Tech Log The very best in practical technical discussion on the web


Old 2nd Jul 2009, 20:54
  #2761 (permalink)  
Join Date: Jun 2009
Location: Iowa
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
I find it sad with todays technology that the control centres along the route had no idea what was going on. I'm glad that I now operate in areas of good communication & radar coverage. There is no excuse......apart from penny pinching.
While it is indeed possible to extend radar coverage to every part of the globe, it's not cheap. Radars that are affordable to non-defense entities are not really powerful enough to stretch over those large bodies of water and you need to base them on land. Even then they're expensive to operate. The only radars really powerful enough to cover that much water would be extremely high power over the horizon radars from the cold war era. I don't think anything like that is really feasible for any country in South America or Africa. In essence, there was nothing along the route to communicate with.
jeremiahrex is offline  
Old 2nd Jul 2009, 21:04
  #2762 (permalink)  
Join Date: Jan 2008
Location: Pretty far away
Posts: 316
Likes: 0
Received 0 Likes on 0 Posts
and again, if you find yourself for whatever reason, technical or operational too close to any ugly weather out there, you just deviate, and worry about all the other stuff when you are out of danger..

Absolutly right and more than often have had to tell F/O to deviate eventhough I had no contact. each time they were very shy about it and I really had to insist.
Furthermore these cases are well documented and planned. Descend or ascend 300 ft, lights on, broadcast on 123,45 and 121,5. Report to ATC when possible. If not, file an ASR. That's a real no brainer !!

As I said before, the BEA chose its words very carefully and I was astonished at the emphasis they put on the ATC. What on earth has it got to do with what happened ??. I'd call that window dressing to say the least.
Everyone used to this part of the world knows how crappy the ATC is and has been for 40 years.
Me Myself is offline  
Old 2nd Jul 2009, 21:09
  #2763 (permalink)  
Join Date: Jun 2009
Location: Bangkok,Thailand
Posts: 106
Likes: 0
Received 0 Likes on 0 Posts

Razoray is offline  
Old 2nd Jul 2009, 21:11
  #2764 (permalink)  
Join Date: Mar 2001
Location: us
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts
EGMA, from the French language version.

This is the plot of the first day of recovery of parts of the airplane and bodies, June 6.

Generally, the items are centered about 3.30'N and 30.30'W. The VS was recovered on June 7, and it and other items recovered on that date were retrieved a bit west and north of the items retrieved on June 6.

Previous attempts to post charts of the current and drift for this area in this forum have mostly been short-lived. However, the drift and current over this period of time would suggest that the items and bodies moved more east and north of their position on June 1, rather than moving to the west or south.

From June 9th onward, no bodies or items from the plane are recovered from the area south of the latitude of Tasil.

The Brazilian Air Force search grids prior to June 6 were generally along the track and east of the track. Perhaps if the search grid for June 2 had been done west of the track, rather than the eastward grid that was done, the wreckage and bodies may have been sighted sooner.

Last edited by SaturnV; 2nd Jul 2009 at 21:29. Reason: add info on subsequent days
SaturnV is offline  
Old 2nd Jul 2009, 21:41
  #2765 (permalink)  
Join Date: Jun 2002
Location: Orlando, FL, USA
Posts: 108
Likes: 0
Received 0 Likes on 0 Posts
The mystery continues to grow and the plot thickens.

We now have the much awaited Preliminary Report. You’ve all read it and so have I. It refines some information that we already knew, and introduces a new opinion that most of us did not seem to share before its release. The Board conjectures that the aircraft did not break up in flight but struck the ocean in a level attitude and right side up. That may be nice to know but it does not answer the question that we are all asking: Why did the crew lose control of this aircraft?

The evidence of compression is significant but it does not actually tell us if the entire aircraft stuck the surface at the same time, or perhaps only major sections of its structure, or if that actually occurred at all. Was it in one piece; two; three? No one knows.

As may have been anticipated, some of us are eager to embrace this new theory of belly impact, in what is assumed to be one piece, as factual; others, like me, remain skeptical.

While the Board has better data than we do, they do not have enough data to reach any definitive conclusions. Thus, they have been forced to form some opinions based on what little evidence they do have. What they have issued is an educated guess – an opinion – nothing more. We should all recognize that truth for the reality that it is.

Let us not forget that all AI Boards are composed of a number of committees whose membership includes a cross section of the “interested parties”. I do not question their integrity but neither do I ignore their humanity nor their often divergent agendas. We cannot ignore that potentially hundreds of millions of dollars may be at stake and dependent upon the final outcome of this investigation. I do not intend to infer conspiracy; I merely state the obvious.

Whatever the case, their renderings are always an opinion – including the final report – reached by consensus or majority vote. Keep that in mind as you think about what they have said so far at this early stage of the inquiry, as well as what they may say in the future.

The objective of all investigations is to determine within our capability – what happened. But, the true purpose of the investigation is to prevent a future recurrence of the event.

If we are to achieve the purpose, we must determine the factual cause beyond all reasonable doubt. Preliminary opinions are of little consequence; only those opinions supported by definitive facts are relevant. In that context it does not really matter whether this particular aircraft broke up in flight or struck the surface while intact. Whichever of these two things may have occurred, neither one of them is the cause of this accident. Each of them is no more than an after effect – a consequence of the cause.

What does matter is that control of this aircraft was lost while in flight. The crew most certainly did not land in the water - whether in one piece or fifty - because they had a penchant for boating. At this point in time that is all that we, including the BEA, actually know to be factual. The consequence of that loss of control was a fatal crash in which 228 souls lost their lives. The true cause of that loss of control is what the Board must ultimately determine. The rest is educated guess + not so educated guess.

Unfortunately, the location of the accident severely limits the data available to the investigators. If the recorders should not be recovered intact, this mystery will remain unsolved. Fate is the Hunter.
surplus1 is offline  
Old 2nd Jul 2009, 21:53
  #2766 (permalink)  
Join Date: May 2008
Location: UK
Posts: 200
Likes: 0
Received 0 Likes on 0 Posts
I find it sad with todays technology that the control centres along the route had no idea what was going on. I'm glad that I now operate in areas of good communication & radar coverage. There is no excuse......apart from penny pinching.
Actually, "they" are looking, only "they" won't admit it.

Do you really think the US *only* used satellites to "help" discover the crash site? That's no different to flying high over the area and using a pair of binoculars.

Think about it...

ECAM Actions.
ECAM_Actions is offline  
Old 2nd Jul 2009, 21:59
  #2767 (permalink)  
Join Date: Jan 2001
Location: France
Posts: 168
Likes: 0
Received 0 Likes on 0 Posts
OK now we know this :
(Page 23 of the English report).
F-GZCP was programmed to automatically transmit its position approximately every ten minutes.
The crash likely occured within 10 minutes after the last position received.
So the -CP was right on track before the end of ACARS reception nearby TASIL. It's important because on French France2 TV an AF pilot came to speak about this report. The journalist asked him what was she doing there, but the captain could not answer because we can't know he said. All of us have read the IB/AF/LH crew comments on what was their experiences this night with diversions, either to West or East or both ways (AF459) with weather radar set to 160NM max. Following or previous aircraft started deviations well before TASIL around ORARO or even before to join the track only by/abeam ASEBA. I would be very interested to have the ACARS track of the 459 just to have a comparative idea.

Another matter is the very poor coordination between all the en-route sectors, Oceanic or not. I have a question about this.

Page 62 we can read

The aircraft's crew must establish contact with the receiving sector's controller (SAL) five minutes before passing above the control transfer point. However, for aircraft flying towards the north and those flying towards the east, the crews must contact the receiving sector ten minutes before the control transfer point to get a transponder code. This contact does not constitute a transfer of the control of the aircraft.
Can anyone confirm that SAL Control still have a working Radar? The 447 was supposed to be at POMAT at 0343 to get its squawk. even with no squawk allocated, the fact that no primary echo was detected would have been a matter to immediately start an emergency procedure.
Squawk_ident is offline  
Old 2nd Jul 2009, 22:05
  #2768 (permalink)  
Join Date: Dec 2006
Location: Bury St. Edmunds
Age: 64
Posts: 539
Likes: 0
Received 0 Likes on 0 Posts
I've followed this thread from the start but this is my first post and there have been many many well argued and articulated posts which I have followed closely.

The question which still puzzles me is why were there no voice tansmissions received by other a/c within VHF radio range of AF447? VHF ought to be good for range up to 100 NMs and there have been reports of other ac flying similar tracks to AF447 which were closer than that. Was no one monitoring 121.5?

If as now seems likely the ac remained substantially intact from cruising alt to SL the ROD can't have been that great so the crew ought to have had time to get out a distress call. Can anyone explain the lack of RT?

Madbob is offline  
Old 2nd Jul 2009, 22:09
  #2769 (permalink)  
Join Date: Jun 2009
Location: east of 10° west
Age: 63
Posts: 104
Likes: 0
Received 0 Likes on 0 Posts
sorry, surplus1

surplus1 wrote

If we are to achieve the purpose, we must determine the factual cause beyond all reasonable doubt.
no, "beyond all reasonable doubt" is not possible in a lot of cases, and may not be possible in this case..

however, there is a lot of information already available in regards to the "most likely" cause of this accident, and that with a very high probability will be, that an aircraft had most probably encountered extreme weather and control over the aircraft most probably because of this extreme weather had been lost..

it is of secondary importance what additional difficulties had been encountered, like iced pitots, and whatever implications that may have had on the flight control system and the crews interaction..

Thunderstorms are killers, that's it, you may very likely lose control over the aircraft, your aircraft may ice up, you may lose important parts of your aircraft due to high loads, your aircraft may be "airconditioned" by huge hail, your engines may suffocate and die, you may break up in flight or being thrown out of the base of a CB with no room and no reference to recover..

and it makes no difference at all which type of aircraft it was..

so what we learn and should take away from this case already..

avoid CBs at ALL COST, that may help us

P.S.: all the speculation in the thread about pitots, and ALTN Law and what you have here, THAT is pretty useless, I agree, and will not help us..
falconer1 is offline  
Old 2nd Jul 2009, 22:10
  #2770 (permalink)  
Join Date: Jun 2009
Location: LA
Age: 74
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Descent rate/time/distance

It appears that AF447 hit the water within about 30nm of the last position report. (The June 6 location is about 30' north, the currents from June 1-6 would make the location about 30' south.) The preliminary report would give us that the plane was intact and if not exactly controllable, at least not a lawn dart. We have no way to guess when things went really bad, but we know they started to go bad about the time of the position report.

How fast can you descend from FL350 and still have a mostly intact plane capable of a horizontal orientation by the time you get to the wet stuff? Alternately, assuming the engines shut down for some reason at altitude and wouldn't come back, how slowly can you go down? Keep in mind you want to hit ground within 30-100nm of the initial problem. (Why do I assume the engines shut down? Just because it means you aren't going very far; there is no proof or even indication that they actually did.)
WhyIsThereAir is offline  
Old 2nd Jul 2009, 22:18
  #2771 (permalink)  
Join Date: Mar 2001
Location: us
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts
Madbob, LH507 flying 20 minutes ahead, monitored 121.5 the entire flight, and heard nothing from AF447.
SaturnV is offline  
Old 2nd Jul 2009, 22:29
  #2772 (permalink)  
Join Date: Mar 2001
Location: us
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts

Here is the plot of the search area for the pingers.

The primary area being within the circle.

The search plot suggests that if AF447 deviated from the track, it deviated to the west. Such would be consistent with the pattern and sequence of wreckage and body recovery, given the drift.
SaturnV is offline  
Old 2nd Jul 2009, 22:44
  #2773 (permalink)  
Join Date: Aug 2006
Location: London
Posts: 51
Likes: 0
Received 0 Likes on 0 Posts
ECAM actions:

Do you really think the US *only* used satellites to "help" discover the crash site? That's no different to flying high over the area and using a pair of binoculars.

Think about it...
Sorry, don't understand your point. What are you trying to say?
320 driver is offline  
Old 2nd Jul 2009, 23:05
  #2774 (permalink)  
Join Date: Jun 2009
Location: SPAIN
Age: 65
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts

This stall i really feel was at low altitude as if they were still flying and maybe looking to ditch. There is no evidence that they were not trying to ditch and this impact type certainly points to a possiblity.
If they were trying to ditch (a la Sully) certainly the passengers were fitted with their inflatable lifejackets .
So far .. no bodies were found wearing those lifejackets .. and the lifejackets found were not inflated.
So far I reject the possibility of a voluntary ditching .. and I don't reject big pieces of this plane falling from the sky ...
I'm more suspicious about the plane in one piece falling in the water.

LeandroSecundo is offline  
Old 2nd Jul 2009, 23:18
  #2775 (permalink)  
Join Date: Apr 2009
Location: Petaluma
Posts: 330
Likes: 0
Received 0 Likes on 0 Posts
From one viewpoint, if the a/c was airworthy it could glide quite a ways, but to what end? Over the open sea there is no reason to forestall the inevitable contact with water. Give it time to configure with pilot selected drag for water landing. If it was airworthy and making power, try for diversion. If compromised structurally or power wise, and a water landing was inevitable, life vests would have been donned. If even an unsuccessful ditch, some would likely have survived, but there were no bodies with water in lungs. Multiple Tx would have been made, some signal sent.

If the BEA are correct and a/c was intact until hitting the water, the 'forte acceleration' would most likely have claimed all souls. As has been stated, the BEA's position just smells a little like an informed guess, a little different take on the data. Not as egregious as "It was Lightning", and also not as unbelievable as "they almost made it". I think the tailcone hitting first to disrupt the VS attachments is as good a theory as any. There is no real reason to believe the BEA would "shade" their comments, but neither would one expect them to aggressively push a position (absent good data) that would paint anyone in a bad way. Too many times, however, when "all reasonable doubt" is impossible to remove, it is the flightcrew that ends up holding the bag.

It isn't unreasonable to say that given the originating party, and a need to give the press something, AF looked at the ITCZ, ABI looked at the pilots, (and pitots), the pilots looked at the pitots, everybody looks at ACARS, and truth be told, I am avoiding looking at the pilots.
Will Fraser is offline  
Old 2nd Jul 2009, 23:25
  #2776 (permalink)  
Join Date: Jun 2000
Location: Used to be the Beer Store, now the dépanneur
Posts: 114
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by 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.
If ditching is one of the considered scenarios, no amount of AI and/or Software protection will make it safe, at night, in a thunderstorm, and most likely with heavy seas.

Let me backtrack.

It broke up either:
1-In flight
2-On impact

Since it seems the BEA is shying away from 1) (does not mean it is discounted) then 2) gives us 2 more options:

1-it impacted in some kind of a controlled fashion, including ditching. Given the circumstances, the chances of success were very slim.
2-It impacted in an uncontrolled fashion, and in this case the industry has to determine why (and software can be involved).

An old and bold instructor once told me that when the brown stuff hits the fan, it is too late for protections (meaning they are there to avoid, not save). Back to basics might give you a chance if you're lucky.
Smurfjet is offline  
Old 2nd Jul 2009, 23:26
  #2777 (permalink)  
Join Date: Dec 2002
Location: UK
Posts: 2,487
Likes: 0
Received 25 Likes on 12 Posts
An initiating item in this accident appears to be the blockage of all pitot systems (weather related), which resulted in ADCs degrading / shutting down.
A significant, but not catastrophic problem for the crew is the loss of all airspeed indications. There is a crew drill and flight procedure for this, and based on other incidents it has been demonstrated that the aircraft can be flown with relative safety until the conditions improve – based on weather research, circa 5nm average.
However, it is not know if flight without airspeed in this instance was that easy, either because of the environmental conditions (severity / extent), crew capability / ability, or lack of other flight instrument displays.

The flight procedure relies on engine power setting and attitude information.
  • Power:- Other incidents had identified engine problems in similar conditions. However, these events were generally subsequent to any pitot (TAT) problems (ice shedding vs ice forming) and were cleared quite quickly. Even if the engines were damaged the aircraft could have glided for some time, the engines relit, and systems reinstated; thus the lack of engine power / setting information due to engine problems might be discounted.
  • Attitude:- There has been speculation about ADC - IR interaction leading to the loss of attitude information, but even with multiple ADIRS failure the ISIS should have provided an independent attitude display. However, airspeed – attitude interaction within ISIS should not be discounted.
    Question – of the previous airspeed related incidents, how many aircraft has ISIS vs conventional stand by instruments?
    Another possibility is an erroneous switch selection which resulted in the loss of all attitude displays.

Other airspeed incidents reported instrument indications and alerts which might lead the crew to mishandling the aircraft – over-speed / stall, and it is the result of these which could have developed the accident.
  • Over speed:- This condition might be detected by vibration – buffet or external noise, and up to a point, depending on trim state, the aircraft might self recover.
  • Stall:- In the event of slowing down without ‘protections’ (ALTN law) the aircraft could stall. As I understand there would be some AOA input (stall warning / stall annunciation?) yet at the same time an over-speed alert could be given due to the faulty ADC.
    If the aircraft were flown into the stall then the (over) trimmed condition might further delay the recovery – a possible connection with the recent A320 accident, 737 accident (AMS), and GA incident (the latter two required forward trim to enable stall recovery).
Spinning is discounted as there is no supporting evidence; a spin requires stall and roll conditions to initiate it, also a combination of aerodynamic and inertia aspects which might be difficult to achieve/sustain (ALTN law has a strong roll centring force).

A stall could account for the subsequent high cabin rate and most aspects the impact description.
However, even in a ‘stable’, long duration stall – high rate of descent, it might be expected that the pitot functions and some instrument displays could be recovered as the ice melted. If ice crystals were the problem, then the aircraft only had to exit the conditions enabling the pitot heaters to regain their effectiveness - not a descent below the freezing level.

Thus the focus of attention might be on attitude displays, abnormal procedures, and the trimmed condition when flying without airspeed.
safetypee is offline  
Old 2nd Jul 2009, 23:37
  #2778 (permalink)  
Join Date: Mar 2002
Location: Florida
Posts: 4,569
Likes: 0
Received 1 Like on 1 Post
I had considered that a possible reason that no radio calls to nearby traffic were heard/made was probably because the crew were preoccupied with trying to save the aircraft first.

Again I can't conclusively agree yet that the aircraft made it down in one piece but will have to admit, with this boards validation, that the debris field does not show much scatter. If I continue to accept this I tend to conclude that the aircraft must be pretty rugged to make that drop in one piece.

Thus I am very interested in the nature of the aerodynamic upset that might have begun at altitude.

And as always the difference in this event between the chicken and the egg regarding the ACAR messages.

carry on
lomapaseo is offline  
Old 2nd Jul 2009, 23:45
  #2779 (permalink)  
Join Date: Jan 2002
Location: USA
Posts: 286
Likes: 0
Received 0 Likes on 0 Posts
Of course its pilot error, has there ever been an Airbus incident/accident that was not?
BEA had its day in the sun, and still no clear indication what happened. Even BEA cannot say with any degree of certainty what the situation was, and understandability. So, give it some thought.

Cannot be pilot error, AF would have to assume responsibility.

Cannot be airplane, Air Bus et all now in the soup.

Airplane part(s) – hummmm.
wes_wall is offline  
Old 2nd Jul 2009, 23:49
  #2780 (permalink)  
Join Date: Jun 2009
Location: ATL
Age: 67
Posts: 131
Likes: 0
Received 0 Likes on 0 Posts
What "kind" of force (s) would "grab" the V/S, ripping it of without touching the rudder?
Inertial forces, but the afterbody failed around the vertical, i.e., the VS didn't depart the afterbody, the afterbody departed the vertical.

Assuming the report is factual, it could easily have been backed up with reversion of debris to find ground zero, and demonstration of each item showing signs of downward compression force along the length of the fuselage. That would be convincing analysis, yet it is missing in the report. Won't speculate on what that omission means though.

If they hit wings level, could imply they had attitude. If they had attitude, they could have gotten out of a stall if in one. Flat spin is another matter. Said impact heading was in direction of flight, though don't know how they could know that. Downdraft from the thunderstorm could partially explain crash location proximity to last reported position.

Not blaming this on the pilots, keeping an open mind, without prejudice.

Last edited by ClippedCub; 3rd Jul 2009 at 00:21.
ClippedCub is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.