Originally Posted by dckozak
(Post 1754436)
We do not, but that is an interesting point I'll raise with our LCA's or at the school house when I see them. From my experience, the CG is always fairly far forward, no doubt a function of carrying normal freight rather than the self loading type you guys fly :D
Being a former KC135 guy, I was very much aware of the CG, all the time. When I got on the MD11, I asked why there were no limits for landing, and 'what if' it got too far aft? "That'll never happen..." was about all they ever said, then they just kept crash landing them...:rolleyes: Did they at least fix the fuel management computer so it will run all the tail fuel fwd regardless of altitude? I can't recall the exact number but I think around 17,000' all fuel shifting would stop, so if you came down from say 350, very quickly, you would go through 17 (or was it 19?) and there would still be fuel in the tail...which you couldn't move forward, and you were stuck with an aft CG for landing. |
What a setup that was--took some real engineering w/o any practical experience to design that! :confused:
GF |
Originally Posted by galaxy flyer
(Post 1754822)
What a setup that was--took some real engineering w/o any practical experience to design that! :confused:
GF The problem was if you went off schedule...:rolleyes::eek: |
Originally Posted by Timbo
(Post 1754803)
What happened in most of the hard landings was, they were on short hops, then came down from altitude very quickly so there was fuel trapped in the horizontal stabilizer, which gave them an aft CG, but they weren't paying attention to the CG, even though it is indicated right there on the EICAS.
Being a former KC135 guy, I was very much aware of the CG, all the time. When I got on the MD11, I asked why there were no limits for landing, and 'what if' it got too far aft? "That'll never happen..." was about all they ever said, then they just kept crash landing them...:rolleyes: Did they at least fix the fuel management computer so it will run all the tail fuel fwd regardless of altitude? I can't recall the exact number but I think around 17,000' all fuel shifting would stop, so if you came down from say 350, very quickly, you would go through 17 (or was it 19?) and there would still be fuel in the tail...which you couldn't move forward, and you were stuck with an aft CG for landing. There is no TFM unless your fuel system is able to run in auto. In manual mode, no TFM. If auto fails in flight and you revert to manual, all TFM stops and the fuel transfers forward. In order to activate TFM, you have to have more than 60K of FOB at the end of refueling. It stops any further aft transfer at 51K FOB. So, short hops aren't a factor unless you're tankering gas. The tail fuel is sent forward when any one of the 3 main tanks hits 11.5K to keep all three tanks at that level until tail is dry (so, roughly 35K+ 13K of tail fuel = 48K FOB it begins) No matter what, ALL tail fuel begins to get transferred forward on descent passing about 27,000 feet. The only way it stops transferring forward and becomes "trapped" in the tail is below 18,000 and dirty (any one of slats, flaps, gear). In practice, the only time getting fuel trapped on descent might be an issue would be an air turn back or tankering scenario. Even then, you'd probably have to put the slats out VERY early to trap the gas. I've gone through 27,000 with a full tail tank just starting to transfer forward and it's empty by the time we get below 10K. IMO, this is a great airplane. I've flown three 2-engine Boeings and the A319/320. The systems on the MD-11 are head and shoulders above those other jets. Part of that is just due to the redundancy available from a third engine. But the system interface, displays and operation are truly superior as well. I also enjoy the way it flies. You can click everything off and fly it just like any airplane. I flew it for two years before I heard anyone tell me how hard it was to land. Yeah, a pilot probably can't get away with some of the ham-fist stuff that passes muster on a 777 or some other Boeing. So, you bring your A-game (like everyone should anyway). If that's too much to ask, then I guess the 777 is the obvious choice. As Dirty Harry said: "A man's got to know his limitations". ;) But, really it's all the old basics: Use power properly on final and in the flare and make adjustments based on your landing weight, land on centerline, de-crabbed, at the correct pitch and don't fix a sinker with pitch. Those rules have pretty much worked with any jet I've flown (except F-15s and T-38s didn't de-crab). |
Like I said earlier, I flew it for 4 years and never had a bad landing.
BUT, I never trusted it to do what I wanted it to! Whereas with the 757/767/777, I can pretty much sleep through every landing, even with a big crosswind, and it's going to be a grease job. Much easier to fly the Boeings! They are all much less automated than the MD11, but I like it that way. I don't like any airplane that thinks it knows what I want to do! In fact, the only thing I don't like about the 777 is, it puts in nose up trim for you when you bank it into a turn! I want to do that! I don't want it doing it for me! It just fks up my SA. I guess since Boeing and Airbus are selling their airplanes to the third world, they have to make them as easy to fly as possible, by guys with almost no flying time. Look at the Asiana crash in SFO. Can you imagine if they were in a MD11 and got that low and slow?? You think there would have been any survivors?? From the MD11 article, in case you skimmed over it and missed the important stuff: Yet, for all its romantic cachet and sleek lines, the MD-11 was a commercial flop that sold only 200 units over a short production run from 1988 to 2000, and was haunted by a poor safety record. Conceived by McDonnell Douglas as a bigger successor to the DC-10, which was also retired this year, it was plagued by issues including higher fuel burn than anticipated and poor reliability in its initial years, which cost airlines money. Pilots loved the roomy cockpit with large digital displays, but were less enamored of the plane's nervous temperament. The MD-11 was famously hard to land, and especially balky when the wind came from its side. Landing crashes accounted for five of the nine MD-11 accidents. According to data published by Boeing and updated through 2013, it had had 3.62 accidents with hull losses per million departures, far more than contemporary large jets. The MD-11 was almost four times more likely to crash, statistically, than the Boeing 747 series 400. |
777 puts nose up trim in a turn? That seems annoying. Is there no way to disable that?
|
Originally Posted by Yoda2
(Post 1754909)
777 puts nose up trim in a turn? That seems annoying. Is there no way to disable that?
It only takes a few legs to get used to it, but when I first got on it, I found it a pita, as I would instinctively add back pressure in the turn. Now, after 8 years of flying it, I'm pretty much used to it. Oh, and if you lose an engine, it adds the correct rudder for you too. It does so much for you, it will make you stupid. Ask the Asiana guys. God forbid I ever have to go back and fly a real airplane again! :eek: |
Originally Posted by Timbo
(Post 1754913)
Yes, it does, and no, you cannot disable it
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Originally Posted by Timbo
(Post 1754890)
Pilots loved the roomy cockpit with large digital displays, but were less enamored of the plane's nervous temperament. The MD-11 was famously hard to land, and especially balky when the wind came from its side.
|
Actually, if they'd been flying an MD11, it would have saved them. Low speed protection in the MD adds throttle at Vmin - even in FLCH mode. Seen it happen many a time when the newbies pull up early on a level-off. B777 - not so much.
Originally Posted by Timbo
(Post 1754890)
Look at the Asiana crash in SFO. Can you imagine if they were in a MD11 and got that low and slow?? You think there would have been any survivors?? |
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