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not sure and don't have time look into it right now...... the ground spoiler system doesn't require weight on wheels input.

not sure and don't have time look into it right now...... the ground spoiler system doesn't require weight on wheels input.

That's certainly interesting.

Probably - "The aft wheel ground speed is more than 80 knots" and "The radio altimeter is less than seven feet" says "we're on the ground"

Probably - "The aft wheel ground speed is more than 80 knots" and "The radio altimeter is less than seven feet" says "we're on the ground"

Granted, but on our aircraft you need a WOW input, a wheel speed input and an RA input before the ground spoilers move.

Ok, I was wrong, Ground spoilers takes WOW into account for Rejected Takeoff (but not Landing) -

The auto ground spoiler system will automatically extend the spoilers when the FCC-1/FCC-2 receives the following conditions:

- The aft wheel ground speed is more than 80 knots

- The nose gear is on the ground

- The flap position transmitter and the FADEC inputs are correct

- When two of the three throttles are in the thrust condition

- The flaps are extended more than 31.5°.

Ok, I was wrong, Ground spoilers takes WOW into account for Rejected Takeoff (but not Landing) -

The auto ground spoiler system will automatically extend the spoilers when the FCC-1/FCC-2 receives the following conditions:

- The aft wheel ground speed is more than 80 knots

- The nose gear is on the ground

- The flap position transmitter and the FADEC inputs are correct

- When two of the three throttles are in the thrust condition

- The flaps are extended more than 31.5°.

So, it actually waits for the nose gear. Even more interesting.

Not when landing.

Not when landing.

Got it, thanks.

Stupid question: An airliner (MD-11) without spoilers can bounce like a Cessna flown by a student pilot???


...except the Cessna gradually develops nosewheely shimmy while an MD-11 breaks it's wing off (along with other differences like 3 feet versus 30 feet in the bounce)

...It reminded me of that video of the A320 in Spain landing in high winds, going side to side and the nose up and down just like this MD11. But that A320 was able to climb right after the pilot pulled the yoke. Sorry, the "side stick".

I guess you mean the infamous LH landing at Hamburg
http://airdisaster.info/10/forums/viewt ... &sk=t&sd=a

If it's the one I'm thinking of, I think that was a fake.

No, David, he means the missed apoproach of a TAP-Air Portugal 320 in Lisbon.

Glenn is correct. FCC-1 and FCC-2 receive flap position, wheel speed and RA signals. The FCC will trigger spoiler deployment if all conditions are satisfied (Wheel speed >80 Knots Flaps >31 degrees, RA 7 +or-1 feet). and they are armed. if the spoilers have not extended by the time the nose gear strut compresses, the spoilers will deploy if they are armed.

No, David, he means the missed apoproach of a TAP-Air Portugal 320 in Lisbon.

Well, it's possible, but he said Spain, and Lisbon is in Portugal, or it was when I went to school. Still, some years ago there was a notorious video of a fake rough landing in an A319 or A320 in Spain in an unmarked airframe whch was some form of commercial advertising (beer, I think).

Stupid question: An airliner (MD-11) without spoilers can bounce like a Cessna flown by a student pilot???


...except the Cessna gradually develops nosewheely shimmy while an MD-11 breaks it's wing off (along with other differences like 3 feet versus 30 feet in the bounce)

HUH?

[quote="Carlos G

If it's the one I'm thinking of, I think that was a fake.[/quote]

No, David, he means the missed apoproach of a TAP-Air Portugal 320 in Lisbon.[/quote]

Yes, that's the one. Sorry I said Spain earlier. But I was close....Portugal and Spain are neighbors

What about cargo shifting to the front of the airplane during the first touchdown?

That will make the nose fall down quickly and if a go around was attempted and power applied, the nose goes up because of the "bounce" and power and surface inputs, but center of gravity too much to the front quicly makes it go down again?

If the people from FedEx are no total jerks a cargo shift is unlikely. Restraint systems normally take quite a load, which is far beyond the loads you'll have in normal flight. You need some kind of crash conditions.

First of all- condolences.

As stated above, you no-doubt know the pilots.

Now for a question.

When reading PPrune, a lot of folks claiming to be DC-10 and MD-11 pilots are saying that the DC-10 is a pleasure to fly and that an MD-11 is a handful- espcially in gusty cross winds (and blaming some of that on the MD-11 having a markely smaller horizontal stabilizer.

Would you agree that the MD-11 is harder to fly?

PIO

Interesting reading from someone ITS knows........

http://www.jetcareers.com/content/view/82/157/

Is the MD-11 harder to fly than the DC-10? I'll leave the definitive answer to those that fly the two aircraft. What follows is from my experience with the aircraft during test flights.

The MD-11 handles differently, primarily in pitch, than the DC/MD-10. The MD-11 likes a fully stabilized approach. The DC/MD-10 will tolerate a little more variance. Gusty winds complicate stabilizing an approach. The MD-11's smaller horizontal stabilizer seems to be the main reason for the difference. The smaller stabilizer is one of the aerodynamic improvements in the MD-11. To compensate, the elevators are larger (longer) and LSAS was installed.

An MD-11 pilot should have no problem with the MD-10. A DC-10 pilot will have no problem with the MD-10 but will need to learn the differences in the MD-11's quirks.

It isn't so much harder as it is different. Similar to a Cessna 152 being different than a Piper Tomahawk. Both fly equally well but require different pilot skills to keep them flying safely.

I just heard winds were extreme...gusts of around 90knots had been recorded....speculation around a strong gust of wind at the point of touchdown....resulted in extremely hard touch down, bounce and came down on its nose gear....would be interesting to hear the CVR!!!

I don't think the wind was a big factor in this one.It seems to me that at the first touchdown and at the second touchdown, the smoke from the tires is normal, without being blown away from gusty wind. Also the smoke from the fire after the crash doesn't look like there were very gusty wind conditions.

another youtube video
http://www.youtube.com/watch?v=FUhk1EInxls

doesn't really look like calm conditions to me

No, it wasn't calm.......

It's difficult to see in the videos but I have a question in my mind about the flap position.

another youtube video
http://www.youtube.com/watch?v=FUhk1EInxls

doesn't really look like calm conditions to me

I can't find where I wrote calm conditions. But I agree that it was a nice (almost blowing with the same strength during the film sequence) strong (almost) headwind. And not one gust from their right side.

A sad ending though on that video...

The winds were more or less down the runway, 300 at 20 gusting to 40 Knots. 40 knots = 72 km.

I believe wind gusts and/or wind shear may have played a roll.

The winds were more or less down the runway, 300 at 20 gusting to 40 Knots. 40 knots = 72 km.

I believe wind gusts and/or wind shear may have played a roll.

Don,

Help me here with one point: you mention wind gusting between 20 and 40 knots, right? That can (under the most negative cicumstances imaginable) make a very big difference in speed at touch-down and if so could this be the cause for an abnormal hard landing and that subsequent bumping-up after the first touch-down on (maybe only the left) MLG? Even if the pilots augmented the approach speed (Vref?) a bit for compensating the unstable wind conditions, if at t/d there is a sudden drop in wind speed of said 20 knots and if the MD-11 was heavy the subsequent bump can induce the bouncing up we saw, correct? At least in theory and this is only to be regarded as a question of a layman.

The winds were more or less down the runway, 300 at 20 gusting to 40 Knots. 40 knots = 72 km.

I believe wind gusts and/or wind shear may have played a roll.

Don,

Help me here with one point: you mention wind gusting between 20 and 40 knots, right? That can (under the most negative cicumstances imaginable) make a very big difference in speed at touch-down and if so could this be the cause for an abnormal hard landing and that subsequent bumping-up after the first touch-down on (maybe only the left) MLG? Even if the pilots augmented the approach speed (Vref?) a bit for compensating the unstable wind conditions, if at t/d there is a sudden drop in wind speed of said 20 knots and if the MD-11 was heavy the subsequent bump can induce the bouncing up we saw, correct? At least in theory and this is only to be regarded as a question of a layman.

I guess the pilots accounted for these gusts and corrected Vref upwards. As consequence, it came out pretty high.
A 20 knot horizontal gust (relative to prevailing winds), and considering a 170KIAS approach speed, causes a sudden increase to 190KIAS, which is similar to an increase in vertical load factor of 25% (1.25g). That would account for some vertical movement and a sudden bump.
We know that the MD-11 is particularly tricky at touch down.

It would be bad if it turns out that the pilots acted correctly (maybe not hero-like, but still in line with normal FedEx standards) and still crashed. It would mean that the aircraft cannot be handled safely under such circumstances by a normal crew. After all, they are no Space Shuttle pilots.