FedEx MD-11 crash at Narita

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Carlos G.
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Re: FedEx MD-11 crash at Narita

Postby Carlos G. » Wed Mar 25, 2009 12:42 pm

Thanks, Schorsch, and this is why we'd like to hear from ITS on this subject, though his silence is understandable. Emotionally in the first place, technically in second. One cannot expect him say something eventually negative about the gear he works on at FedEx, can we?

On the other hand, MD-11 in cargo version fly around the globe every day and gusty wind conditions are not that rare (see for instance the YouTube video about the other MD-11 landing at Narita under heavy wind) so this time something has to have happend which is uncommon. We have to wait, I guess.

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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Wed Mar 25, 2009 12:46 pm

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.
I highly doubt the Vref was anywhere near 170kias (unless they were in a partial flap situation). I'd say 140-145kias is a lot more like it, with a wind correction to not much more than 160kias.
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Re: FedEx MD-11 crash at Narita

Postby Schorsch » Wed Mar 25, 2009 1:09 pm

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.
I highly doubt the Vref was anywhere near 170kias (unless they were in a partial flap situation). I'd say 140-145kias is a lot more like it, with a wind correction to not much more than 160kias.
Get yourself an update of the MD-11F approach speeds!

At MLW the Vmin is close to 160KIAS already, so a 10kts addition does not appear to be too far off the mark.
The source of this Vmin recommends to add 50% of sustained wind plus full gust, but never more than 20kts.
Using that formula, we have actually have 20kts pretty quick.
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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Wed Mar 25, 2009 1:19 pm

Get yourself an update of the MD-11F approach speeds!
Go f [edited - Frankie] k yourself!
At MLW the Vmin is close to 160KIAS already, so a 10kts addition does not appear to be too far off the mark.
The source of this Vmin recommends to add 50% of sustained wind plus full gust, but never more than 20kts.
Using that formula, we have actually have 20kts pretty quick.
They were nowhere near MLW, not from Guanzhou to Narita, but thank you for playing.
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Re: FedEx MD-11 crash at Narita

Postby Ancient Mariner » Wed Mar 25, 2009 1:34 pm

Get yourself an update of the MD-11F approach speeds!
Go f [another one edited - Frankie] k yourself!
At MLW the Vmin is close to 160KIAS already, so a 10kts addition does not appear to be too far off the mark.
The source of this Vmin recommends to add 50% of sustained wind plus full gust, but never more than 20kts.
Using that formula, we have actually have 20kts pretty quick.
They were nowhere near MLW, not from Guanzhou to Narita, but thank you for playing.
Since I am thankfully not a moderator I'll go get meself some popcorn.
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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Wed Mar 25, 2009 1:39 pm

Since I am thankfully not a moderator I'll go get meself some popcorn.
Per
Good thinking.
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Re: FedEx MD-11 crash at Narita

Postby 3WE » Wed Mar 25, 2009 1:57 pm

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 think that Flyboy and I actually communicated further up in the thread. He even said I was right! Because the wind is REPORTED at 20 to 40 does not mean that plane saw EXACTLY that.

The odds of there being a random gust different from 20 to 40 is high.

The odds of a random wind gust being HUGELY different from 20 to 40 are small - but so are the odds of a plane crash. And REPORTED winds of 20 to 40 do raise the risk of a random, significantly-higher gust/shear at location near-but-not-at the anemometer.

What winds did the MD-11 actually see? I guess we'll be waiting a year for the FDR data in the final report, although I figure Aardvark2z2z2z2 might have some graphs posted -perhaps later today??? ( ;) )
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Re: FedEx MD-11 crash at Narita

Postby Dmmoore » Wed Mar 25, 2009 5:27 pm

I saw the earlier posts by you (3WE) and Flyboy. I agree the wind speeds reported on the METAR's and actual wind speeds encountered by the aircraft on the runway could be different. My point was the difference between the speeds reported in the press were given in kilometers per hour and in one case meters per second. I noticed some posters were confusing knots with kilometers.

The data needed to determine cause is a long way off. As usual, it will turn out to be several items combined, not one specific thing. Wind is very likely to be one of the items.

A side note to a comment Flyboy made to Schorsch. It's almost impossible for the aircraft to be anywhere near MTOGW at departure (for the non aviation type, max zero fuel weight is the difference between MGW (Max Gross Weight) and MLW (Max Landing Weight). The fuel burn between the takeoff point and destination would not be enough to allow a MTOGW departure and met the requirements for MLW at NRT. That said, without knowing the landing weight, all we can do is guess at VREF. In my opinion, 160 - 170 Kts is close the upper limit, 130 - 140 Kts is close to the lower limit.
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Re: FedEx MD-11 crash at Narita

Postby AndyToop » Thu Mar 26, 2009 11:54 am

for the non aviation type, max zero fuel weight is the difference between MGW (Max Gross Weight) and MLW (Max Landing Weight).
as opposed to for the aviation type where that statement would be pure bullshit? :shock:

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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Thu Mar 26, 2009 12:30 pm

(for the non aviation type, max zero fuel weight is the difference between MGW (Max Gross Weight) and MLW (Max Landing Weight).
Really, Don, stick to wrenching questions. Between the above and the malarkey you've posted on the other site, you sound like you wasted these past four decades.
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Re: FedEx MD-11 crash at Narita

Postby Ancient Mariner » Thu Mar 26, 2009 12:57 pm

Since I am thankfully not a moderator I'll go get meself some popcorn.
Per
Good thinking.
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Re: FedEx MD-11 crash at Narita

Postby GlennAB1 » Thu Mar 26, 2009 3:19 pm

Flyboy; how about you just correcting peoples mistakes without the insults?
you still have to find a crew willing to fly this "barely airworthy" heap
no such thing as "barely airworthy" it's either Airworthy or Not
100% incorrect Ever hear of Ferry Permit? issued for Non airworthy aircraft
LOL

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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Thu Mar 26, 2009 3:58 pm

Flyboy; how about you just correcting peoples mistakes without the insults?
What fun would that be? Especially with Don who has a tendency to go out of his way to talk about things he has no idea about.
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Re: FedEx MD-11 crash at Narita

Postby Dmmoore » Thu Mar 26, 2009 4:52 pm

Yes, I didn't expound enough.

"The Zero Fuel Weight (ZFW) of an airplane is the total weight of the airplane and all its contents, minus the total weight of the fuel on board.

For example, if an airplane is flying at a weight of 5,000 lb and the weight of fuel on board is 500 lb, the Zero Fuel Weight is 4,500 lb. Some time later, after 100 lb of fuel has been consumed by the engines, the total weight of the airplane is 4,900 lb and the weight of fuel is 400 lb. The Zero Fuel Weight is still 4,500 lb.

Note that, as a flight progresses and fuel is consumed, the total weight of the airplane reduces, but the Zero Fuel Weight remains constant (unless some part of the load, such as parachutists or stores, is jettisoned in flight).

For many types of airplane, the airworthiness limitations include a Maximum Zero Fuel Weight."

Some aircraft do not have a published MZFW. All powered aircraft require fuel, therefore the weight of the aircraft minus fuel is the ZFW.

When an airplane is being loaded with crew, passengers, baggage and freight the total weight must not exceed the aircraft's published Zero Fuel Weight.

When an airplane is being loaded with fuel it must not maximum permissible takeoff weight. The planned fuel burn must place the aircraft at or below the max landing weight.

MZFW : The maximum weight of an aircraft prior to fuel being loaded.

ZFW + FOB = TOW

For any aircraft with a defined Maximum Zero Fuel Weight, the maximum payload can be calculated as the MZFW minus the OEW (Operational Empty Weight)

MaxPayload = MZFW − OEW.
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Re: FedEx MD-11 crash at Narita

Postby Schorsch » Thu Mar 26, 2009 5:35 pm

Flyboy; how about you just correcting peoples mistakes without the insults?
How should he, he doesn't know himself.
As pilot he is used to look up things in books which are handed to him, and not to look into anything that was not given to him, as it might not be certified, and consequently dangerous. That is a good firewall against any gain in knowledge.
You can spend you're entire day with the question "Is that from a certified source?" in aviation-related forum and pretend to some less gifted people you know it better.
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Re: FedEx MD-11 crash at Narita

Postby PurduePilot » Thu Mar 26, 2009 6:16 pm

Yes, I didn't expound enough.

"The Zero Fuel Weight (ZFW) of an airplane is the total weight of the airplane and all its contents, minus the total weight of the fuel on board.

For example, if an airplane is flying at a weight of 5,000 lb and the weight of fuel on board is 500 lb, the Zero Fuel Weight is 4,500 lb. Some time later, after 100 lb of fuel has been consumed by the engines, the total weight of the airplane is 4,900 lb and the weight of fuel is 400 lb. The Zero Fuel Weight is still 4,500 lb.

Note that, as a flight progresses and fuel is consumed, the total weight of the airplane reduces, but the Zero Fuel Weight remains constant (unless some part of the load, such as parachutists or stores, is jettisoned in flight).

For many types of airplane, the airworthiness limitations include a Maximum Zero Fuel Weight."

Some aircraft do not have a published MZFW. All powered aircraft require fuel, therefore the weight of the aircraft minus fuel is the ZFW.

When an airplane is being loaded with crew, passengers, baggage and freight the total weight must not exceed the aircraft's published Zero Fuel Weight.

When an airplane is being loaded with fuel it must not maximum permissible takeoff weight. The planned fuel burn must place the aircraft at or below the max landing weight.

MZFW : The maximum weight of an aircraft prior to fuel being loaded.

ZFW + FOB = TOW

For any aircraft with a defined Maximum Zero Fuel Weight, the maximum payload can be calculated as the MZFW minus the OEW (Operational Empty Weight)

MaxPayload = MZFW − OEW.
Probably a little nit-picky, but where does engine oil fit in?

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Re: FedEx MD-11 crash at Narita

Postby AndyToop » Thu Mar 26, 2009 6:30 pm

Yes, I didn't expound enough.

"The Zero Fuel Weight (ZFW) of an airplane is the total weight of the airplane and all its contents, minus the total weight of the fuel on board.

For example, if an airplane is flying at a weight of 5,000 lb and the weight of fuel on board is 500 lb, the Zero Fuel Weight is 4,500 lb. Some time later, after 100 lb of fuel has been consumed by the engines, the total weight of the airplane is 4,900 lb and the weight of fuel is 400 lb. The Zero Fuel Weight is still 4,500 lb.

Note that, as a flight progresses and fuel is consumed, the total weight of the airplane reduces, but the Zero Fuel Weight remains constant (unless some part of the load, such as parachutists or stores, is jettisoned in flight).

For many types of airplane, the airworthiness limitations include a Maximum Zero Fuel Weight."

Some aircraft do not have a published MZFW. All powered aircraft require fuel, therefore the weight of the aircraft minus fuel is the ZFW.

When an airplane is being loaded with crew, passengers, baggage and freight the total weight must not exceed the aircraft's published Zero Fuel Weight.

When an airplane is being loaded with fuel it must not maximum permissible takeoff weight. The planned fuel burn must place the aircraft at or below the max landing weight.

MZFW : The maximum weight of an aircraft prior to fuel being loaded.

ZFW + FOB = TOW

For any aircraft with a defined Maximum Zero Fuel Weight, the maximum payload can be calculated as the MZFW minus the OEW (Operational Empty Weight)

MaxPayload = MZFW − OEW.
Don,

Really sometimes you should just say "My Bad" and let it go :)

Hmmm Lets see so if we take the figures direct from the boeing website for the MD11 Frieghter variant - seems appropriate for the thread

MZFW 451300lb - OEW 248567lb
we should get a max payload of 202733lb
but its only 163004 - Don - where has the other 40,000lb of payload gone! Thats 20% lower than it should be.

To help you drum up some other formulae here are the rest of the numbers for you.
MTOW 602500
MZFW 451300
MLW 471500
OEW 248567
Max Payload 163004

However to let FlyBoy and Schorsch get back to their argument:-

with an OEW of 248,567lb and a max payload of 163,004lb there would need to be at least 60,000lb of fuel left on board to be around MLW which would mean either they were maxed out on cargo and carried a lot of extra fuel (possible - I have no idea if they would tanker fuel between China and Japan - could have been fuelled enough for a return trip, but its certainly not a long haul flight) or they were no where near MLW

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Re: FedEx MD-11 crash at Narita

Postby ZeroAltitude » Thu Mar 26, 2009 6:54 pm

Probably a little nit-picky, but where does engine oil fit in?
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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Thu Mar 26, 2009 9:44 pm

Yes, I didn't expound enough.
Didn't expound enough? How about posted garbage yet again? According to your brilliant formula the MZFW of the CRJ, for instance, is only 6,000lbs. I know for a fact it's 44,000lbs.

Expounding has nothing to do with it.
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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Thu Mar 26, 2009 9:46 pm

As pilot he is used to look up things in books which are handed to him...
You say it like it's a bad thing. Where would rather me get my weight numbers, the manuals issued by the airline or some internet dumbass?
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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Thu Mar 26, 2009 9:47 pm


Don,

Really sometimes you should just say "My Bad" and let it go :)
Yes, he should.
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Re: FedEx MD-11 crash at Narita

Postby flyboy2548m » Thu Mar 26, 2009 11:42 pm

BTW, the current MTOW of the MD-11 is 630,500lb.
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Re: FedEx MD-11 crash at Narita

Postby Peminu » Fri Mar 27, 2009 6:09 am

BTW, the current MTOW of the MD-11 is 630,500lb.
A question to all pilots and aviation experts here (and I am not discarding your answer Flyboy, just curious):

Do you correct this MTOW according to the altitude above sea level and lenght of the takeoff runway? Or do you only mind about the rotation speed?

In other words: do you have a MTOW for different runways? (According to lenght and altitude above sea level?)
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Re: FedEx MD-11 crash at Narita

Postby AndyToop » Fri Mar 27, 2009 10:52 am

BTW, the current MTOW of the MD-11 is 630,500lb.
is that the MMTOW :D

I know the ER had that as standard, but it was an option on the freighter.
That said the freighter also the option to have the MLW upped by 20,000lb as well. Neither option ups the MZFW or MP so if it was fully tricked out it would have needed 80,000lb of fuel to be close to MLW. It's a couple of thousand mile trip, so that would be what - somewhere in the region of 50-60k lb of fuel at max payload?

So if they were fueled for there and back, then they could potentially have been close to MLW.

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Re: FedEx MD-11 crash at Narita

Postby Schorsch » Fri Mar 27, 2009 10:57 am

As pilot he is used to look up things in books which are handed to him...
You say it like it's a bad thing. Where would rather me get my weight numbers, the manuals issued by the airline or some internet dumbass?
I will certainly come back to you when I need numbers on the CRJ.
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