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Air Traffic Monitoring => Listener Forum => Topic started by: Аэрофлот Jr. on February 24, 2009, 10:31:49 PM

Title: Question about Airbus A380.
Post by: Аэрофлот Jr. on February 24, 2009, 10:31:49 PM
Anyone know why A380 is able to reverse thrust only on engine number 2 and 3 ? (i never saw reverse thrust deployed on engine 1 and 4,) are the reverse thrust avail on all engine but just using #2,3 reverses or is there any reason not using reverse on #1,4 ?
Title: Re: Question about Airbus A380.
Post by: dave on February 24, 2009, 10:38:52 PM
1) They don't need it on all four.  Most of its stopping power is in the brake system.

2) It has only its inner engines operate with reverse thrust to protect the outer engines from ingesting debris (since the outer engines are close to the edge of the runway at most airports).
Title: Re: Question about Airbus A380.
Post by: Аэрофлот Jr. on February 24, 2009, 10:51:11 PM
Ohh, very clear now =]

Thanks Dave .
Title: Re: Question about Airbus A380.
Post by: strangr on February 25, 2009, 06:59:16 AM
and was it true also that they were unable to place them on the outside because of grass and mud being kicked onto the runway.

they actually wanted no rev thrusters at all on the a380 but had to because the FAA wanted them
Title: Re: Question about Airbus A380.
Post by: Аэрофлот Jr. on February 25, 2009, 07:14:15 AM

they actually wanted no rev thrusters at all on the a380 but had to because the FAA wanted them

are they even possible for slow down with just the bracking system without any reverse ?
Title: Re: Question about Airbus A380.
Post by: cessna157 on February 25, 2009, 08:37:56 AM
Yes, reverse thrust is just an added bonus.  Isn't required at all.  Some airplanes don't even have them (Bae146/Avro, Diamond Jet, CitationJets [had to put that in for you Jason] to name a few).  Sometimes 1 or both reversers can be deferred.  And some airlines/airports have agreements that only idle reverse thrust will be used (LHR if I remember requires it?).

On some performance calculations in the books for airplanes, reverse thrust isn't included.  So it is just a greater stopping power.  Depending on the airplane, outside conditions, runway conditions, and weight, reverse thrust sometimes doesn't do a whole lot for you.
Title: Re: Question about Airbus A380.
Post by: hakan737 on February 25, 2009, 10:14:51 AM
A380 wings are too large.so many airports runways are not quite enough, almost A380 engines limitations. A380 engine fans are too big.E1 and E4 are too out of the wings and this is possible FOD causing while reversing. Two engine ise enough with uncountable tyres! :)
Title: Re: Question about Airbus A380.
Post by: sykocus on February 25, 2009, 10:17:20 AM
Yes, reverse thrust is just an added bonus.  Isn't required at all.  Some airplanes don't even have them (Bae146/Avro, Diamond Jet, CitationJets [had to put that in for you Jason] to name a few).  Sometimes 1 or both reversers can be deferred.  And some airlines/airports have agreements that only idle reverse thrust will be used (LHR if I remember requires it?).


They aren't required to stop the plane, but from what I've read the FAA required them them to certify the plane.
Title: Re: Question about Airbus A380.
Post by: dgpilot on February 25, 2009, 02:17:28 PM
Some pilots, flying heavies like 747 and 777 don't even use them when landing at major airports with sufficient runway length
Title: Re: Question about Airbus A380.
Post by: Аэрофлот Jr. on February 25, 2009, 03:27:26 PM
Very nice informations guys (: thanks .
Title: Re: Question about Airbus A380.
Post by: Unbeliever on February 25, 2009, 10:03:11 PM

They aren't required to stop the plane, but from what I've read the FAA required them them to certify the plane.

Citation please. 14CFR Parts 25, 26, or 29 don't have any mention that reversers are required for Transport category aircraft.  In fact, for a dry runway, 25.109 (f)(1) says that reverse thrust, if available, shall not be used to determine stop-start distances.

--Carlos V.
Title: Re: Question about Airbus A380.
Post by: sykocus on February 26, 2009, 05:48:53 AM
I couldn't find reliable source. It seems to me I first heard it watching a tv show on the development of the a380. There are of course references to it in wiki (http://en.wikipedia.org/wiki/Airbus_A380#Systems), yahoo answers (http://answers.yahoo.com/question/index;_ylt=Am7B4S2r7VceXdxLaCaw1LgjzKIX;_ylv=3?qid=20090109014456AA8ZW2f) and  google (http://www.google.com/search?q=a380+thrust+reversers&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a), but like I said i couldn't find anything credible by its self. When the FAA certifies a new type I don't think requirement is already found spelled out in the FARs. The 787 is being designed with bleedless engines and many things like air condition and deicing will be handled by electrical systems instead of bleed air from the engines. I'm sure the FAA will have new requirements for boeing that aren't currently found in the FARs before certifying the plane for use.
Title: Re: Question about Airbus A380.
Post by: Hollis on February 26, 2009, 07:12:56 PM
Reverse thrust can never be used as a standard to determine landing distance performance. Simple reason - reliability. (You can't reverse a dead engine!).