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View Full Version : MD-11 similar to Airbus?


FL999
7th Dec 2009, 04:43
Hi guys. Ive been reading a lot about the MD-11 and ive seen a couple of pictures and I couldnt help but compare the plane to Airbus' planes. The LSAS seems to function like Airbus' Fly-byWire, its equipped with stall protection and Auto-trim, the MCDU interfaces are nearly identical, the systems layout and all lights-off policy for the overhead panel are somehow similar..!...what happened there? Or am I just seeing things?:confused:

411A
7th Dec 2009, 05:33
The latter category...from what little I know about the MD-11.
In fact, the MD-11 may well be closer in design to the L1011...than any sort of FBW Airbus.
For example, the L1011 has a 'lights out' overhead panel as well.
It also has a stability augmentation system.
Some models have active ailerons for gust alleviation/wing bending relief.

poina
7th Dec 2009, 08:08
MD says the the MD-11 has "relaxed stability", it got that assignment because after flight testing they found it was way off it's range predictions, only way to fix it without redesigning its wing was to put in a wet tail to assure an aft cg to reduce fuel burn. LSAS was/is designed to compensate for pitch excursions either in auto or manual flight. Only full FBW is the auto throttle system.

pullup hard
7th Dec 2009, 09:28
999- having flown on both for several years, I disagree with your statement of having similar systems.
Interfaces though, do look the same, you will always find system operation on overhead panel and a couple of MCDUs on any modern plane.
Main difference of the two: MD11 does automatic system reconfigurations (as it is derived from the 3 men operated DC10, so the system architecture took over the job of man no.3)-in this particular field it is more advanced than Airbus (320-330-340). Everything else is 70ies technology.
Stall protection: Stick pusher has got nothing to do with FBW
Autothrottle: FADEC....ok, you can call that computer driven thrust, but FBW?
LSAS is a stability system that was introduced to make it more flyable, as it is a very unstable aircraft (long fuselage, small elevator, critical CG). To fly manually however, LSAS was a pain and always interfering with your inputs.t was, if I remember correctly, mainly gyro- driven. FMS capability was a lot less than today's airbus.
I could go on with the list- bottom line is: 2 very different A/C to operate and very different to handle.
Hope that helps.
Cheers, puh

FL999
7th Dec 2009, 10:37
I see. Thanks for the info! As i only have limited knowledge of the Airbus systems it only looked the same. I guess theyre 2 completely differnt planes after all. Thought as much! Cheers guys!