Usual Tunnel reading?
Not a single word from the PF, hence this is an imaginatory mutual aknowledgement of the problem!
Those informations are displayed on the pilot flying PFD though. And this would be shown at 0210:05 from the DFDR tracks (alternate law prot lost, loss of speed function for caracteristic speed computation, etc.).
Please, don't make up the few data we have in order to fit your theories.

Question raised 3 days ago by bubbers44:

Assuming a blocked pitot (business end + drain) and total pressure trapped inside the tube at FL350 / 275 KCAS / M 0.808 yelds:

FL375 / 302 KCAS / M 0.922
FL380 / 306 KCAS / M 0.944

NB: corrected from an erroneous previous post which I deleted.

Dropped cats and water glasses
 

Try to think about they "why" of the mostly NU inputs during the deep stall ride down I realized I do not have a real "feel" for what the PF was sensing as opposed to seeing on his displays.

So the question to those who know how to calculate such things are:

A: What was the force vector through the PF's seat during the descent given the pitch and other forces?

Aka what would the water in a glass do, we all know where the cat would go (firmly atached to nearest scalp by all available claws).

B:How does this compare to the "real" forces experienced during simulator sessions where due to movement limits some forces (such as acceleration) are simulated by brief movements followed by pitch?

Looking for why the extreme pitch up being indicated may have been disregarded by the PF.
(PF's remark at 02:12:02: "I don't have any more indications" ?)

Could he have been (against training of course) be fooled into thinking the plane was in level flight.

Aplogies in advance if I have missed this I have read most of the posts as they arrive but could have missed some, please provide a link if this has been analyzed before.

And we know you don't like it - lord knows we've heard it enough times... Doesn't mean it's necessarily worse either.

He could definitely see the fact that they were nose-high, which was clearly visible on the ADI indicators - that should have given him a hint. To my eyes it also looks pretty difficult to judge a traditional airliner yoke fore/aft position from the angle of that seat, so I'm dubious as to how much difference it would have made. Please don't try to make the situation fit your particular gripes with the aircraft.

Note I said "perhaps" - by which I meant I'm speculating way out in left field. I'm not saying that's what happened, I'm not even saying it was likely. But given that we've exhausted what we can glean from the data at hand and we're into equally left-field suggestions of byzantine software failures and the like, I thought it should be mentioned as a possibility.

It's amazing that the design and systems (and by implication those that designed and built them) can come in for all kinds of bashing from those who do not know or understand them and it is accepted as normal, yet advance the possibility that a pilot may have lost focus, or the miniscule possibility that he might have fallen asleep and some people are up in arms.

With respect, takata, I don't think you understood what I was talking about.

It would be useful to consider what the reaction to stall warning training is and how it is done. (Or was). Some pages back, a very useful description of the 2005 vintage of that procedure was linked to.

The condition/response set isn't the same issue to address as "reaction to UAS training," which is a malfunction of a lesser order.

EDIT for clarity: what the crew was confronted with is the classic training challenge of dealing with cascading and / or compound malfunctions/emergencies. (Note: some will argue that the more dire may have been a crew induced, but that doesn't change what problems they were faced with solving).
Here's your situation, handle it like a good crew should, oh, and here's another on top of that, off you go ... In situations like that, how you train has substantial influence on how you act (and don't act) in the air.

Perhaps best to leave the tunnel analysis in the Alps, near the Brenner Pass. ;)

Hello CJ;
Vertical speed is a baro-inertial computation. The display is normally inertially-based but the VS based upon barometric computations can be displayed in "degraded mode". Altitude is also a baro-inertial computation, the complexities of which, from what I have read, would take the rest of the thread to convey - but I suspect that both VS and Altitude information would be displayed as depicted in the picture of the PFD just posted. The problem I had in thinking it out was, although the static ports are unaffected and so the source data for baro readings would be available, I just don't know whether an ADR would still transmit valid information while not transmitting invalid information, or whether the entire ADR shuts down. I strongly suspect the former.



The diagram below shows all cautions and warning flags which may be displayed on the PFD.

http://www.smugmug.com/photos/i-FgLR...-FgLRHVn-L.jpg

I'm confident BEA will put the main fault upon the pilot(s), beside some training and A/C design recommendations, to make AB look good.

In turn, this may raise the question, which planes (AB or B) were subject of a hull loss due to "overstress" (AA 587) or simply "not to understand" (A320 XL Airways) the aircraft.

ADIRU.
 

In addition to questions raised and answers given.

The lowest speed value on the speed scale = 60 knots.
CAS set itself on 0 and invalid (NCD) if CAS < 30 Knots (SPD FLAG).
MACH will be 0 and invalid (NCD) if M < .1 = (MACH FLAG).

ADIRU 3 data (normally ISIS) can be used by LH or RH PFD by means of rotary switch.

In respect of Capt, IMO he realized exact what was going on!
After entering cockpit ordered or pulled T/L into IDLE and ordered ND inputs! see LINK

But - if F/CTL SD page was not selected -he was unable to see THS position from this 3rd seat.

Here we have to make a simplification, because we have no real data about the decelleration of the AC during the descent.
If we assume a linear decelleration from 400kts to 110 kts during ~200s
we have a horizontal decelleration of 0,075g.

Then we have to add the effect of the attitude:
If we take the attitude as being 15° we would see:
~0,96g vertically
~0,25g horizontally
with regard to his seat.
From the horizontal 0,25g we have to subtract the 0,075 *0,96 so we end up with +0,18g felt horizontal acceleration with regard to the seat axis and close to 1g vertically.

All in all the pilots should have felt a relatively stable acceleration feeling with normal vertical g during the descent phase after reaching the -10kfpm
Taking into consideration that the decelleration might have been degressively, the acceleration feeling could have been progressive to some extent.

DozyWannabe,

That I like it or not does not really matter, that the sidesticks as implemented by Airbus deprive a multicrew from 'very nice to know' information is a fact that you're apparently not in the best position to fully appreciate.

Let me tell you your eyes are pretty wrong here.

That 3 pilots got very confused seems obvious - At least we'd like to see the full data, not tomorrow, but yesterday.
There is no free bashing, only constructed critics, but you don't seem to be ready to even consider.

A bit scary to think, and I'm not shy to acknowledge, that after 12 years I still don't know or understand my equipment ... or is the equipment a bit complex after all ?
Never mind, I'll take the next 12 hours at 350 to open my books ... and try to get rid of that ignorance.

Question raised 3 days ago by bubbers44:


Quote:
They were cruising at M .80 at FL350 so how much static pressure change with a climb would it take to go above mach limit with a blocked pitot tube?

Assuming a blocked pitot (business end + drain) and total pressure trapped inside the tube at FL350 / 275 KCAS / M 0.808 yelds:

FL375 / 302 KCAS / M 0.922
FL380 / 306 KCAS / M 0.944

NB: corrected from an erroneous previous post which I deleted.

Thanks DJ77. The only reason I brought this up is to explain why he pulled the nose up. Your data confirms that they had an overspeed warning due to the climb with frozen pitot tubes causing the overspeed warning when static pressure reduced to the lower pressure.

Doesn't this explain how this accident happened the way it did? The PF started a climb when the AP disconnected, got an overspeed and pulled up into a deep stall.

Re forces, yep once at terminal velocity for the attitude there is no vertical acceleration, in other words the forces up and down match so drag/lift component vertically = 1g. Gravity is pulling your backside down with 1g and the reaction from the a/c via the seat is 1g. Same as in cruise. 40 degree roll excursion may spill some water though.

If a ND input acted to increase vertical speed, sensation of weight would have decreased as you accelerated downwards reaction from seat < 1g as the difference gives the net acceleration. So if the stall warner sounded then you might conclude you were on the verge of stalling. If you think that then clearly you can't be stalled now can you. :8

And how do you explain TOGA in an overspeed?
Just curious.

@A33Zab - you're quoting CONF, not me...

I suspect you'd understand it better if you didn't have such a problem with it since 1988. If you hate the Airbus FBW flightdeck so much, why haven't you transferred to Boeing?

No it does not. The numbers are threre to trigger the overspeed warning *if the numbers are valid*. The numbers at that time were not valid, and so if the design flows the way I think it does, the overspeed warning is inhibited.

Just in case my post #792 (p.40) was unclear:
I was referring to the point where v/s had been reduced to 700 fpm, before climb was resumed. I believe stall occurred around 02:11:00 just before apogee, speed at apogee would have been about M.6/185 kCAS (BEA data 2:11:06).

Thank you HN39...I do recall now.

A33Zab, pls be a little patient with this SLF but where is the evidence for a sustained ND input ? The whole discussion about the relative authority of the elevators v THS seemed to be along the lines that failure to manually trim frustrated the efforts to get the nose down. I didn't understand any of that from what I have read as I didn't see a sustained attempt at ND, and in any case there was a post claiming that the elevator design does provide enough authority (although in that dirty air who can be sure).

Sorry if I have misrepresented your argument.

A33Zab:

I don't see it quite as definitively, but I suspect you may be right on the TL's to idle. If the ND inputs were ordered I'm surprised (but only a bit) that the BEA didn't include the CVR for that exchange - in my opinion that would be quite significant.

BEA:
Immediately following the Pilot's arrival, we have 30 seconds of sustained NU though. :ugh:

@ HN39
 

Just for the record.
Totally agree with this.



I like to add that 2nd Speed drop took place around @ 2:11:50
and triggered the NAV ADR DISAGREE message after 10 sec and
FPV Flags on both PFDs.
This event was not caused by Pitot Icing but due to the insensivity of a
pitot probe at hi AOA and pitch (40 + 15) and air flow disturbance due to
fuselage at such a flight path.


"At around 2 h 11 min 40 ,the Captain re-entered the cockpit.
During the following seconds, all of the recorded
speeds became invalid and the stall warning stopped.

PJ2, I reviewed our posts 715-720 and your response was if he drifted one or two thousand feet high the CAS increase with trapped pitot and drain pressure could not significantly be increased. I agree but how about mach limit? That will be the first limit you hit and DJ77 said with less than a 2500 ft climb that limit would have been exceeded by a significant margin. I don't know how to verify that information but when the CVR report comes out we will know. If someone knows how please post it. DJ77, where did you find it?

The only things I feel I believe for sure out of all this are that not latching the stall warning is a clear design oversight and that trimming to near the maximum authority deserves a big red light all for itself (irrespect of 'use manual trim') -that was also a factor at Amsterdam wasn't it ?

However, even if they had recognised the condition and then acted appropriately, recovery from 20000ft would have needed at least a continual sustained 2.3g positive acceleration, and from 10000ft 3.6g. A non-optimal response would have needed more by a factor. With the instruments they had with degraded protections, was subsequent recovery even likely ?

Edit: thanks HN39, merely a factor of 60 out so pls ignore the g's.

CONF_iture,
Are you sure the sidesticks are not visible from the P3 seat, even if you lean forwards? They are on the A320.

A33Zab, quote:
"In respect of Capt, IMO he realized exact what was going on!
After entering cockpit ordered or pulled T/L into IDLE and ordered ND inputs!
But - if F/CTL SD page was not selected -he was unable to see THS position from this 3rd seat."
The THS scale should be clearly visible from the P3 seat, I think: rather more easily than from the P1 and P2 seats, from which you would have to turn your head. In the P3 seat, it would be under your nose.

bearfoil,
My copy of the BEA Update has the PNF making BOTH statements at 02:10:16, quote:
"so, we've lost the speeds" then "alternate law [...]"

PJ2,
Thanks for re-posting that schematic, but what I was trying to confirm is that PFD1 normally gets all its data from ADR1, and PFD2 from ADR2. That seems to be the case.

Re your latest graphic of a possible PFD configuration at start of climb, are you suggesting that the PFD CAS scales had both gone blank? When the PNF announces, at 02:10:16 (before the climb),
"so, we've lost the speeds",
what does he mean? My understanding has been that he is referring to the "characteristic" manoeuvring-speed indices such as VLS, green-dot, and Vmax, not the actual (current) CAS. The "SPD LIM" flag would have appeared next to the strip. At this stage, the ADR1 and ADR2 had not been invalidated – surely that came later?

My thanks, Bubbers44 - not trying to be "right"... heaven knows there are enough theories floating about to fill a tanker, but wishing to have the argument at least countered so it can be dismissed, pondered, etc.

My point was, if the aircraft was essentially level, there would be no increase in indicated airspeed as a result of any blockage. By all indications we have access to, the pitch-up occurred from level flight. It is true that the airspeed may have increased as altitude increased by the former was not the instigating "cause" because the airspeed required the increase in altitude to increase in indication.
It was asked on a previous page, why TOGA if it was an overspeed?

But as just about everyone here now has pondered/asked/puzzled...why pitch-up just for an unreliable airspeed?
I suspect the Stall warning was a result of aggressive pitch up, not a cause for the PF to pull up but as it got worse, the PF (essentially) pulled more, and longer. It isn't the first time a stall warning has been associated with a hard pull on the control column.

Perhaps too, the upcoming BEA 3rd Interim will cover this and many other questions now on the board.

BTW, I have seen significantly different (lower) Mach numbers in the calculation done by DJ77, (more along the lines of the first ones he did) so perhaps confirmation of how the result was derived might be in order. I'm not qualified to do the math but the question needs to be asked. As expressed in an earlier post, I've had an increasing airspeed in climb (B767) and while it reached the overspeed limit it took much more altitude than 3000ft (FL250 > FL280 approx) to do it. Now it's thicker air and the drain may have only been partially blocked reducing the rate of increase.... ;-7

Mr Optimistic;

Pls check your calcs.

HN39, be warned I am an ex-physicist so admire the precision but be wary of the decimal point and I also admit they were wine and excel affected.

Edit^2: see your point, who uses feet per minute ? You are quite right, thanks and apologies to all.

@ GY:
 

Agreed for the 30s, but from his position it will be difficult to see the SS pitch inputs (maybe the L/R inputs to fight the roll oscillations).
Required some time to be informed what took place in the previous minutes?



@CS:


Disagree, the THS indication will be covered by the trim wheels from P3 seat. see picture PJ2: LINK
I've seen pictures from A320 series and here is an obvious difference with A330.

Other question answered.......
 

These statements will clarify some questions asked.

The system compensates almost 100% for trim changes, due to speed and configuration changes. Trim
changes, due to thrust changes, can be too large for the system to compensate, and the aircraft may
respond to them in pitch, in the conventional sense, and then hold the new attitude at which it stabilized
after the trim change.
The pitch trim wheel moves as the control law compensates for these changes.
---------

IF TRIM LOCKED > 8 UP :
MAX SPEED....................................................... ............................................................ ...... 180 KT
If trim is locked above 8 degrees UP, pitch down authority may be insufficient for speed above 180 knots.

PJ2, I'm not trying to be right either, just trying to figure the puzzle out. Since I am also a B757/767 guy I don't know much about the A330 and how all that stuff works, just how airplanes in general fly and wonder why a pilot would zoom climb at high altitude into a deep stall.

I looked up the speed limitations of the A330 just now and see VMO is 330K and mach .86 is mach limit. They were cruising at about 280K and M.81 so the puzzle was with trapped pitot pressure and climbing 2500 ft what would the indicated mach speed be. I have no clue. I agree if they didn't change altitude nothing would change but they apparently did. When the CVR comes out I have a feeling the overspeed warning will be well heard in the background.

A33Zab, thanks.

ChristiaanJ, #871

I was not proposing that any of "my" sets of data should be used on an aircraft ( even if I knew how to prepare such stuff... I don't !)

Of the cast for the "scenario", two are seated, Left and Right...

As I am sure others must have hoped, to achieve some initial, almost a gliding performance, to give TIME.

I had read a lot of the last 400 posts but got distracted reading about Birgenair's black and yellow Mud Dauber Wasp. I had had one or more in my Pitot tubes in 1969, spotted at about 80 kts at KIN. Engineer sent from Base, old catering bad, dumpped,No pax catering available,( Bank Holiday), request Diplomatic Over-flight from Cuba, fly to Toronto for food,fly back to UK using my discretion with a double crew, only a couple of days late. My Chief Pilot thought I had taken all 130+ for a sightseeing tour. It as easier to leave it at that...

bubbers44 and PJ2, re CAS / Mach with trapped total pressure.

I computed them with functions from an old (but long tested) homemade personal software (hey, I can do sfwr). It is not rocket science but I don't know how to post a picture of the formulas used and I fear it would not be clear enough if I tried to edit it here so I think it is better to look at the formulas for CAS (subsonic speeds) at Calibrated airspeed - Wikipedia, the free encyclopedia and for Mach number at Mach number - Wikipedia, the free encyclopedia
To use these formulas you need:
ps = static pressure, pt = total pressure, qc = pt -ps.
p0 = 1013.25 hPa
a0 = 661.479 kts
________FL350 __ FL375 __ FL380
ps (hPa) 238.42 __ 211.48 __206.46

If anyone wants to check this and find different results, please let me know.

I find the overspeed hypothesis not very convincing because it does not add up with TOGA thrust selection, don't explain the zoom climb and I believe it was not observed in previous incidents. However perhaps it should not be completely discarded.

P3 Seat
 

A33Zab,
The link you posted is to a photo taken from the P1 seat, probably in its aft position. AFAIK, we do not yet know where the captain sat or stood during his all-too-brief return to the cockpit. He may have managed to sit in the P3 seat, as I think you suggested.

Regret I don't have a plan of A330 seating, but the P3 seat is likely to be the one used by third crew members, including training and check pilots. It has to offer the best viewing position behind and between the two operating pilots, usually at the back of the centre console. It was my job to spend many hours in such a seat on the A320, so I'm only too familiar with the concept. You MUST be able to see everything to do that job properly, so there has to be such a seat.

Perhaps PJ2 or CONF_iture can comment.

P3 Seat
 

Chris Scott,

According to the flight deck layout from Airbus, you are correct in that the third seat is directly back from the center console. There is also a folding fourth seat that is at an angle behind the FO right seat.

@ CS:
 

View from Seat P3. (I linked PJ2s picture because you can see the trim wheel being above the indication)



http://i474.photobucket.com/albums/r...A333rdSeat.jpg

Was the aircraft stable
 

JCJEANT (POST #840

Hi,

Quote:
"When the autopilot and autothrust disconnect in cruise, one takes over and manually flies the aircraft. With no speed information, the last thing one should do is change anything...pitch or power.The airplane was stable just before the loss of airspeed data. "

Why always repost this speculation ?
By myself I read (and it's not a speculation .. but a fact!) the aircraft was stable because he was in a cruise flight stabilized by the autopilot and auto throttle
When autopilot and auto throttle go out of the loop .. we don't know if the airplane stay "stable"
So maybe .. instead of touch nothing (hands off) the pilot had to act immediately for stabilize the plane
Remind .. the plane immediately banked to right (unfortunately no clue about the bank angle from BEA note ....)
So will the pilot wait the aircraft go in a 30° or more bank angle before react ?

JC

Totally Agree

At the point when 447 entered "something", ALL HELL BROKE LOOSE!

Pitots iced up. Airspeed lost. A/P and A/t kicked off. 32 or more error messages sent. The Pilot warned of "a bumpy ride".
And soon after the plane entered it's ride of doom into a deep stall.
And to me the likelihood of severe turbulance and strong up and downdrafts.
If there is reluctance to "hand-fly" the plane at altitude at all, what happens to a pilot who has never done so in turbulent air.

Are all those things happening at once sheer coincidence? Not to me.

Chris - I do apologize to you and to takata for scrambling my post. My underlying post meant to establish the cognizance of lost speeds and degradation to ALTERNATE LAW at a TIME certain, and not subject to ACARS delays, routes, and signal.

It was at eleven seconds after a/p dropped ( @2:10:05 ), and PF (RHS, In this I agree with takata ) assuming even a three second recognition and speech delay, the CVR establishes that the Cockpit has been made aware by one of the PILOTs that LAW change has occurred eleven seconds after a/p loss.

Could you comment on the idea that involuntary loss of the A/P due control limits exceedance means a drop not to ALTERNATE, but to retention of NORMAL LAW?

For at least two reasons the CVR is the key to a final reconcile of this accident. First, it is TIME perfect, and exceedingly capable witnesses will be heard commenting on the source and progress of the tragic crash?

bubbers44 For my money, your approach is the best I see. Incorporating as it does a connection with the flying Pilots and high altitude hazard, I think you may be very close.

Hopefully BEA will give up a bit more soon

Just a note. The BEA retrieved the fourth seat, but no mention of their retrieving the third seat. This was during the first recovery. (The other two cockpit seats were retrieved with their occupants, and it was the DNA analysis on these two bodies that led the French court to proceed with recovery of other bodies.) One can surmise the BEA may have had an interest in the straps on the fourth seat.

After Ile de Sein swapped crews at Dakar and returned, the second recovery seems to have been dedicated to retrieval of bodies. Looking back, the crew swap may have been to bring on board a team experienced with traumatic death. And it may have been representatives of the French court that were directing the second recovery phase, with the BEA more of an observer.

When the PF made the "left-nose up input" (notice singular), it seemed to solve the (small) problem he had at AP cutout. The next time we are given is 11 seconds later and no further inputs have been made on the SS (that we know of) and the aircraft seems to have been in stable and level flight for that 11 seconds.

Question 1: So if it was such a drastic input to initiate a 7K/ft/mn 'zoom climb' wouldn't it have begun much quicker especially with the speed and altitude they were at?

At that 11 second point into the incident, the note is clear that "the pitch attitude increased and the plane began to climb" keeping in mind this is 11 seconds after the only known control input. Also, the wording (the pitch and the plane did X) leads me to think the aircraft did this as no other control inputs are mentioned.

Question 2: With the different protections removed in Alt law, how would the aircraft increase pitch to such a degree with no inputs? Could turbulence/updrafts be sufficient to induce such a pitch up?

About 15 seconds into the incident, "the PF made nose down inputs" (notice plural). This seems to indicate he made more nose down than up however, these multiple inputs only reduced the climb rate but did not end it. Keep in mind, the THS had not moved at this point, that comes later. The roll left and right indicate to me there was turbulence involved at this time.

Question 3: If one left nose-up input starts such a climb why were multiple nose down inputs not enough to completely arrest it? And since the PF noticed the climb and tried to correct it, why did he let it continue at 700ft/mn for the next 35 seconds?

At 45 seconds into the incident, the aircraft ran out of energy and the AoA increased, setting off the stall alarm. Thankfully, the speeds had returned to over 60K or that might not have happened either (see later on). "The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs."

Question 4: Is it possible, despite the PNF telling PF Alt Law, the PF (whose speeds may have been valid at this time) thought he was back in Normal Law?

That to me is the chain of events that led to the stall with PF holding nose-up and THS moving to max due to those commands. The note is so vague on the fall, almost impossible to raise questions as of yet. My pet theory is the Captain got back in the LHS and took over the last minute but no real evidence except not sure senior PF would have given the stick over to junior PNF.

Thanks to any/all that can shed any light on what I see as the chain of events that all have to happen to lead to an accident of this nature.

From page 13 post #260 - AF447 Thread No.3 and 2725 posts ago.
Since the post above, A33Zab has provided information on the No Calculated Data (NCD) and PJ2 has provided a possible PFD image as a help to interpreting what the pilots were seeing at this time.

I have previously provided some updated timing for when the FPV page data was selected (between 02:11:55 and 02:11:59) and A33Zab has posited that the Capt ordered the thrust to idle. I also suspect that the Capt didn't know that the aircraft had been to FL380 and was in no better position than those in the front seats in understanding the reason for the SW following ND commands.

All were confused by the continuing NU eliminating the SW, and the PF most of all as he apparently didn't realize that the initial couple of stall warnings were short excursions into high AOA.

A system designed to provide warning of an approach to a stall has implemented that warning on the basis that the normal means of avoiding the stall will be taken. If as part of the design criteria an increasing AoA and decreasing IAS were further considered, then the NCD case would have resulted in "STALLED" in large red letters on the PFD.

Now stalling an Air Transport aircraft is what the SW set out to avoid, and the (NCD) lack of data on the PFDs resulted in the, "No valid indications" comment rather than, "We are stalled!"

If it is now possible to rationally explain some unforeseen bi-product of switching to ALT 2 LAW (following loss of airspeed data) that contributed to the "zoom climb" and inability of the crew to get the nose down, then all the A332 series aircraft could be at risk. I don't think that, and I guess that neither does Airbus Industries or the BEA. An aviation psychologist may provide an answer, but the simplistic approach is "action = reward", and that false reward needs to be addressed in the software logic associated with the Stall Warning.

I am not advocating that the FD crew become the servants of computers, though if those same computers had been programed to "save" the aircraft from the "crew", then IMHO none of what we are second guessing would have happened. The crew are given the right to have the final say, and sadly in this accident their interpretation of events turned out to be wrong.

EDIT :: It is worth noting that no control surface systems fault warnings entered the the CMC and resulted in ACARS messages. There was plenty of time for them to be transmitted, and due to the manner in which the BEA produced their Note, it may be safe to assume that there were no control faults recorded by the FDR.