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How Do You Suppose This Happened?

Posted: Mon May 31, 2004 3:26 am
by MD11LuxuryLinr

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Photo © Erwin



The number 2 pic of the day. Look at the nose gear angle and the rudder. Did the pilot not set the tiller to the straight forward position or was there some sort of malfunction?

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 4:08 am
by dl757md
Just a guess but it appears that number 4 engine is not running. The pilot has full left rudder and full left nose steering with the tiller to offset the resulting asymmetric thrust. If he didn't have asymmetric thrust that plane wouldn't be going straight down the runway with full left nose steering and full left rudder. Looks as though somebody thought they were flying a three holer when they were starting engines. OOOPS!

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 8:40 am
by VC-10
There is more to it than that. On EICAS he would have had messages for

1) Eng 4 Low Oil Press

2) Eng 4 IDG Inop

3) Eng 4 Hyd EDP Low Press

4) Bleed 4 Off

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 9:03 am
by dl757md
Also there would be no N1, N2, EGT, oil press, oil temp, FF, and VIB indications either. That doesn't explain the FACT that the #4 engine is not turning in this picture. The following is from ERWIN972 the photog who took the pic.

"Besides the full left rudder, also note engine #4, it seems not operative. With a shutterspeed of 1/400, f/2.8 it expect it to have blurred like the other fanblades did."

The #4 fan would have rotated several times in 1/400th of a sec. making the rotation marks on the spinner blurred as on the other three spinners.

What other conclusion can you make? The crew simply made a gross error in preflight and takeoff procedures! They then covered it up as best as they could.

Please see https://www.airliners.net/discussions/aviation_photography/read.main/134275/ reply 7

Pilots make mistakes like the rest of us. Let's just be glad for this crew and those in the area that they were able to recover from a potentially deadly situation.

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 9:13 am
by EMBQA
After reading what the photographer said....my best guess....The crew pushed it to full throttle before they where ready to go. The nose wheel was not centered, and as many above have said, it looks like the #4 engine is not yet on line. OOps..!!

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 9:15 am
by NZ767
Maybe the photograph was simply taken a few minutes after the incident (there would still be a lot of smoke around) after the number 4 was switched off but before the other three were.

Adding to the last two posts, the takeoff config alarm would've been deafening wouldn't it?  Smile


RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 9:16 am
by VC-10
I realise the the engine parameters would all be zero but the point I was making was that there would be warning messages on the main EICAS Screen. In addition in my experience of taxiing 747's the a/c would have drifted to the right during the taxi-out.

I am not disagreeing with what you say, but it is very worrying that there are pilots out there who would appear not to notice something like that.

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 9:17 am
by dl757md
VC-10

I'm not sure. Would he have gotten those EICAS MSGS had he never started #4 or only in the event of a shutdown?

I must admit I'm not familiar with the 747, but have worked 37/57/67 and have never gotten these EICAS MSGS when doing a single engine MX run.

Dl757md


RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 9:36 am
by Jofa
What makes people say that engine 4 is not running? Is it because the center of the engine looks different? Well, it IS different, just look at other pics of the aircraft and notice that engine number one has a silver center, number two is black, number three is silver again and number four is a spiral.

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Photo © Alexander Jonsson



[Edited 2004-05-31 02:37:19]

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 9:57 am
by dl757md
Jofa

The silver spinners on engines 1 and 3 appear silver because they have a white rotation indicator painted on them. When the engine is running the indicator appears blurred and when the engine isn't running it appears as a spiral as on the #4 engine of the incident plane. These rotation indicators provide visual indication of engine operation status ie. running-not running for ground crews. It's not always easy to tell from the engine noise as the noise of other engines on the aircraft or in the area can be confusing. The number 2 engine on the above AC either doesn't have an indicator or it has worn off. I've seen both situations. Rest assured the fact that the rotation indicator is clear, not blurred, on the #4 eng of the incident AC means it wasn't operating at the time the pic was taken.

Have included a pic of the incident AC clearly showing how #4 eng appears when it is running.

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Photo © Johan Kellerman




Dl757md

[Edited 2004-05-31 03:04:00]

[Edited 2004-05-31 03:06:52]

[Edited 2004-05-31 03:19:28]

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 10:17 am
by PhilSquares
I really have to say something.

All this speculation about pilots attempting to take off with the #4 engine not started, or as one poster said, trying to take off like a three holer.

What a crock!!!!!

1) None of the posters were there.
2) Did you ever consider the possibility of an engine failure at low speed?
On the -400 the worst situation for an engine failure is at low speed when the rudder isn't effective. Boeing recommends the tiller not be used on the T/O roll. Therefore, if you have an engine failure you have to get the engines back to idle asap, otherwise you will be off the runway in no time flat. The nose gear only gives =/- 7 degrees of steering, whereas the tiller gives you +/-70 degrees. Boeings big worry is overcorrecting on the tiller at ever increasing speeds.
3) There is an EICAS message of "engine shutdown", the last thing you do, prior to engine start is check the EICAS messages. The 4 engine shutdown messages are all you should see. Please give the flight crew some credit.

Just as an aside, the aircraft is actually owned and operated by Atlas Air.

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 10:23 am
by dl757md
Philsquares

Why would the crew have taken the plane immediately after this incident if there was an engine failure or any other system failure for that matter?

Dl757md

[Edited 2004-05-31 03:31:31]

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 10:40 am
by Jofa
Dl757md
I'm glad you choose that image to illustrate your point, cus i have taken it. The exif data on the image says 1/750s, thats more than enough to get a very clear spiral/spinner on an aircraft landing or on it's takeoff-roll.

[Edited 2004-05-31 03:50:38]

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 10:43 am
by AWspicious
Perhaps, they were in the process of shutting down the engines... Starting with #4... ?

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 10:49 am
by Jofa
I still don't get why people think the engine is beeing shut down or already shut down? It's center is diffrent from the others, ok? The photographer stated in another thread that the picture was taken with a shutterspeed of 1/400, i just looked at some of my images and had crystal clear spirals/spinners at 1/250. Give it a rest.

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 11:03 am
by dl757md
Jofa

I'm glad you choose that image to illustrate your point, cus i have taken it. The exif data on the image says 1/750s, thats more than enough to get a very clear spiral/spinner on a landing aircraft.

How do you figure 1/750s is quick enough to show a clear spiral on a landing engine.?
I'm not sure what engines are on this plane so lets take the GE CF6-80C2F for example. 100%N1 fan speed is 3450rpm. Ground idle is 24%N1 or 828rpm. So at a 1/750s the fan completes 1.104 revolutions during your shutter opening. A blurred spinner would be the result.

[Edited 2004-05-31 04:04:39]

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 11:14 am
by Jofa
"How do you figure 1/750s is quick enough to show a clear spiral on a landing engine?"

This is 1/750

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Photo © Johan Kellerman


But since you don't believe what i'm saying i'm guessing you will start to convince the forum that this 747 landed with only one engine operational and the 3 others shut down, since you can see the spinners on three engines and not the fourth.  Big grin

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 11:43 am
by dl757md
Jofa

You proved your point on the spinner. I still haven't heard anybody come up with a reasonable expalnation as to why an AC with full left nosewheel and rudder deflection would stay on the runway at any point in the TO roll. There has to be some opposing force. If there was an engine failure why would the crew take the plane?

Dl757md

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 12:06 pm
by MD11LuxuryLinr

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What I got from the photographer's comments on the other thread, the nose wheel was off center from the beginning of the takeoff roll. So, from that, the crew wasn't trying to steer the jet using the tiller. We can only speculate that either the crew accidentally overlooked something or there was indeed a malfunction. Obviously it wasn't too serious because the plane did go on it's merry way after the incident. I guess we'll never really know.

Thanks for the replies..  Big grin

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 3:27 pm
by PhilSquares
This is in response for Dl757. I don't know I wasn't there. They could have gotten a takeoff warning, the #4 engine could have had a compressor stall. I can't really tell if it is spinning or not.

But why do people always assume the crew did something like fail to start the #4 engine? That is just absurd.

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 4:12 pm
by dl757md
Philsquares

I'm sure we'll never know what really happened. I was just trying to front a plausible theory for what we saw in the pic. I can't come up with one that is mechanically related although I'm open to theories. According to Erwin972 the pilot reported 'some system not set right and they had fixed it' and 'he felt confident about the situation to give it another attempt'. Take it for what you want, but it sounds to me like he messed up. After all he is responsible for 'setting the systems right' PRIOR to TO is he not? I'm also sure that if it was really a mechanical problem resulting in the situation in the photo no pilot in their right mind would take the plane without MX performing a satisfactory systems ck. Can you at least agree with that?

Dl757md

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 4:37 pm
by Erwin972
"Would you please post on the following thread the exact state of the AC in the first pic. Was it still moving, just stopped, or stopped for a period of time."

In this picture the aircraft was still moving. 5 seconds later it came to a stop.

Almost from the start of the roll, it could have been seconds, the smoke appeared. The smoke was increasing gradually, then noticeable the aircraft slowed down, came to a stop and smoke drifted away.

Because it was already getting dark I was on my way to the car when I saw the 747 taxiing. I figured 'ok, the last one for tonight' quickly set the camera to 400iso and there it went. I missed the beginning, my first reaction was 'what's that' the second reaction was 'my camera'.

From the moment I started taking pictures the plane was moving and it came to a complete stop. I made 3 pictures, within a total of 10 seconds (I looked at the exif data). The first pic has the nose wheel even a bit more to the left (!), the second one is here on A.net with the most smoke, the third picture is when the aircraft just stopped and shows the nose wheel already centered.

The emergency vehicle was on the spot in exactly 106 seconds (that is the other picture on a.net) after the stop.

Later, looking at the computer screen I realized it was the nose wheel that caused the smoke. About the #4 engine, no idea if it should be like that, the spiral is different in each picture so it is spinning, but I only expected it to be more blurred.

Kind regards,
Erwin



RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 6:13 pm
by Sabenaboy
Well, there is definitely something very strange about this take-off.

I would like to know what destination this A/C was flying to and how much load it had on board. If it turns out that the plane was nearly empty, that would be one more reason to assume that the crew might have tried to take-off on 3 engines, absurd as that may be.
Assuming they had an engine failure early in the takeoff roll, it would be unthinkable that they would have tried another takeoff without technical inspection!

Until we know more facts we can not blame the crew for anything, but that shouldn't stop us from speculating!!  Wink/being sarcastic

Philsquares, yep, I know this assumption of a crew trying to take-off on 3 engines sounds absurd, but... not impossible.

I would REALLY like to find out what happened here!!

Regards,
Sabenaboy

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 6:47 pm
by Sabenaboy
Well, this picture:

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Photo © Marinus Bergsma


says that the 747 departed empty for Manchester on Feb. 23, 2004.
Could it have been the same load and destination on may 28?

I would REALLY, REALLY like to know what happened with this takeoff.

Regards,
Sabenboy

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 10:20 pm
by PW100
How do you figure 1/750s is quick enough to show a clear spiral on a landing engine.?
I'm not sure what engines are on this plane so lets take the GE CF6-80C2F for example. 100%N1 fan speed is 3450rpm. Ground idle is 24%N1 or 828rpm. So at a 1/750s the fan completes 1.104 revolutions during your shutter opening. A blurred spinner would be the result.


I'm affraid you got rmp [revelutions per minute - 60 seconds] and shutterspeed 1/750s on different units.
Fan speed at take-off power is indedd less than 3600 rpm, which equates to 60 rpm per second. Shutter speed of 1/750s would result in 60/750 = 0.08 revelution during shutter opening, which is more than adequate to get a reasonably clear spinner spiral. Even 1/400s will do the trick.

The answer off course is that the other engines don't have such a spinner spiral. Furthermore, from Erwins reply 21, it looks like the crew already closed the throttles at the time the pic was taken, so probably the fan wasn't spinning at 3500 rpm but more towards idle rpm, which is below 1000 rpm.


I would say that the crew had no idea that the nosewheel was so much off center. From their flight deck position, they can not see that. The Tower probably would not have noticed it either, they would only see smoke [wonder if the Tower reported to the crew that the smoke came from the nosegear, or did they report just "smoke from tyres/gear" or so?].
Heck, even Erwin [the photographer] didn't notice that the nose gear was 90 degrees off centre until he studied his photos at home, yet he was even in prime position [next to the runway, as close as you can get at AMS] to see it. Good changes are that the crew thought that maybe a brake was stuck locking up a tyre causing the smoke. I bet they won't enjoy seeing this photo knowing that they took off normally after the incident . . .

PW100

PS Erwin, congrats for the great photos. Well done!


[Edited 2004-05-31 15:22:45]

RE: How Do You Suppose This Happened?

Posted: Mon May 31, 2004 11:34 pm
by av757
A real technical fact about the nose wheel steering systems on the majority of the Boeings that I have flown are interconnected, the tiller and the rudder pedals. On the Boeing 727, 747, 757/767 the nose wheel steering tiller turns the nose wheels to the full extend of travel left or right and overrides the rudder pedal steering, and the rudder pedal steering provides a small amount of nose wheel steering to occur.

In the case of the Boeing 757/767 the tiller provides 65° left or right in either direction and the rudder pedals 7° left or right in either direction.
I couldn´t find my notes on the 747.

Regards:
AV757

RE: How Do You Suppose This Happened?

Posted: Mon Jun 07, 2004 4:08 pm
by Sabenaboy
Well, perhaps they were doing a one engine out ferry flight? ( Or training for such a procedure?)