reversers vs brakes

[avionneta]

hello,
I'm looking for info about the cost of using reversers on engine maintenance versus the cost of the brakes wear when you don't use them ?

[Sean Dell]

I think if you spoke to Mr Airbus - he would be happy just with brakes. Indeed I am led to believe that the A380 was originally designed with no reversers - it was just the FAA that insisted on inboard (?) reversers being present to allow for certification.

HTH

[Canuckbirdstrike]

Simple question, complex answer. The cost issue is dependent on whether you are using steel or carbon brakes and how your brake and engine maintenance costs are attributed (part of lease cost, per cycle, hourly etc.)

Overall from a cost perspective with carbon brakes it is more cost efective to use more brakes and less reverse. The decision must be adjusted for each landing to cater to weight, landing distance available, runway condition and turnaround time.

[varigflier]

Doesn't the FARs say to use the reversers whenever possible as soon as touchdown to decrease the landing distance? I see people using just brakes all of the time....

[lomapaseo]

If you factor in the cost of ownership, including maintenance, it's far cheaper to not even own a reverser and its maintenance. Of course then you are going to have to rely on both the pilots and the brakes not to overextend the safety margins presumed in each legal landing.

I like an occasional backup like a chute, or an arrestor system and forget the reversers

[yrvld]

sorry, not trying to be sarcastic, but are you pilots or economists?

[Canuckbirdstrike]

Small clarification on my earlier post. I do not advocate or support using NO reverse. The best option is to use IDLE reverse when operationally safe and feasible. This is the best balance of cost vs. options for safety. This allows the selection of more reverse if required for unforeseen circumstances without having to wait for them to deply.

[john_tullamarine]

Oh dear ... gone are the days when one would rip in a fistfull of reverse on touchdown and savour the engines' sweet song on the landing roll ...

MFS has queried a comment I made here (and now have deleted) regarding certification aspects of reverse thrust .. as I can't lay my hand on the regulatory derivation, it is best that the comment be removed to avoid confusion. It may be that my memory has placed the requirement in the wrong jurisdiction ...

[G-ALAN]

On a wet or standing water/contaminated runway wouldn't reverse reduce the landing roll considerably?

[firebird_uk]

Here in my ATPL Aircraft General Knowledge manual it says "On a jet most of the retardation on the landing or rejected take-off comes from the brakes rather than the thrust reversers."

And if that's what the JAA say I guess it must be true.

But what do I know, I'm taking an ATPL(H) and having to study 737 landing gear systems! You know it makes sense.

[Brian Abraham]

but are you pilots or economists?

Pilots, pilots?????? No such thing these days, systems managers please!!!! Do keep up.

[ERJFO]

Doesn't the FARs say to use the reversers whenever possible as soon as touchdown to decrease the landing distance? I see people using just brakes all of the time....

No. For an FAA governed airline to even fly to an airport the airplane must be able to stop on 60% of the available runway with breaks and spoilers only.

Most airlines now are changing their SOP from using full reversers on landing to using idle reversers (deployed but not spooled) and breaking unless more stopping power is needed at the descretion of the crew.

[tom775257]

It is interesting, my airline asks us to use max reverse every landing when no noise abatement is in force, and use minimum brakes. At our base airfield which has a very long runway, means I rarely ever touch the brakes above 70kts or so when I bring the reverse back to idle.

I personally don't worry about the economics of brakes vs. reverse, I do what the company want when performance and airmanship permits. Our aircraft are leased, so perhaps this means engine wear isn't considered as much? Who knows, I like it, I get to make lots of noise

We have very new 320s, carbon brakes.

Tom.

[Penworth]

Conversely, my airline (737/757) tells us to use idle reverse only with most of the stopping coming from the brakes. This is undoubtedly what they've worked out is the most economical technique for our aircraft. And as canuckbirdstrike says, this has the benefit of allowing more reverse thrust if required. I may be wrong but I seem to remember reading that brake life also increases with a steady higher autobrake selection (2 or 3) as opposed to minimum autobrake. This would be another argument for the way its done in my airline.

PW

[GlueBall]

QF1, B747-438 overrun at BKK 23 Sep 1999 demonstrated that QF's "no reverse" procedure was flawed. The accident report also had stated the manufacturer's recommendation to use reverse thrust for all landings.

[p1fel]

Brake Wear Study

I remember reading a detailed study carried out by Lufthansa for their fleet of Airbus and Boeing aircraft, re costs for brake wear/replacement, fuel costs, engine wear, blocker door wear, etc.
The conclusion was for all fleets use 70% N1 Reverse and dependant on fleet, either Medium or Auto Brake 2 setting.
I caution this may well be out of date at todays costings as this study was carried out in the early 90's.

[BelArgUSA]

I personally require (classroom, simulator or line) the deployment of reversers (even if only at idle) to cancel the "residual thrust" of engines. On the 747s, we use minimum brakes on dry runways, and medium brakes on wet runways. Landing without reversers deployed is against our SOPs. They stay deployed (at idle) until about to start the turnoff. We also recommend to use full length of the concrete... no hurry to get these "high speed" turnoffs, we much prefer to add 1/10th of flight pay for taxi-in time.
xxx
Old military habit... I still do aerodynamic braking as well. My privilege, thanks to my position and seniority... I hear some of you objecting "you will hit the tail, one day"... Well, in about 22,500 hrs of flying, including stretched DC-8s, I never scraped the tail, and with only a few months left in my career, unlikely I will do... knock on wood.
xxx
In 90% of my landings (all are on 10,000+ feet long runways), I guarantee that I turn off at the end of the runway without use of brakes, as I disconnect autobrakes, after satisfactory touchdown on dry runways. Brakes remain cold, put your hands on them, if you do not believe me.
xxx
And as far as "medium breaks" are concerned, they are 15 minutes long for classroom/simulator sessions.
xxx

Happy contrails

[pakeha-boy]

Quote Brian.....Pilots, pilots?????? No such thing these days, systems managers please!!!! Do keep up.

well said mate and absolutely true......flew the F-28 for several years,no reverse,just brakes.....worked just fine.....fly the 321 now and have reversers,and poor brakes.....works just fine....

.reallly dont care about the cost....you need them to take-off and land....their costs?????? ...it called the costs of doing buisness!!!

[avionneta]

what is generally accepted for 747 is not for medium weight aircraft, I mean, to let go the aircraft to the end or the first after the speed is very slow. you exit where you want anyway but minimum runway occupancy time must probably wait for medium jets to use there brake

[BelArgUSA]

¡Basta, Che!
xxx
I am certain you love to follow the 747s "very close"... dont you...?
Try it 30 seconds behind... and remember, at LEMD, I do "1 dot" above glide slope.
Feliz acercamiento para vós...
xxx

Happy contrails