great. And if you have to roll down the runway a ways you might as well coast.

If memory serves reversers are optional on the ERJ.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinebond007 From United States of America, joined Mar 2005, 5397 posts, RR: 8
Reply 2, posted (1 year 6 months 2 weeks 1 day 14 hours ago) and read 5279 times:

Quoting Starlionblue (Reply 1):
Maybe they only used idle reverse.

Most likely the correct answer.

On a dry runway, there is a negligible reduction in stopping distance when using anything but idle reverse.


Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlinemke717spotter From United States of America, joined Dec 2005, 2438 posts, RR: 5
Reply 3, posted (1 year 6 months 2 weeks 1 day 13 hours ago) and read 5223 times:

What exactly is idle reverse?


Will you watch the Cleveland Browns and the Detroit Lions on Sunday? Only if coach Eric Mangini resigned after a loss.
User currently offlinebond007 From United States of America, joined Mar 2005, 5397 posts, RR: 8
Reply 4, posted (1 year 6 months 2 weeks 1 day 13 hours ago) and read 5211 times:

Quoting mke717spotter (Reply 3):
What exactly is idle reverse?

The thrust reversers are activated, but engine is left at idle. This has the effect of eliminating the residual thrust from the idle engines - the engines will always be providing a small amount of forward thrust at idle otherwise, so the effect is to kill all forward thrust.

It is also very quiet  

edited: Presumably, depending on the type of thrust reversers, there is also a small drag component added.

Jimbo

[Edited 2013-01-08 19:15:02]


I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineprebennorholm From Denmark, joined Mar 2000, 6385 posts, RR: 54
Reply 5, posted (1 year 6 months 2 weeks 1 day 13 hours ago) and read 5191 times:

Quoting mke717spotter (Thread starter):
Since May 2011 I've been on six AA MD-80 flights (including ORD-DFW-TUS yesterday) and every time during landing it seemed like there was no thrust reverse.

In Europe this has been common practice during the last 20-25 years. In many airports use of reversers is prohibited in order to reduce noise (except in case of emergencies of course).

Reversers are engaged, and often the engines are spooled up to slightly above idle. That doesn't actually perform any meaningful brake action, but it reduces spool up time significantly in case of failure on the wheel brakes.

Quoting Starlionblue (Reply 1):
Don't think the fuel savings are that great.

In many cases I think that the wear of the brakes is more costly than the fuel saving on not using the reversers. At least I have noticed that SK sometimes use reversers on remote combined military airfields, where noise doesn't really matter, even when the runway is twice as long as needed for landing the MD-80. But when reversers are banned, they have no choice.



Always keep your number of landings equal to your number of take-offs, Preben Norholm
User currently offlinevikkyvik From United States of America, joined Jul 2003, 9767 posts, RR: 27
Reply 6, posted (1 year 6 months 2 weeks 1 day 12 hours ago) and read 5161 times:
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Quoting bond007 (Reply 2):
On a dry runway, there is a negligible reduction in stopping distance when using anything but idle reverse.

Is that what you meant to say? Makes it sound like idle reverse has a more-than-negligible reduction in stopping distance.  
Quoting bond007 (Reply 4):
This has the effect of eliminating the residual thrust from the idle engines - the engines will always be providing a small amount of forward thrust at idle otherwise, so the effect is to kill all forward thrust.

Just a note - this might be true on airplanes with clamshell-style reversers (which I think the MD-80 has) that reverse the bypass and core flow, but on most modern turbofans, the reversers only affect the bypass flow. So there is still some forward thrust, even if it's a small percentage of the overall thrust on high-bypass engines.

Quoting prebennorholm (Reply 5):
In many cases I think that the wear of the brakes is more costly than the fuel saving on not using the reversers. At least I have noticed that SK sometimes use reversers on remote combined military airfields, where noise doesn't really matter, even when the runway is twice as long as needed for landing the MD-80. But when reversers are banned, they have no choice.

Isn't part of the reasoning that it's better to use newer carbon brakes more, as they're more efficient heated up? Not an expert in that myself.



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlinelonghauler From Canada, joined Mar 2004, 4911 posts, RR: 43
Reply 7, posted (1 year 6 months 2 weeks 1 day 11 hours ago) and read 5130 times:

Quoting prebennorholm (Reply 5):
In many cases I think that the wear of the brakes is more costly than the fuel saving on not using the reversers.

Not if the airline leases the brakes on a "per landing" basis. Then the pilots are encouraged, where safe, to use idle reverse and moderate wheel braking.

Airlines leasing brakes, are a lot more common than one would imagine.



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlinefreeze3192 From United States of America, joined Oct 2006, 164 posts, RR: 0
Reply 8, posted (1 year 6 months 2 weeks 1 day 8 hours ago) and read 5046 times:

IIRC the policy at Eagle is that reversers are only to be used on runways less than 7000 ft, when the runway is contaminated or if the PIC deems it necessary.

At ExpressJet, on the ERJ fleet their policy is different. Reversers almost all the time.



"A passenger bets his life that his pilot is a worthy heir to an ancient tradition of excellence and professionalism."
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 9, posted (1 year 6 months 2 weeks 1 day 8 hours ago) and read 5043 times:

Quoting vikkyvik (Reply 6):
Isn't part of the reasoning that it's better to use newer carbon brakes more, as they're more efficient heated up? Not an expert in that myself.

Steel brakes wear in proportion to the amount of energy absorbed. Carbon brakes wear in proportion to the number of applications, and they have better performance when they're warm. As a result, carbon brakes don't really care if you brake hard or soft so you might as well brake hard to warm them up. Your brake wear is no worse and you reduce engine/reverser wear.

Tom.


User currently offlineKC135Hydraulics From United States of America, joined Nov 2012, 289 posts, RR: 0
Reply 10, posted (1 year 6 months 2 weeks 1 day 7 hours ago) and read 5014 times:

We have carbon brakes on the KC-135 and they are excellent. The aircraft has no thrust reverses. Brakes can stay on the aircraft for several years depending on aircraft utilization. They are changed more for cracked heat shields rather than wear from what I have seen working in the back shop.

User currently offlinebond007 From United States of America, joined Mar 2005, 5397 posts, RR: 8
Reply 11, posted (1 year 6 months 2 weeks 1 day 4 hours ago) and read 4966 times:

Quoting vikkyvik (Reply 6):

Quoting bond007 (Reply 2):
On a dry runway, there is a negligible reduction in stopping distance when using anything but idle reverse.

Is that what you meant to say? Makes it sound like idle reverse has a more-than-negligible reduction in stopping distance.

It is what I meant to say, but not what I meant it to sound like  

What I meant, is that on a dry, uncontaminated runway, the reduction in stopping distance using reverse thrust for most airliners, is a few hundred feet ....even on full reverse thrust!

On contaminated runways it is significant, but there are few advantages to using full reverse thrust on a dry runway.


Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlinemesaflyguy From United States of America, joined Dec 2012, 2926 posts, RR: 4
Reply 12, posted (1 year 6 months 2 weeks 9 hours ago) and read 4717 times:
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Quoting freeze3192 (Reply 8):

So they don't use them at LGA? I thought I saw one or two ERJs (both 145s) use reverse thrusters when they landed a few weeks ago, but I could be wrong.



\________(---)________/ :) World's most beautiful aircraft: 757-200, MD-88/90, E-190, A321
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16991 posts, RR: 67
Reply 13, posted (1 year 6 months 2 weeks 9 hours ago) and read 4716 times:

Quoting mesaflyguy (Reply 12):
Quoting freeze3192 (Reply 8):

So they don't use them at LGA? I thought I saw one or two ERJs (both 145s) use reverse thrusters when they landed a few weeks ago, but I could be wrong.

LGA has 7000 foot runways so there should be no need. Company SOP dictates.


BTW "reverse thrusters" are for the Starship Enterprise. "Thrust reversers" are for airliners".  



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinemesaflyguy From United States of America, joined Dec 2012, 2926 posts, RR: 4
Reply 14, posted (1 year 6 months 2 weeks 9 hours ago) and read 4713 times:
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Quoting Starlionblue (Reply 13):

Really? Wow I've been saying it wrong for a long time! I've said Reverse Thrusters since the day I got into Aviation.

Either way, thanks for the information. The plane went by quick so I didn't get an excellent view of the THRUST REVERSERS. 



\________(---)________/ :) World's most beautiful aircraft: 757-200, MD-88/90, E-190, A321
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16991 posts, RR: 67
Reply 15, posted (1 year 6 months 2 weeks 6 hours ago) and read 4679 times:

Quoting mesaflyguy (Reply 14):
The plane went by quick so I didn't get an excellent view of the THRUST REVERSERS.

Hehe.  

You have to look at the what is a noun and what is an adjective. "Reverse thrusters" are "thruster" gizmos that thrust in a reverse direction, like on the Starship Enterprise or the Space Shuttle. "Thrust reverser" is a "reverser" gizmo that reverses the thrust of another gizmo.

[Edited 2013-01-10 02:43:05]


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinemesaflyguy From United States of America, joined Dec 2012, 2926 posts, RR: 4
Reply 16, posted (1 year 6 months 2 weeks 3 hours ago) and read 4631 times:
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Now I see that. Thrist Reverser makes a lot more sense.


\________(---)________/ :) World's most beautiful aircraft: 757-200, MD-88/90, E-190, A321
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16991 posts, RR: 67
Reply 17, posted (1 year 6 months 2 weeks 1 hour ago) and read 4612 times:

Quoting mesaflyguy (Reply 16):
Now I see that. Thrist Reverser makes a lot more sense.

Yeah but let's face it. Reverse thrusters are cooler. 



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinevikkyvik From United States of America, joined Jul 2003, 9767 posts, RR: 27
Reply 18, posted (1 year 6 months 1 week 6 days 23 hours ago) and read 4548 times:
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Quoting Starlionblue (Reply 13):
Quoting mesaflyguy (Reply 12):
Quoting freeze3192 (Reply 8):

So they don't use them at LGA? I thought I saw one or two ERJs (both 145s) use reverse thrusters when they landed a few weeks ago, but I could be wrong.

LGA has 7000 foot runways so there should be no need. Company SOP dictates.

I'd wager that they still open the reversers, but just leave them at idle thrust. It's a good idea, just in case you need to stop quickly.

But I don't know their procedures.



"Two and a Half Men" was filmed in front of a live ostrich.
User currently offlineMax Q From United States of America, joined May 2001, 4359 posts, RR: 19
Reply 19, posted (1 year 6 months 1 week 6 days 23 hours ago) and read 4536 times:

Quoting prebennorholm (Reply 5):

In Europe this has been common practice during the last 20-25 years. In many airports use of reversers is prohibited in order to reduce noise (except in case of emergencies of course).

I can't think of a single airport in Europe that 'prohibits' reverse.


They may request the minimal use of and / or idle reverse unless necessary.


But there is no prohibition I know of.


It makes a lot more noise to run off a wet / contaminated runway because you don't use it !



The best contribution to safety is a competent Pilot.
User currently offlineRussianJet From Belgium, joined Jul 2007, 7688 posts, RR: 21
Reply 20, posted (1 year 6 months 1 week 6 days 22 hours ago) and read 4508 times:
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Quoting Starlionblue (Reply 17):
Quoting mesaflyguy (Reply 16):
Now I see that. Thrist Reverser makes a lot more sense.

Yeah but let's face it. Reverse thrusters are cooler.

Thanks for making an otherwise very dry discussion really quite funny, guys!   



✈ Every strike of the hammer is a blow against the enemy. ✈
User currently offline737tdi From United States of America, joined Sep 2007, 783 posts, RR: 1
Reply 21, posted (1 year 6 months 1 week 6 days 20 hours ago) and read 4471 times:
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Very curious?? I fly almost weekly on my companies aircraft, alot of it in the cockpit and I can't ever remember the driver NOT using full reverse thrust. Even on long runways they use the reversers at power.

User currently offlineprebennorholm From Denmark, joined Mar 2000, 6385 posts, RR: 54
Reply 22, posted (1 year 6 months 1 week 6 days 13 hours ago) and read 4367 times:

Quoting Max Q (Reply 19):
I can't think of a single airport in Europe that 'prohibits' reverse.

They may request the minimal use of and / or idle reverse unless necessary.

I would assume that "prohibit" and "request minimal use" is the same thing in ordinary life.

Fact is that I read in a local aviation magazine some 20-25 years ago that now was the end of reverser use at CPH, like it had already been ruled at several other major airports. The NYMBYs had fought a long war and won the battle. And since that day the wonderful roar of the reverser of the SK DC-9s ended, something which I at that time enjoyed very frequently, often from the rear end of the cabin.

And I have since noticed zero use of more than slightly above idle reverse at CPH during a few hundred landings with well over a dozen airline companies. And very little use elsewhere around Europe.

On the other hand I have noticed the same airlines use reversers constantly at places like KRP and KEF, and never at CPH. KRP and KEF have fully as long runways, but they are places out in the wilderness where nobody cared about noise. And BTW, if they noticed any noise, then it was more likely the afterburners of F-15 and F-16 fighters taking off. Or in the old days, even worse, SAAB Drakens or F-104 Starfighters taking off.

Quoting mesaflyguy (Reply 12):
I thought I saw one or two ERJs (both 145s) use reverse thrusters when they landed a few weeks ago,

You must have very good eyes. Because the only way to see it is looking at the trust levers in the cockpit.

It's much easier to use the ears.  



Always keep your number of landings equal to your number of take-offs, Preben Norholm
User currently offlinehighflyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Reply 23, posted (1 year 6 months 1 week 5 days 21 hours ago) and read 4201 times:

i use reverse thrust on every landing i perform. rarely, rarely do i use total idle reverse. i spool them up each time. no matter what, IF you had a brake failure right then and there, having the reversers already spooled and at max reverse will help more than if they were stowed. end of story.

To all those people that dont like me using reverse because they live in a noise sensitive area, too bad. you moved next to the airport, the airport didnt move next to you. Im the one slowing my airliner so it doesnt end up in your back yard, and i will decelerate as i see fit. Unless my FOM tells me otherwise, those reversers are always popped for me!

It is standard procedure at my airline per our landing profile regardless of type aircraft to deploy the reversers. from our FOM:

"The thrust reversers are intended for use during full stop landings."

"Reverse thrust reduces the airplane’s stopping distance compared to using brakes alone. Reverse thrust is most effective at high speeds."

highflyer

[Edited 2013-01-11 10:55:31]


121
User currently offlinemesaflyguy From United States of America, joined Dec 2012, 2926 posts, RR: 4
Reply 24, posted (1 year 6 months 1 week 5 days 20 hours ago) and read 4174 times:
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Quoting RussianJet (Reply 20):

LOL We're happy to assist! 
Quoting prebennorholm (Reply 22):

Don't the E-145s have visible thrust reversers? I thought they had the mini clamshell-like ones.  
(BTW, I used Thrust Reversers right this time! )

[Edited 2013-01-11 12:03:24]

[Edited 2013-01-11 12:04:10]


\________(---)________/ :) World's most beautiful aircraft: 757-200, MD-88/90, E-190, A321
25 Max Q : No, not at all, in fact that makes no sense. I have been into CPH a few times and certainly used more than idle reverse. Well said.
26 tdscanuck : Keep in mind that, on many large aircraft, autobrakes control on deceleration. As a result, they'll give almost exactly the same stopping distance wh
27 twincommander : if they arnt deployed on landing, they are most likely locked out for an MEL. most of the time at PDX, if its a landing on the long runway, its idle r
28 cornutt : At HSV, we've got RJs landing on 10,000+ ft runways, so they don't really even need to decelerate all that much. Particularly when landing on 36L -- t
29 pilotpip : Not all of them. TSA has a number of former crossair birds that do not have them.
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