BREAKING NEWS: airliner missing within Egyptian FIR

[BrandonSoMD]

We've seen here the reports of pilots "not hearing" a tailstrike.

I'm a flight test engineer. We did abused-takeoff tests a few years ago on a 707-class aircraft, where we inadvertently struck the tail, requiring skin repairs. We saw the high pitch on takeoff but did not know we'd struck the tail until we landed several hours later. The noise and vibration at full throttle masked any sound of scraping.

It was a relatively light skin scrape, so my experience might not be representative of a strike doing enough damage to potentially cause subsequent structural failure of a rib or stringer. That would require a longer-duration scrape which the pilot would probably note as a hesitation in pitch rotation, even if it was not heard.

[oleostrut]

Upper HS support is present at crash scene.

The HS is attached to the airframe at only 3 points, the 2 aft pivot pins and the jackscrew at the noes.

The pivot pins are held by 2 support assemblies at either side of the fishmouth at the aft most station of the fuselage. These supports are removd to install the HS, then replaced to attach the pivot pins.

The upper aft most station frame assembly is clearly visible in the photo, the jackscrew is there as well, but not recognizable in such a low res pic. A high res pic was posted last night, but is gone now. I went to the source and got a 404 error, so gone for good, I guess.

In second pic, the red lines are the removable support rods that engage the HS pivots, the yellow lines point to their upper mount areas, visible in the other photo.

[andrasz]

@ oleostrut

You mean the jackscrew is the elongated part that (visually) seems to connect the slanted piece protruding from he shredded VS trailing edge and the upper centre of the last frame ?

[oleostrut]

"You mean the jackscrew is the elongated part that (visually) seems to connect the slanted piece protruding from he shredded VS trailing edge and the upper centre of the last frame ?


Yes, it was much clearer in the better (now gone) photo.

Very early in this thread there was an excellent photo of the jackscrew assembly and actuator. Compare this photo with that jackscrew actuator, and you can se that is what we are looking at.

[Prada]

fuel ignition at 0,2 at pressure and -42C

With a fuselage rupture of any sort is it at all creditable that there is any chance of fuel catching fire or exploding at that speed and that altitude. I would suggest not.

It is true that fuel is so difficult to ignite at altitude. Even in engines. But it is not impossible. You need enough initial energy(heat) and reduced airflow to sustain flame. Though I have read that chances to ignite jetfuel reduce exponentially as temperatres and pressures drop. Thats a whole science.

Anyway, rear passengers and seats got scorched somehow. And there was a heavy fire on the plane before it impacted terrain.
I suspect that fuel fire was secondary event, caused by series of events before primary destructive event.

I wonder if this particular A321 had additional central fuel tank or no? If yes, it is located aft of wings inside fuselage.
Standard range with winglets for this plane type is 5900km. Sankt-Petersburg - Sharm el Shaikh distance around 4000km. Anybody knows?

[WNTT]

The tail looks to have had a 'bomb' actually in it! does anyone know of a similar crash where the tail was so de-constructed and parts spread out? Even with Alaska Airlines 261 with a jack screw failure the tail seemed to stay intact but with no pitch control.

In my mind if the tail severed in one go, it would stay intact until impact with ground, but that doesn't seem to what have happened here.

has anyone got a handle on where the APU, HS parts (at least two), tail, and VS lie in the debris field relative to each other? they don't seem to be close to each other.

[MikeJ65]

oleostrut - That does look like it could be the THS actuator still attached to the box section that it mounts to. However, if that is the case, it is displaced about 5 frames aft from where it should be located. Its normal location is also proximate to the aft two pairs of the VS mounting lugs. Displacing the top mount of the THS actuator would possibly also displace these mounting points and account for the splitting of the VS.

Of course, the next question is what generated sufficient force to do this.

[sardak]

oleostrut andrasz
See these posts for photos of the HS install and the jack screw

http://www.pprune.org/9169437-post982.html

http://www.pprune.org/9169622-post1004.html

[TheGeneralElectric]

Could this be another Partnair Flight 394?

Long time lurker. Have been following this thread and thanks all for your thoughts.

A crazy idea: Could a APU mount failure failure due to improper maintenance, loose structure (eg APU) and resonance vibrations jam and break the rudder, leading to the tail coming off?

This happened to Partnair Flight 394 in 1989, leading to the tail coming off and midair disintegration.

https://en.wikipedia.org/wiki/Partnair_Flight_394

[CONSO]

fuel ignition at altitude

It is true that fuel is so difficult to ignite at altitude.

Aaaamen. Re the two flashes reported by US, supposedly one at altitude and one at/near ground- apparently by using Infra-red technology. It **MAY** be that as plane tumbled as a result of loss of tail- HS , what was seen was looking essentially into the aft end of the two jet engines still running or still hot, making a great IR target.

Then of course when hitting the ground would be relatively easy to ignite spilled fuel giving the second IR flash.

Could there be " readable " flashes between air and ground ? Maybe- depending on resolution and tumbling of wings and partial body - but that degree of sensitivity would likely NOT be public information.

[Lonewolf_50]

Regarding the speculation on a possible over-rotation as some sort of initiating event: the discussion on that has been interspersed between much else, but I'll ask the following:

Doesn't an over-rotation like that leave a visual signature that someone in the control tower would see as the plane rotates before lift off? (Sparks?) If so, would not the investigating team already have that input from the witnesses at the airport?

A few pages back it was pointed out that on the A321 contact would be made further forward than the aft pressure bulkhead in the case of an over rotation ... is it reasonably valid to rule out that contributing factor to a structural failure further aft?

Follow up to that:
1. Have any of you had an over rotation/tail drag and not gotten a report from the tower?
2. Did you know a colleague who had that happen, but the tower didn't give them an alert?

-------------

About the American "leak" regarding "maybe it was a bomb"

The official stressed that there has not been a formal conclusion reached by the U.S. intelligence community.

Then why doesn't this "intelligence" official keep his trap shut! This kind of crap upsets me (I am American and I hate how our Intel community has become a home to so many loudmouths). Sometimes, it is best to keep it all close to the vest.
This kind of "loose lips" does not help aviation safety -- it just feeds the rumor and speculation mill.

I wish to thank the mods for their hard work on trying to keep this thread clean.

Let us consider that our Russian PPRuNe contributors feel this loss keenly, so can we please see an end to the acid comments in the political realm? (Kulverstukas, we like bears, vodka, and balalaikas, regardless of how people fee about politicians. ).

[N8477G]

Better debris map needed

What is the first item that departed the aircraft and where was it located? We need a better debris map. A good debris map will answer many questions regarding the sequence of the breakup and will usually point directly at some cause. It may be useful and entertaining to discuss the possible breakup scenarios that resulted from the initial event, but finding the first piece that came off the airframe will tell much of the initial story. If anyone has a more complete debris map than has been posted please share it. In particular - what part(s) were found along the flight path the most DISTANT from the main wreckage? What came off first?

[Ian W]

Originally Posted by oldoberon

Damn I must have imagined the USA has released statements saying TWO heat flashes detected by satellite, one in the air other on ground impact, must stop eating cheese for supper.

Flash from engine(s) break upward into wing(s) on minus 10g or more bunt causing fuel tank explosion and igniting remains of wing and fuselage; second flash on explosion of remaining fuel on ground impact.

Look up "confirmation bias".

Stick with the cheese

[silvertate]

Smott999

Would a tail strike on TO be potentially heard and remarked upon on CVR?

Oh, yes. No mistaking it. BTDT....

.

P.S. Note to Brandon, test engineer.
On a commercial flight, the rear hosties are sitting on top of the tail skid. No way in the world they would not notice, even if you were listening to Radio 2 at the time.

Silver

[Lonewolf_50]

Originally Posted by silvertate

Oh, yes. No mistaking it. BTDT....

Just curious, did the tower see it and give your FD crew an alert over the radio?

[Ian W]

Originally Posted by funfly

With a fuselage rupture of any sort is it at all creditable that there is any chance of fuel catching fire or exploding at that speed and that altitude. I would suggest not.

FF

If it was just a fuselage rupture possibly so.

But when the engines are ripped upwards off their mounts while in climb power you might expect some kind of fire

[Sober Lark]

It is true that fuel is so difficult to ignite at altitude.

Correct, Pan Am 103 didn't explode until fuel laden parts hit the ground.


Are those 20,000 going to be happy to be stranded one day and rescued the next? If Mr Cameron doesn't trust security then he should take the passengers and leave the baggage behind - its only dirty washing anyway.

[dsc810]

@sober lark
That is exactly what Easy Jet are doing
no checked in baggage permitted.

[MATELO]

Then why doesn't this "intelligence" official keep his trap shut! This kind of crap upsets me (I am American and I hate how our Intel community has become a home to so many loudmouths). Sometimes, it is best to keep it all close to the vest.

Catch 22. If the governments knew about a bomb and didn't act and people lost their lives, it would be the other side of the argument. They knew, but didn't tell us scenario.

[rog747]

no hold luggage out of SSH - jeesh

goodness this is extreme

no hold bags no pushchairs no wheelchairs

all will be sent on within 7 days by a courier

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