AF447

[SaturnV]

Pj2, the search grids are for a 40 nm radius circle centered on the last known position "derniere position connue" with additional grids to the west, and to the north to Tasil. Unfortunately, the chart only gives longitude for the squares, and no latitude. The search grids do not extend to the east or southeast beyond the circumference of the circle.

"Le premier message de position (message de type AOC) a été émis le 31 mai
à 22 h 39. Le 1er juin à 2 h 10 min 34, la dernière position reçue était +02,98°
(nord) de latitude et -030,59° (ouest) de longitude. La position transmise est
la position FM de l’avion. En conditions normales, cette position est proche de
la position GPS."

[SaturnV]

The VS en francais, for those who doubt the English version.

La dérive a été endommagée pendant sa récupération et son transport mais les photos disponibles permettent d’identifier les dommages qui ne résultent
pas de l’accident. Les attaches du milieu et de l’arrière avec les fragments de cadres de fuselage associés sont présentes en pied de dérive. Les déformations
des cadres montrent qu’ils se sont rompus dans un mouvement vers l’avant avec une légère composante en torsion vers la gauche.

avant = forward

[lomapaseo]

Are some of you describing a scenario where the aircraft falling looks like the video of the F117 airshow crash over Baltimore MD?

[BOAC]

I fear this is now going badly for AI and all who promote FBW and the 'protection' offered by multi-redundant systems and software.

IF the a/c had been thought to have broken up at high or medium level due to 'exceptional' turbulence' then Force Majeure could have been declared.

As it is, barring some unknown other structural failure (HS or forward section separation?), it is looking as if all these 'protections' didn't. There is the bad news for a 'failsafe' design.

I sense this will reverberate heavily.

[hellsbrink]

<off to lurk again, even my French is enough to read that.... It just doesn't add up>

[HarryMann]

Can I ask again, a recent question of mine that wasn't answered at the time

In the cruise with relatively aft c.g. (due to trim drag tank being full/relatively full)

What is the effect on this aft c.g. posn. (33% MAC?) when the system reverts to Alt2 law or even Direct law?

Obviously the pitch stability (c.g. closer to Neutral Point) is less strong, wondering if anyone has even contemplated this, let alone flown this config in the simulator?

Thanks...

[hellsbrink]

HarryMann

From the (english) BEA report http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf

1.6.3 Weight and balance
The aircraft left the gate with a calculated weight of 233,257 kg. The estimated takeoff weight
was 232,757 kg (11), for a maximum authorised takeoff weight of 233 t. This takeoff weight
broke down as follows:
• empty weight in operating condition: 126,010 kg,
• passenger weight: 17,615 kg (126 men, 82 women, 7 children and one baby (12)),
• weight in cargo compartment (freight and luggage): 18,732 kg,
• fuel weight: 70,400 kg.
(11) A quantity of 500 kg of fuel had been taken into account for taxiing between the ramp and takeoff
brake-release.
(14) Air France applies a standard weight of 91 kg for a man, 72 kg for a woman and 35 kg for a child,
which is compatible with the European regulations.
18
The on-board fuel weight corresponded to forecast trip fuel of 63,900 kg, route factor fuel of
1,460 kg, final reserve of 2,200 kg, fuel to alternate airport reserve of 1,900 kg and 940 kg
additional fuel. An LMC corrected the definitive load sheet to take into account one passenger
fewer without baggage.
The balance corresponding to the aircraft’s takeoff weight and given on the definitive load
sheet (after LMC) was 23.3% of the MAC, for a forward limit of 22.7% and an aft limit of
36.2% at takeoff.
On the basis of the operational flight plan, it is possible to estimate the trip fuel at 27.8 t after
a flying time of 3 h 41 min (13), the aircraft would then have had an estimated weight of 205 t
and balance comprised between 37.3% and 37.8 % (14), which is within the limits of the operating
envelope (Operating Manual TU page 12.28.10.9).

[Will Fraser]

It truly doesn't seem to jell. If a/c impacted "flat" with high velocity, how did the VS separate 'forward'. Likewise, if the VS failed at altitude (separated) to fail forward the a/c was travelling 'tail first'. I also don't get completely the 'Ligne de vol'. Do they mean that the heading of the a/c was in its planned direction? That would be coincidental without directional control. How could that have been determined? Similarly, if the VS separated 'on site' why no major dimpling, compression, or tearing?

Its condition still suggests an airborne failure, leaving the Fuselage to decelerate and perhaps 'flutter' to the sea before the major portion of the airframe.

[gonebutnotforgotten]

Aircraft in Direct law?

Takata

Are you sure it is as easy to fly as you suggest:

Well, at FL350, the aircraft is flying level and all Airbus are flown in direct law without much trouble (ask Lemurian, it is like a 737). They have even been certified like that, before introducing the various level of fligh envelope protection. Not a single report from any previous freezing incident included the quote: "we were left with an uncontrolable aircraft impossible to be hand flown because A/THR and AP disconnected"...

The preliminary report says (note on page 54):

Note : la loi de commande alternate 2 est une loi en facteur de charge en tangage et loi directe en roulis. Seule la protection en facteur de charge reste disponible. Dans certains cas, les stabilités haute et basse vitesses peuvent également être disponibles.

As I understand it there is no way for the crew to revert to direct law at FL350 (though I gather there are some at low speed). So my previous comments still stand, I wouldn't be confident that my basic handling skills, such as they were, acquired on conventional aircraft, would have served me well on that night. To judge from this thread, not many AB pilots have thought through how they would control the aircraft in this condition, and it looks as if the FCOM doesn't help a lot either.

[Rustum]

Forward momentum

Hellsbrink:

VS broke off in a FORWARD direction......... I do hope that was a mistranslation.

SLF here and I have a few 'common sense' questions because I do not see a problem with the VS having come off with forward movement:

1. Would it be correct to assume that the plane did not fall quite like a brick, i.e. at a right angle, into the ocean?

2. That some forward momentum sheared the VS's attachments, these emerging as weak points at the moment of impact because of uncommon forces acting on it?

Thank you

[Grayengineer]

The VS would have torn off forward if the a/c had some forward speed and abruptly stopped, since the VS wants to keep it's forward motion (Newton's First Law).

[slip and turn]

I only have schoolboy French but does not 'rompus dans un mouvement vers l’avant avec une légère composante en torsion vers la gauche.' indicate 'broken in a forward motion WITH a LIGHT (not heavy*) torsional component to the left' i.e. spin?

Edit: Sorry everybody - had to have my French corrected by Jig Peter "légère" = LIGHT Thanks Peter

[jcarlosgon]

HarryMann

Can I ask again, a recent question of mine that wasn't answered at the time
In the cruise with relatively aft c.g. (due to trim drag tank being full/relatively full)
What is the effect on this aft c.g. posn. (33% MAC?) when the system reverts to Alt2 law or even Direct law?
Obviously the pitch stability (c.g. closer to Neutral Point) is less strong, wondering if anyone has even contemplated this, let alone flown this config in the simulator?

Good question, that some of us, moving from A310 to A330, ask. On the 310 the turbulence procedure includes forward fuel transfer, but not on 330.

I’ve only flown Alternate Law in the sim at low altitudes, so the CG is always ahead of about 28%. In cruise is about 36 to 38% most of the flight.

[Grayengineer]

Impact Springback

With regards to debri and detachments at impact. With such a high vertical deceleration many of the structural componments will act like springs and after being deformed will spring back and may cause great internal stress revisted by the springback. This could have "thrown" the VS and other objects away or within the a/c.

[Jig Peter]

French

@slip & turn

"légère" = LIGHT
Salut !!!

[Meikleour]

Lemurian,

In my incident we were in cirrus cloud with ice flowing up the windscreen (SAT -50C note!) when all speed indications to the left PFD were lost (Vmax and VLS came together) and right PFD speed dropped to an inaccurate 160kts. A/P and ATH disconnected. The ECAM was almost unreadable due to it constantly streaming and changing. Alternating `STALL, STALL` and high speed warnings received. What was initially the most pressing problem was to maintain the speed down to the ALT2 MMO of .82M versus normal MMO.

Once out of icing after a priority descent the probes cleared and the flight continued for ~1.5 hrs to destination - still in ALT2 law. This happened 14 years ago and resulted in several changes to the hardware and software of the A330.

[Graybeard]

I believe the aft fuselage that supports the Vertical Stabilizer is unpressurized, and may not have to be as strong as the pressure vessel.

The plane hit the water tail-low. That could have forced the aft fuselage to bend or break upward into the rudder, ripping the entire assembly free, and leaving the damaged bottom of the rudder as evidence.

GB

[SaturnV]

Flights preceding and following AF447:

Flight LH507 (B747-400) preceded flight AF447 by about twenty minutes at FL350. The crew reported that it flew at the upper limit of the cloud layer and then in the clouds in the region of ORARO. In this zone they saw green echoes on the radar on their path, which they avoided by changing their route by about ten nautical miles to the west. While flying through this zone, which took about fifteen minutes, they felt moderate turbulence and did not observe any lightning. They lowered their speed to the speed recommended in turbulent zones. They saw bright St Elmo’s fire on the windshield on the left-hand side. The crew listened into the 121.5 MHz frequency throughout the flight without hearing any message from AF447.

Flight IB6024 (Airbus A340) passed at the level of the ORARO waypoint at FL370 approximately twelve minutes after AF447. The crew saw AF447 take off while taxiing at Rio de Janeiro. When passing the INTOL waypoint, they encountered conditions typical of the inter-tropical convergence zone. These conditions were particularly severe 70 NM to 30 NM before the TASIL waypoint. They moved away from the route by about 30 NM to the east to avoid cumulonimbus formations with a significant vertical development, and then returned to the airway in clear skies close to the TASIL waypoint.

Flight AF459 (Airbus A330-203) passed at the level of the ORARO waypoint approximately 37 minutes after l’AF447. The sky was clear but the half-moon, visible to the aft left of the aircraft, did not make it possible to see the contour of the cloud mass distinctly. After flying through a turbulent zone
in the head of a cumulus congestus formation at the level of NATAL, without having detected this zone on the radar, he selected gain in MAX mode. At about 2 h 00, he observed a first echo that differed significantly depending on whether the radar’s gain was in CAL or MAX mode. The TILT was set between -1° and 1.5°. He decided to take evasive action to the west, which resulted in a deviation of 20 NM to the left of the route. During this evasive
action, a vast squall line with an estimated length of 150 NM appeared on the screen, which was set to a scale of 160 NM. The echoes were yellow and red when the radar was set with gain on the MAX position and green and yellow when the gain was on the CAL position. No lightning was observed.
ATLANTICO control, informed by the crew of their decision to avoid this squall line by taking evasive action to the east, asked them to return to the airway as soon as they could. This evasive action meant the aircraft flew between 70 and 80 NM to the right of the planned route. In addition, the crew was authorised to climb from FL350 to FL370.

[Road_Hog]

Originally Posted by Neptunus Rex

As stated in every proper safety briefing, the life jackets should not be inflated until the wearer is clear of the aircraft.

Quite right, but two things, how many aircraft impacts at sea, result in survivors and also, I don't think it was a case of inflated life jackets, I think it was a case of nobody wearing one.

Coming back to an original post/point of mine, AF decleared it a lightning strike as the cause almost immediately and have never explained this opinion. They should be asked to explain this view.

Also, the theory was, a few days ago, that the aircraft must have broken up in flight, because of the two different groupings of bodies recovered, even accounting for tidal/wind conditions. This seems to be contrary to the current official announcement.

[Grayengineer]

Tail low impacts seem to tear the tail section from the pressure bulkhead, but usually, from the pictures of such crashes the VS stays on. Haven't seen enough to say for sure.