AF447 wreckage found

[opherben]

MountainBear wrote

,"I think his time has been and gone. Everything he says sounds good in theory but he fails to mention the critical factor of money. Sims are not cheap, sim sessions are not cheap, practice lessons in the plane are not cheap. How much money is a society supposed to spend in order to save 200-300 lives. Naturally, if it's your life at stake you want them to spend a lot of money. But when it's the other guy, maybe not so much. Whether it is explicit or implicit there is always a cost/benefit analysis going on. Always. "

I beg to differ:
a. Sully landed on the Hudson with his USAF training and experience background dominating, not airline training.
b. The way for cost effective and inexpensive training starts with proper pilot selection, syllabus and training. My son following a few weeks in class then simulator sessions along one week, got his B737NG type rating and is now flying with that top notch airline. Contributors are, again: proper candidate selection, syllabus and training. Decision makers need to understand flight, airline management, and wrap-up this prohibitive cost bull.

Regarding who to spend money on, the study of ethics teaches us that the best way to get life quality is to pursue smart egotism, in which people benefit by donating private resources to their community.

[jcjeant]

Hi,

Two questions I could not find the answer to in this thread (bear with me if I overlooked them):

1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?

2. would a full down sidestick have had the authority to overcome the full up THS later on?

Those questions were already answered
It's YES for the 2 questions if the airplane was acting like it must be in alternate law
Pull up and the THS will go up
Pull down and the THS will go down

[RansS9]

"You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system"

With an AOA probe/indicators system set up to alarm CONTINUOUSLY anytime AOA reaches predetermined level before critical AOA and BEYOND (...sorry sound like Buzz Lightyear) with the addition of a weight on wheels breaker.

Can you envisage any scenario which would lead to a "Nuisance stall warning"?


PS.-- One interesting post few pages back was from a captain who made the point that sometimes having an alarm going of continuously can detract from an individuals ability to deal with a problem. I suspect there is a balance that has to be struck and I suspect / hope that the engineers, psychologists, pilots involved in cockpit design have already thought it through.

[Capt H Peacock]

I apologise in advance if this has been covered already, but in the absence of any trustworthy data, two buttons on the FMGC would have led them to the GPS altitude and groundspeed.

Used in conjunction with the unreliable airspeed drill, I could envisage a successful outcome to their predicament with a minimum of fuss.

On an antecedent note, don't mess with the ITCZ.

[edga23]

As I remember, the Air Caraibes pilots used GPS altitude to confirm that they were in stable flight using the pitch + power settings

[GerardC]

Concerning fuel on board. Please read BEA's report appendix 7 page 116/117.
http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf
At T/O, they had :
- 900 kg EXTRA fuel over the minimum M .82 DIRECT flight plan to CDG (alternate ORY) ;
- 1.900 kg EXTRA fuel over the minimum M .81 DIRECT flight plan to CDG (alternate ORY) ;
- 2.000 kg extra fuel over the minimum M .82 "subject to RIF to CDG" ("ETF" in BEA's wording) flight plan to BOD (alternate TLS).

At any given time, if fuel becomes an issue, the crew can decide to fly at M .81 (iso M .82) or to land at LIS/BOD/NTE without too much "embarrassment".

Concerning ITCZ crossing. Please read Tim Vasquez conclusion :
Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data

Air France Flight 447 crossed through an area of tropical showers and/or weak thunderstorms with weak to moderate updrafts and a high likelihood of turbulence. The flight penetrated one cell at about 0150 UTC and then entered a cluster of cells beginning at 0158 UTC. The suspected zone of strongest cells was reached at 0208 UTC, which corresponds with the beginning of a track deviation, and another cell appeared to be reached at 0210 UTC, which corresponded with the time of autopilot disconnect. The flight was suspected to be within areas of showers and precipitation up until the time of impact, and the descent below FL250 into the critical -10 to -20 deg C zone probably involved some degree of clear icing on control surfaces, though it is uncertain whether this affected recovery of the aircraft, especially due to the short accumulation time that would be involved.

Tropical storm complexes identical to or stronger than this one have probably been crossed hundreds or thousands of times over the years by other flights without serious incident, including ascents and descents through critical icing zones in tropical showers. My original conclusion from June 2011 is still unchanged: turbulence and possibly icing creating an initial problem that led to a failure cascade. Whether that final weak link was human or machine error is beyond my area of expertise and is best left for the experts at BEA.

If CB/turbulence was a factor, why did they start to deviate at 02:08 and not during the 01:50/02:08 period (when they went through an equally "bad" area according to figure 5b shown above) ?

Concerning captain behavior : he went to rest only 10 minutes before things went bad.
Who on earth would go to rest if the 160 Nm radar picture showed some "extra-ordinary" weather ahead

[RetiredF4]

Re AOA Probe balancing

Static Balance
Every AOA sensor I've seen on ground has been full stop down (neg AOA), which indicates no static balance. Don't believe I've ever seen one in flight.

I don't know a lot about AOA vanes, which I why I asked for someone really knowledgeable to speak up. You can peruse pix on airliners.net to get a good sample.

The F4 had an AOA probe without the need for balancing. During groundcheck we checked the free movement of the probe and it stayed where you put it.
AOA Probe

AOA value was displayed on the AOA gauge. The AOA also triggered an aural AOA tone in the headset, starting with a low frequency low repetitive tone at 15 units (if i remember correctly), becoming a steady medium frequency tone when optimum AOA was reached for landig (19.2 AOA) increasing to a high repetitive high frequency tone when AOA limits where exceeded. That was our stall warning and nothing else was needed.

AOA tone, at 50sec (Takeoff after wow, at 3:00 low approach, at 3:31 Fullstop landing

Advantage over the betty bitch thing is IMHO, that you are aware over the trend the AOA is developing, whether it is increasing or decreasing.

I´m not saying that this would be the ideal system, just to make a point that the balancing problem should not lead to shutting off any kind of stallwarning below a predetermined speed. The technology is available since 1960!

[Xeque]

Further to jcjeart's response (#1302) can someone tell me why trim is automatically triggered by nose-up or nose-down side stick commands in an Airbus? When flying my C152 I might wind in a bit of trim to ease the control loads when establishing a lengthy climb or descent but it's my decision. Once I've trimmed the aircraft for level flight I usually leave it alone regardless of altitude changes.

[jcjeant]

Hi,

Cause it's Airbus .. not Cessna ...
Can't more explain than this PDF

http://www.smartcockpit.com/data/pdf...t_Controls.pdf

And this:

[Xeque]

Many thanks. It will take me a while to read and assimilate Best wishes...

[zoomlens]

A couple of questions from an SLF

Apologies if these are dumb questions or have been answered before:

The BEA statement is silent on several points, presumably in order not to apportion any blame before publication of the main report in due course. One such omission is discussion of the crew's awareness of the approaching bad weather, and whether to change course. They did know they were heading towards an an area of turbulence before the captain went on his break at 01.55, but they did not decide to deviate. Would the two co-pilots have any indication after that that the storm was particularly severe? Would they have the authority to change course without consulting the captain? Would they be reluctant (more than, say a BA or Lufthansa crew) to wake him and ask to change course? Would these discussions be answered by the CVR?

[Mimpe]

THe Phantoms post a few pages back is a great summary. It sounds like a toxic mix of features that all came together in the worst possible way. The accident seems highly multi faceted, with a few major junctures to intervene ,all of which were missed. The thread has been immensely interesting. One of the most important investigations in aviation history.

Threats and errors not identified early ( aircraft design issues, flight execution) - altitude, weight, non deviation around significant dangerous weather , pitot failure, over complexity of automation and warnings ( including variation in flight Law,thrust automation, sensor and warning cut - ins and cut offs), likely significant deficiency in basic instrument scan/priorisation in the early phases of the emergency, spatial disorientation ( somatogravic- related to deceleration cues interpreted as nose down attitude), probable combined crew attention fixation AND distraction, cockpit design flaws ( sidesticks not visible to PNF, non linked controls) ,the least experienced PF the worst possible situation, non recognition of stall, seemingly simple problems with basic solutions interpreted in complex ways

Lots of little things snowballing . I only hope the final report pays full attention to every single one of the features of the accident - there appear to be so many contributing aspects.

[JamesT73J]

Quick question - seeing as Alpha seems to be one of the most important metrics of flight, where an instrument is available is it not possible for it to become the measure for things like approach speeds? I.e. consider Vref crosscheck etc but set approach against desired AOA number. After all this will be consistent across weights etc. Seems it would greatly help awareness and pilot confidence in what the wings are doing.

[Lonewolf_50]

If I may supplement what Retired F4 pointed out in re AoA indications in my response to Graybeard.
Graybeard

I don't know a lot about AOA vanes, which I why I asked for someone really knowledgeable to speak up

I don't think I am that much more knowlegable, but I am familiar with them on some aircraft.

The real measure of AOA is degrees, not knots, of course, although everybody has been shouting for a Stall Warning below 60 knots, not a specific AOA.

Not really. They've been arguing that clipping the stall warning in flight at 60 knots makes no sense. I agree.

IIRC, AoA is displayed in units, but that may be aircraft specific. For the Navy Trainers I am familiar with, T-45 stalls somewhere between 29 and 30 units, the T-34 at about 26 units AoA. See also Retired F4 comments above.

I don't have the numbers, but it appears that onset of stall of the A330 at that MAC and flap is less than 20 degrees.

OK

The report shows AF447 achieved AOA in excess of 40 degrees

Roger

How much AOA does it need to measure, 90 degrees, 120 degrees? What's the point?

To the point of stall, and beyond, as your barnyard theme suggests: let it weathervane in the airflow as it will.

You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system.

Yes about noise and distraction, but I see no reason to have a stall warning on the ground. There is an arbitrary decision to pick an airspeed. There is no reason to curtail it.

When you are flying, stall is about the most important thing to know about and unscrew first, since if you are in a stall, you aren't flying so much as falling.

Of all warnings, that ought to have primacy, don't you think?

Stall warning is not just another damn light or noise.

In fact, there was no doubt a point in the zoom climb to stall that airspeed was near zero, and the AOA vanes would fall with gravity, probably showing a negative AOA.

I don't agree with your assumption there. Airspeed near zero has little evidence to support it, and would have required IMO a much higher nose attitude than what FDR indicates.

I see no reason to clip AoA input based on any airspeed. That was my point. The WoW (squat?) switch would take care of the issue of spurious warnings, would it not?

AoA tied to stall warning would thus be tied to aircraft in flight/off the ground, which is where you both want and need stall warnings. It remains independent of the airspeed indicating system, as it should.

@bearfoil: I do not understand what you said regarding artificial horizon not being optioned by AF a couple of pages ago. There is one for each Pilot's Flying display, and a back up in the ISIS suite of instrumentation.

Can you elaborate?

[SaturnV]

GerardC.

We do not yet know what they saw on their radar display; that portion of the CVR where there may have been crew discussion of what was depicted on the display has not been publicly released.

We do know that a LH 744 preceding AF447 deviated by 10 NM, that an IB 340 at FL 370 and following by 12 minutes deviated by 30 NM, that an AF 330 following by 37 minutes initially deviated by 20 NM to the left of the track, and then 70 to 80 NM to the right of the track, and climbed from 350 to 370.

Vasquez estimates that the top of the Cb AF447 flew into was 56,000 feet. If a Cb of that size had been visible by daylight or moonlight, every pilot flying would avoid it.
____________________

I agree that possible fuel consumption resulting from a possible deviation was not a factor.

[FMY8036]

1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?

2. would a full down sidestick have had the authority to overcome the full up THS later on?

Those questions were already answered
It's YES for the 2 questions if the airplane was acting like it must be in alternate law
Pull up and the THS will go up
Pull down and the THS will go down

In the A320 Perpignan crash it seems that the sidestick couldn't overcome the fully deflected THS. How did you find out that in this case the pilots still had pitch control authority?

The report mentioned pitch down orders and the THS didn't seem to have moved.

Any clue about the THS position on the Afriqiyah A330 crashed in Tripoli?

[glhcarl]

Concerning captain behavior : he went to rest only 10 minutes before things went bad.
Who on earh would go to rest if the 160 Nm radar picture showed some "extra-ordinary" weather ahead

But even after the auto-pilot/auto-throttles dropped off it took several calls to the captain to get him back in the flight station? So how bad could the turbulence have been?

[willfly380]

Was the radar display on bright or was it left at full dim by mistake, hence maybe the 160/320 nm pic didnt show any Wx returns.These questions are difficult to answer.
When i was a senior F/O , I thought that i knew the radar like the back of my hand, only to relearn how to use it on my own as a captain.
There is [ in my opinion] some hesitation in deviating for Wx in many F/Os that i have worked with, Does not mean it applies to all.

[fgrieu]

THS position and flight law

jcjeant wrote

Two questions I could not find the answer to in this thread (bear with me if I overlooked them):
1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?
2. would a full down sidestick have had the authority to overcome the full up THS later on?

Those questions were already answered
It's YES for the 2 questions if the airplane was acting like it must be in alternate law
Pull up and the THS will go up
Pull down and the THS will go down

The BEA report tell us that the THS remained at 13% nose up including during the nose down stick input that occured during the descent, before 10000 ft. Therefore one (at least) of the following must hold true:
- THS movement under alternate law is more complex than suggested above; e.g. delayed, and the nose down command was shorter;
- the THS moved slightly but the BEA report does not mention it;
- flight law was not alternate law; direct? abnormal? sub-variant of alternate?
- there was a trim malfunction (but it seems unlikely that the BEA report does not mention it at this stage, so I rule this one out)

Any authoritative source on exactly how the autotrim works in the various flight laws?

[jcjeant]

Hi,

the nose down command was shorter;
- the THS moved slightly but the BEA report does not mention it;
- flight law was not alternate law; direct? abnormal? sub-variant of alternate?
- there was a trim malfunction (but it seems unlikely that the BEA report does not mention it at this stage, so I rule this one out)

flight law was not alternate law; direct? abnormal? sub-variant of alternate?
Sorry but if what you tell is right .. the PNF is an idiot !
In the BEA report PNF announce "Alternate law"

- the THS moved slightly but the BEA report does not mention it;

THS moved slightly but BEA does not mention it ?Can you explain (if BEA not mention it) how you know it moved ?

We can happily continue to speculate for months ... as the final report will maybe show next year ....

I can even speculate on the PF experience. ....
The PF experience as nothing to do with the accident .. it's not a reference.
Pilots on the Perpignan A320 XL crash had 7.000 hours and 5.500 hours on type ...
Teneriffe KLM B747 ... the best KLM pilot was PF