basimpsn

My Feedback: (5)

That's a good point Bev

P.S Ok how did I get pink

willig10

All:
I am an A&P and also a pilot. I have worked on the 747 series along with numerous commercial and corporate aircraft. I hate it that these things occur. It is sad to say but the loadmaster is the responsible party when the load is being loaded and he is responsible for the security of the equipment being loaded onto the aircraft. That said we probably will never know (due to fire) if the load was properly secured or if an equipment malfunction (tie down straps, hooks etc) occured.

The capatain's duty is to perform a walk around inspection prior to take off to ensure all is well and to back up the load masters tie downs visually

Typical preflight briefing goes something to the order of V1 at 120 knots V2 130. Abort if engine out at marker x,y,z. If during climb we lose an engine we will dump fuel at x.y.z and declare an emergency and return to the field to land. There are variances to the brief but it is standard practice to have a brief and fly per the brief so all in attendance know what is expected in the event of an emergency.

Assuming all mechanical issues were ok and everything was working as advertised, during the take off roll and subsequent rotation, it appears the load shifted and caused a severe aft CG situation. Prior to the stall, the stick shaker should have activated and assisted the pilots by pushing the nose forward. As the video shows the high angle of attack caused a stall and even though stick shaker activation more than likely took place. The plane was unrecoverableand the end result is theloss of lives and equipment.

Looking at the video as soon as the planecomes into view the AOA isextremely high and as the crash sequence unfolds it shows a typical stall/spin scenario. The pilot was a good one as he recovered the aircraft and kept it from developing into a full spin.

Just a sad day overall.

Regards
Glenn Williams

willig10

Also forgot to mention. Someone mentioned smoke from the engines during take-off. The 747 uses high bypass engines which are split spool and only 10 to 15 % of the thrust comes from the engine itself (out of the tailcone) the majority of the thrust comes from the compressor usually about 90%. These engines are more fuel efficient, quieter and cleaner burning than a "pure jet" engine.

Regards
Glenn Williams

AmericanSpectre505

Bagram Airbase has "VERY TALL" mountians all around it! Plus the altitude is high and the air is thin. The margin for error is small for cargo planes. I have seen that bird on the runway in Bagram over the past 3+ years going back and fourth to AFGH. The comment was made your an F-18 driver? Very poor taste or choice of words, if that's the case.


"God Bless the men lost and the families left behind"


Bill

(Covered Bird, Professional crew). I took one just like it out of a base in South Carolina, overseas,......

hook57

My Feedback: (21)

Huuuhhh! Would that be the LPC or the HPC? Basically, on lowor high bypass fans:
1) Air enters the core via the fan which is drivenby the LPT
2) Majority ofit is accelerated out the back (thrust)
3)Aportion entersthe core and is routed tothe LPT and the HPT compressors
4) It's compressed, mixed with fuel, ignited, becomes energy (heated air)
5) The heated energy andpressure energy result in rapidly expanding air passing thruthe turbines (turbins),they spin thehigh and low pressure turbines,and they spin the fan (and the compressors) 6) Air exits the turbines (thrust) and the engine through the exhaust nozzle (a little more thrust)
It's an old process, they suck, squeeze, bang, an blow, so do recips.
Just adding 2 1/2 cents. As a former freight dog, load shift ain't fun
hk

willig10

You would be correct if this was a pure jet. The engine is a split spool engine and the 3rd stage wheel drives the compressor. The compressors 1st stage is the fan. It is the fan that provides around 90% of the thrust. The other 10% come out of the exhaust cone. Another way of determining a high bypass engine is in it,s thrust reversing system. A pure jet will have clam shell doors that are mounted on the aft end of the engine and when activated they cover the exhaust and divert the exhaust/thrust forward. On a high bypass engine the thrust reversed is mounted on the aft end of the inlet. This is called a cascade reversed and it diverts the fans thrust forward. This is because the majority of the thrust is in the 1st stage fan/compressor.

Glenn Williams

invertmast

My Feedback: (23)

First its the compressor that provides the majority of the thrust, now the Fan.. WHICH ONE IS IT!!!!1



Its the FAN!!!!!!!!!!! the compressors just provide the compressed air for the engine core, which turns the FAN

eddieC

My Feedback: (2)

It's called fan and compressor interchangeably. Depends on the manufacturer's term, and some call it both. It accelerates AND compresses the air. In full-scale class (FlightSafety and SimCom), depends on who is teaching that day. 

invertmast

My Feedback: (23)

Its tur Bain

bevar

My Feedback: (27)

Guys,

From a discussion board at work.

Beave

>>EDITORS NOTE: The following is an independent analysis and is in no way an official investigation.

FACTS FROM VIDEO
- Aircraft had a very low forward airspeed during the stall and on impact.

- The landing gear was down.

- Engines emit smoke just before the stall.

- Flaps were in a takeoff position.

- There were vapor trails from the wing tips. horizontal stabilizer, and engine pylons as the aircraft lost altitude.

- Engines shoot forward on impact approximately 200 feet.

- Left wing dips at the beginning of the stall, followed by a rotation to the right that ends when the bank angle approaches 90 degrees.

- The fire indicates there was a light right headwind/crosswind.



ANALYSIS
Informal analysis: (based on observations, assumptions, and deductions). Note, investigators will be reviewing all evidence, and the conclusions will be more soundly reasoned than this analysis based solely on the video footage.

The fact that the gear was down indicates that the crew was experiencing problems immediately after takeoff that focused their attention elsewhere. From the video, you can see the aircrafts speed was deteriorating. There is a transient smoke stream from the engines just before the stall, which is an indication of an acceleration of the engine cores RPM the crew were likely firewalling the throttles. There was a light dip of the left wing at the beginning of the stall. The pilot likely countered with right rudder, a correct but excessive input that caused the aircraft to enter a spin to the right. At this point, airspeed appears to be nearly undetectable but probably around 100 knots.

Swept wing aircraft, especially ones with high angles of sweep like the 747, pitch up at the last moment of a stall before the nose drops and airspeed is recovered. In the video, the nose does not drop until the aircraft is on its side and rapidly loosing altitude. Once the aircraft is on a knife-edge, the airflow will cause the vertical stabilizer to weathervane. This brings the nose down. During this time, the right rotation also stops. If there had been an engine failure, the rotation would have continued in the direction of the failed engine. As the wings are brought level, the nose down attitude remains stable through impact. At this point, there are vapor trails from the horizontal stabilizers and wing. This indicates a high pressure differential which is clearly from the high angles of attack on the surfaces.

The crew had a controllability problem that was present from rotation. Pilot training and instinct is to lower the nose if the aircraft is pitching up. This wasnt possible. To put this aircraft in the position it was would have required excessive nose up elevator or excessive rear Center of Gravity (CG). Since this was a routine flight and the aircraft had not likely had major maintenance causing a critical failure of the flight controls, a rear CG is the likely problem.

This is also indicated on the final moments prior to impact. Had the CG been in the proper location, the nose down pitch would have continued as the CG forward of the wings lift would have accelerated towards the earth from gravity while the wing resisted this acceleration due to airflow (drag) on the wing, even with a major failure of the trim or elevator. Just prior to impact, the pitch remains mostly stable, indicating the CG was between the wing and tail, and the weight on each was proportional to the lift being generated. The proportion of the surface area of the wing to tail surface would be equal and inversely proportion of the CG between them. Ie, if the surface area was 70% wing and 30% tail, the CG would be 30% back from the wing, or 70% forward of the tail.

There are many other possibilities, example pilot error. Though this is unlikely, these must be considered until conclusively found otherwise

bevar

My Feedback: (27)

Glenn,

FYI...a stick shaker just shakes the yoke...it does not move it. You are thinking of a stick pusher which most large and heavy jets do not have. That being said, I don't have any time in the -400 so maybe it does have one.

Anyone know if the -747-400 has a stick pusher?

Beave

rcjets_63

My Feedback: (4)

Blah blah blahtitty blah blah! A bunch of rantings from professional and highly qualified pilots who actually are fly these things. What a crock of hooey!

When I want to know the truth, I turn to the real experts on RCU who knew a guy who knew a guy who once saw an airplane!

Regards,

Jim

eddieC

My Feedback: (2)

bevar

My Feedback: (27)

LOL!!!

Oh sure LP...like you actually know someone who really fly's big jets? Uh huh...sure you do...LOL!

Beave

willig10

Ok I,m out. Tried to keep this thread educational from not only a pilots perspective but also as an A&P and 1st hand experience. You can't fix stupid and I ain't even going to try.

bevar

My Feedback: (27)

Glenn,

Do you fly Transport Category jets (type rated)?

Just curious, that's all.

Beave

Selleri

Terrible accident, got many buddies working for AAI in that area.

AAI operated that plane until last year when they moved it on.


It's one of those cameras that gets the date settings from a file loaded from memory at powerup.

bevar

My Feedback: (27)

One final note.

The jet was on a fuel stop. The MPAVs had been loaded previously at the original point of departure...not Bagram.

Beave

Molnar142

My Feedback: (38)

Beave,

Thanks for sharing. Very informative.

Turbotronic

As far as the smoke goes from the engines is does seem likely that given the extreme angle of attack the fans and compressors downstream suffered flow breakaway from the fan inlet, upsetting the combustion and so smoke is the result of poor combustion?
May also caused thrust to deminish, a no win situation.
Just a thought.
Sad
Andre

GrayUK

Tragic loss of a brave crew .
My condolences to the families of those who died.
From my own point of view it looks like a rearward CG to me, classic ‘wobble’ as the stall becomes dominant followed by a drop of a wing.
I am sure the investigators will find the cause.
Very upsetting to watch.
[&o]
Paul G

David Gladwin

Unlikely Andre. The aircraft did not have a full fuel load, it was headed to Dubai so the probability is that they were using derated thrust (very common, actually the norm, on jet transports, full thrust is rarely used. ). My view is that as soon as they realized they were having a problem on rotation the thrust levers would have been slammed fully forward resulting in some slight smoking. A full fuel load from Bagram to Dubai would almost certainly have put him above MLW for the arrival at DXB

That said, the feeling of the professionals is that cargo shift was almost certainly the problem. The FDR will show stab trim and elevator positions and pitch rate so it will be obvious that if the was a rapid pitch up with full down elevator and the stab trim in the correct position or running to nose down it HAS to have been cargo shift. However the approach of the accident investigators is to rule nothing out until it has been definitely eliminated. (early speculation on the C5 crash at FFM was cargo shift, but investigation showed it was an uncommanded thrust reverser operation) If the stab position had been grossly in error, ie outside the green band the TOCW horn would have sounded as the thrust levers were moved forward. What is also KNOWN is that the gear remained down, suggesting there was serious distraction immediately on unstick.

There has been some speculation about a "tactical departure" (ie max angle climb to avoid SAMs) but no pilot is going to fly a pitch attitude which would allow speed to fall below V2 which is minimum acceptable engine out climb speed so perfectly safe.

The preliminary report is due soon but there is some very professional discussion by people who know what they are talking about on www.pprune.org.

Let's wait for that report before we have more amateur and uninformed speculation.

David Gladwin.

Turbotronic

You are most certainly correct. I am not an aviation expert . The FDR will have the last say I suppose but it seems certain the crew was in an unrecoverable situation due to a number of factors stacking against them.
Absolutely awfull to comprehend.

alasdair

I used to fly the 747-400 for BA. Ours only hada stick shaker,no stick push, and I expect that is normal for the type.

The only jet transport I have come across with a stick push was the HS Trident.

What is the point of speculating? We should get the official report based on CVR and data recorder evidence soon enough.

David Gladwin

For those interested here is the thread:

http://www.pprune.org/rumours-news/5...bagram-31.html

Alasdair, as well as the Trident the VC10 also had a pusher, T-tail being the common aspect, but all three Boeing types I have flown were shakers only. After the Trident and 1-11 deep stall accidents I was a little anxious when on BOAC VC10 stall training we went as far as the pusher, and in the aircraft, not the sim. !

As well as the Bagram 74 crash another very worrying accident was the very recent in-flight breakup of the USAF KC135 with the loss of 3 crew members, but as Alasdair says, there's no point in speculating, the investigation will get to the root of the cause.