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-   -   AF 447 Thread No. 10 (https://www.pprune.org/tech-log/493472-af-447-thread-no-10-a.html)

Lonewolf_50 14th Sep 2012 12:06


Gums, "nugget" is not a terribly professional term...
Lyman, given how much stick and rudder time your average long haul pilot seems to get, "nugget" seems most appropriate, particularly when you consider that gums speaks from the PoV of a single seat, stick and rudder kind of pilot. ;)

In the Navy, nugget used to refer to one of our squadron pilots who had yet to complete an operational deployment with an aircraft, or to otherwise have low time in model.

We were all nuggets, once ...

Lyman 14th Sep 2012 13:57

LoneWolf

Noted. My sense is that it is presumptuous, that a term like nugget is demeaning, and serves in the long run to cement a conclusion that may not be accurate, that the PF was some kind of flustered 'rookie'.

It may have happened that way, but public opinion is wildly vunerable to myth fabricated over time in the media.

My case, in point.

RR_NDB 14th Sep 2012 14:39

Important input(s) to System
 
Hi,

CONF iture:


This could be a serious help to the crew to understand what's happening and switch to the appropriate procedure.


Any input (to the System) capable to promote important changes in A/C must be informed in real time and clearly to PF.

This is safer, much better than wait a complex System process it and present itīs output(s).

Airbus SAS philosophy relies on System to do this as the Design group paper (mentioned in earlier post) emphasizes.


Bandwidth (System) limitations. No problem: Implement an UAS (simple) device (retrofit).

Question: Pitotīs (and ADR) subsystems would be compatible?

Lyman 14th Sep 2012 14:49

On a basic level, perhaps a more critical look at the parameters of autopilot in Turbulence? Any situation which presents as requiring manual handling should originate a loss of autopilot and reversion to manual flight. Not only UAS.

We here have consistently exonerated the use of Autopilot in this turbulence.

The pilots admitted they were entering cloud, but more important is the assumed icing up of all three pitots. Of course they were in cloud.

Cool Guys 14th Sep 2012 15:01

Hey gums, I love your posts. I have to smile every time I read one. Don’t know why the couple of boisterous non pilots here have to push their opinion so much.

Truth is relative, what is real to you may not be to others.

OK465 14th Sep 2012 18:22


I have not read the BEA mentioning the NAV IAS DISCREPANCY ecam msg ... did I miss it ?
CONF:

This is a good question.

From observation, this ECAM message will only appear if there is a 'single source' discrepany between the two displayed airspeeds. In other words, you're looking at, for example, one PFD at 250K and the other at 200K. One ADR output is erroneous and the message is providing info much in the same manner as the old 'instrument comparators' did. Something's displayed wrong here, you guys check it out.

With the displayed speeds sourced normally from ADR's 1 & 2, an erroneous output from ADR 1 OR ADR 2 (not both) will result in this message (10 second delay). (Conversely, if the problem is with ADR 3 and it is not switched, you won't see this message unless you had a reason to transfer either side to ADR 3.)

Once you get 'multiple' discrepancies (i.e. 2 or 3 ADR's), the message 'downgrades' to the ADR DISAGREE status.

What's interesting is...if this is done in sequence, 1 ADR and corresponding IAS DISCREPANCY, later followed by multiple ADR's and resulting ADR DISAGREE message, the IAS DISCREPANCY message is dropped out of the ECAM string permanently (not recallable), leaving only the ADR DISAGREE actions.

If you have simultaneous ADR problems (within 10 seconds), the ECAM jumps right to ADR DISAGREE & bypasses the IAS DISCREPANCY message completely, which may have been the case here.

With respect to the timing associated with ADR DISAGREE in the report, I recall someone saying in one of the much earlier threads that the times associated with the downlinks were not necessarily the actual times of the message appearance, but I could be wrong about this.

gums 14th Sep 2012 20:54

Nuggets and newbies and dweebs and...
 
Sorry if I offended any of the real pilots here.

Wolf has it right, and USAF called the newbies "Joe Baggodonuts", heh heh. The term "dweebs" had not been invented yet.

I adopted the term "nugget" due to my connections with Nasal Radiators way back then. It is used for the junior pilot or nav until he's in the other seat. No big deal, and the PF on AF447 was the most junior troop. 'nuf said.

All of we pilots were nuggets or less flattering descriptions in the beginning. We learned and we matured and we did just fine or wound up a smoking hole. Some great mentors led us, and we had the benefit of them along the way. Wouldn't be here today if not for them.

gums 14th Sep 2012 21:05

distant galaxy, far, far away
 
Re: The Viper and memories of a distant universe


a private message reply to another member of our group after I got his post.

Video of a Viper flight included from my private message, and then one of my own.

PLZ note the tiny stick movements, so I guess that 1/8th inch shows up some of the time, heh heh.


My reply to a member.....

Thank you xxxxx

Brought back many memories of that neat little jet ( first FBW, and look at stick movements on a replay).

New oxygen connects and the helmet display for off-boresight aiming of the missiles and A-2-ground tgt acquisition, etc.. Whew!

Note the lack of lag when the dude relaxes pressure on the stick.

Think that we had all that back in the late 1970's, and only FBW accidents were related to the power supplies to the confusers.

The thing was magic, and although I had doubts about all the "protections", I became a believer very quickly. They never gave up, and we always had "something" left, even if pitots went FUBAR, and so forth. Not like AF447.

Unlike the 'bus and the Boeing designs, we had zero mechanical connections except to the blow down bottle for nose gear and the throttle cable to the motor. Even the family model did not have mechanical conections to the stick that Joe Baggodonuts was using.

Was a great time, and was blessed to participate.

For viewing enjoyment, try this sucker using Quicktime or Final Media Viewer of my leading edge flap failure landing.

http://www.sluf.org/warbirds/lef-landing.m4v

thanks for the nice words...

infrequentflyer789 15th Sep 2012 00:27


Originally Posted by CONF iture (Post 7409086)
It is not what the CVR tells.

In between your PF "gap" though, PNF says in one sentence: "on a
perdu les les les vitesses". Almost reads to me like PNF is completing PF's sentence which PF then confirms. PNF definitely knows and states it.


If the guys knew, why the PNF would have said :
Fais attention ā ta vitesse - Fais attention ā ta vitesse
But then why is the PF response to that "okay, okay okay je redescends". That line makes no sense to me - maybe PF was saying speed but pointing at altitude :confused:



As the BEA attributes to the NAV ADR DISAGREE ECAM MSG the first priority after the AUTO FLT AP OFF, why that message did show up only 2 minutes later ?
ADR and IAS disagree have been discussed before - both require specific sequences of events to trigger and not every UAS matches that pattern. See e.g. http://www.pprune.org/6597470-post730.html and http://www.pprune.org/tech-log/45687...ml#post6592148 but also worth google searching tech-log - there are many more.

IAS disagree might not have been installed on the a/c.

I would expect BEA to comment on any message that should show up but did not, and why any message did show up. Not sure we can expect comment on every message that did not show up because conditions were not met, or any system that wasn't installed - report would be 1000s of pages.

BEA don't comment on BUSS either (like IAS disagree, they don't even tell us if it was installed or not). We know AF didn't take BUSS option, I've seen rumours (maybe here) that they thought it wasn't any good ("useless" above FL26) - but maybe it was just the $$$. Either way, BUSS would in fact have made a difference to the sequence of events - but is not mentioned by BEA because they deal with what was on the a/c, not what could have been.

CONF iture 15th Sep 2012 03:36

Thanks for the explanation OK365.

What I find disturbing is that the system takes the decision to disconnect the AP and switch to ALT LAW based on its analysis of the ADRs outputs but does not think as necessary to keep the crew informed about the reason it took that very decision ?

With respect to the timing associated with ADR DISAGREE in the report, I recall someone saying in one of the much earlier threads that the times associated with the downlinks were not necessarily the actual times of the message appearance, but I could be wrong about this.
P97 on the Final Report specifies that the NAV ADR DISAGREE ecam msg did appear only at time 02:12:44

IMO it was not related anymore to the initial conditions of UAS, but most probably to the latest flight conditions with high AoA and changing bank, all of it playing on the different probes and sensors.

CONF iture 15th Sep 2012 03:42


Originally Posted by IF789
In between your PF "gap" though, PNF says in one sentence: "on a perdu les les les vitesses". Almost reads to me like PNF is completing PF's sentence which PF then confirms. PNF definitely knows and states it.

But "on a perdu les les les vitesses" is more probably related to the disappearance of some speed symbols and is not a positive indication of UAS.


But then why is the PF response to that "okay, okay okay je redescends". That line makes no sense to me - maybe PF was saying speed but pointing at altitude
Because the PF was conscious that he had gained altitude which was detrimental to the speed. He did agree to go back down, but never took the necessary attitude to do so …
IMO they have never understand their initial problem and the reason for the AP A/THR DISC was a case of UAS.
Thanks for the links on the previous threads.


report would be 1000s of pages
It is not a good reason.
Remember, the accident is a consequence of a scenario of UAS initially, so it is imperative for the BEA to develop comment and analyze anything related to that matter. Of course NAV IAS DISCREPANCY ECAM MSG or the BUSS function have to be mentioned. It would require 10 pages at most not 800.


We know AF didn't take BUSS option, I've seen rumours (maybe here) that they thought it wasn't any good ("useless" above FL26)
By procedure the BUSS is not to be used above 25000 feet.
IMO that equipment for AF447 would not have done the slightest difference to the outcome.

UNCTUOUS 15th Sep 2012 05:01

Time for a bit of "In Your Face" Technology
 
When abstract and abstruse technology runs amok, it needs to be immediately apparent to a flight crew that anything (or everything?) in technoville is becoming unstuck.... or even just on its way out. Fortunately there is (prospectively) a digital way to do that - to "in your face" alert the crew of an imminent GIGO fiasco (GIGO = garbage in/ Garbage out). But more on that in a moment.....

Firstly it always helps to have the captain on the flight deck when faced with the need to intervene manually or interpret some confusing happenstance. It also tends to offload the cruise captain/F.O. and his oppo of the need to resolve any differences of opinion about what to do next. Solution? A klaxon in the captain's crew rest area would tend to galvanize el capitano into instant action. His prompt appearance on the flight deck would serve to defuse the always prevailing angst and uncertainty about actually making an assertive decision - possibly one that properly lies solely in the province of command. Acting resolutely and taking the initiative is laudable when success is the outcome. However when it isn't, it can often be career-shattering. Such is the nature of Monday morning quarter-backing aided by 20:20 hindsight. The fluster factor quotient in a two F/O cruise crew is the facade that lurks. Sudden exposure to an AF447 like scenario can freeze-frame cross-cockpit communications and comprehension. You need a licenced decision-maker on scene. That's what command is all about.

I honestly don't know how a captain can achieve slumber in any situation where two underlings are left to their own devices. It's not about trust, it's more about insecurity. I can recall springing out of an aft bunk and dashing to the flight-station in an Orion because my wakening nightmare had been that we were spinning into the ocean a few thousand feet below. The fact that we were asymmetric and hanging off the three props at endurance speed had a lot to do with my subconscious mindset. We were loiter surveilling a yacht full of drugs enroute to some unknown landfall. Of course, when I burst into the cockpit nothing was happening, yet I've relived that nightmare quite a few times.

So, what to do when the autopilot disconnects suddenly and the beast requires someone to instantly grab the reins? It's never totally apparent WTF is actually happening - what's trustworthy? what's possibly erroneous? what's the state of our automation modality? what's clearly failed? and most importantly, where to next with the trouble-shooting checklist? - particularly when the failure is epicentric and tentacular. The omnibus checklist series that covers all contingencies is yet to be written. Even if it was "to hand", it's never going to just flop open at the page you want. A noisome background of alarms and a panel covered with non-specific warnings serves only to alarm - the alert has already happened.

Failure of a pitot feed or an AoA vane are two exemplars that spring to mind. Reflect upon the accident to 5Y-BEN, an A310 that dropped into the ocean just off the end of the runway at Abidjan. There'd been prior instances elsewhere of the same nasty affliction that that flight-crew faced, a stick-shaker after take-off that just wouldn't stop - and a crew that responded
"properly" by unloading to avoid an imminent stall - but unfortunately terminating their trouble-shooting at sea-level. It appears that some ramp-rash to the AoA vane on the tarmac had gone unreported and went unnoticed on the walk-around.... so the stick-shaker was bogus. But whatever the cause, it's always the instantly apparent "cure" that's linked to a happy outcome.

Statistically, a perplexed crew is around 50% unlikely to come up with a workable solution when suddenly faced with "the unstraightforward". What to do about that?

One of the happier and fortunate aspects of our digitalis era is the ability to include self-check and to clearly report any discrepancies with specificity. BITE (built-in test equipment checks) has been around for decades, but it's normally restricted to a confession to a master warning system that it's not feeling "up to snuff" - and the alert that's forthcoming is always/usually preflight (only) or if inflight, too abstract for direct intervention. It needs time-consuming troubleshooting to some extent. That's where an "in your face" alerts system could step in to fill that conceptual breach. There's nothing like clarity in failure - to point the way forward. An FAQ reference is just not an option once that 4th dimension (time) is in play.

The evident need is always to minimize trouble-shooting. Just saying "aviate, navigate, communicate" is no salve for system self-expression in automation. Automation to date has been designed to alleviate the normal workload. Its next generation and obvious development challenge is to relieve the abnormal workload.

Rather than just "blacking out", it would (IMHO) be infinitely better for a suddenly unreliable instrument or screen to either:
a. show on its face a clear exposition of its failure status (or of faulty input data being out of limits).. or...
b. simply show vertical or horizontal raster (think of the older analogue screens with a faulty vertical hold) - i.e. its "out of action" status.
Just flickering or failing to zero or displaying a false reading or even an unobvious non-annunciating OFF flag is wholly unacceptable - but that's exactly where we are "at" now.

Some failures just lead to a querulous FAQ of WTF (aka: "what's it doing now?"). Some indicators (such as airspeed tape displays instead of round gauges) are just not attention-getting enough.

Digital has always been an infinite resource for safer flight. Its exploitation needs to now include some deeper systemic introspection and a non-misleading advisory capacity. Silently changing flight modes is an insidious deception. Low-side stall warning re-triggers on an attempted exit from a deep-stall condition? There's nothing simplex about that. It's a duplicitous behaviour..... and one that befuddles any human thought process.

Developments in avionics systems now needs to concentrate upon
the human interface. A last-ditch fallback to manual flight is necessary. But it seems to be more akin to falling backwards into a cold pool of uncertainty surrounded by undefined but obviously present further failure-threats. A clean-break reversion to a manual flight mode whose parameters and limits are familiar? That's the way to go.

john_tullamarine 15th Sep 2012 05:53

I think that your generalisation regarding F/Os is unreasonable but very important in the context of this series of threads.

An half competent, reasonably experienced, F/O ought to be quite capable of addressing any abnormality in the absence of the commander .. else he/she is going to experience great grief during upgrade training.

I am reminded of an old story about a DC3 droning its way from the mainland to Tassie .. or perhaps, vice-versa .. the tale was related to me many years ago..

The legendary Jason H, as normal ops would dictate, was soundly asleep whilst my mate Baz was minding the shop. As luck would happen one noise source ceased making its din and Baz proceeded to do that which was required. Jas woke up due to the change in noise, observed that all was well and under control ... commented "carry on" ... and returned, forthwith, to the land of nod.

Baz recovered the aircraft in the usual manner and life proceeded.

However, there is the underlying presumption that an F/O must be competent and capable ... some of us are wondering whether that tenet was lost somewhere in the transition to automatics upon automatics ?

RR_NDB 15th Sep 2012 06:49

"In Your Face" Technology
 
Hi,

UNCTUOUS:


... - to "in your face" alert the crew of an imminent GIGO fiasco (GIGO = garbage in/ Garbage out)




You need a licenced decision-maker on scene.


Capable to understand precisely and fast whatīs going on. What requires a lot of multidisciplinary knowledge. Training is enough?


- particularly when the failure is epicentric and tentacular. The omnibus checklist series that covers all contingencies is yet to be written.


:ok:


Statistically, a perplexed crew is around 50% unlikely to come up with a workable solution when suddenly faced with "the unstraightforward".
So, SURPRISES to the crew must be reduced to a minimum. Why not to ALERT CREW IMMEDIATELY when the System will face UAS? This is particularly important because there are risks of GIGO.


The evident need is always to minimize trouble-shooting...Automation to date has been designed to alleviate the normal workload. Its next generation and obvious development challenge is to relieve the abnormal workload.
Congratulations! I was concerned with all this when started this Thread:

Man-machine interface and anomalies
The increasing technological sophistication in FBW planes brings benefits and challenges to the pilots and other 'players". The objective here is to discuss the "interface" and itīs components, specially when facing anomalies.



Rather than just "blacking out", it would (IMHO) be infinitely better for a suddenly unreliable instrument or screen to either:
a. show on its face a clear exposition of its failure status (or of faulty input data being out of limits).. or...
b. simply show vertical or horizontal raster (think of the older analogue screens with a faulty vertical hold) - i.e. its "out of action" status.
Just flickering or failing to zero or displaying a false reading or even an unobvious non-annunciating OFF flag is wholly unacceptable - but that's exactly where we are "at" now.
:ok:


Its exploitation needs to now include some deeper systemic introspection and a non-misleading advisory capacity.
:ok: (Bold mine)


Developments in avionics systems now needs to concentrate upon
the human interface.
R&D, a complex one, is required.


That's the way to go.
I agree completely!

Thanks for excellent post!

TTex600 15th Sep 2012 14:27


Originally Posted by UNCTUOUS

The evident need is always to minimize trouble-shooting. Just saying "aviate, navigate, communicate" is no salve for system self-expression in automation. Automation to date has been designed to alleviate the normal workload. Its next generation and obvious development challenge is to relieve the abnormal workload.

Dam#%# , I wish I'd written that. EXCELLENT, EXCELLENT point Sir!

The best I ever came up with is that the bus helps me doing things that I can do well already, but is of little use when things go wrong.

Excellent post.

Lyman 15th Sep 2012 15:54

"The best I ever came up with is that the bus helps me doing things that I can do well already, but is of little use when things go wrong."

My point from the outset. A genIII autopilot. Nothing wrong with that, if everybody, including the pilots, is totally conversant with the way it uncouples. And the ways it behaves in 'uncoupled' flight.

From the length of the thread, and the number of posts from those who fly it, and those who designed it, and their disagreements to this day,

Not so much.

gums 16th Sep 2012 15:02

reduce workload or become a "monitor"
 
great attitude, Tex


The best I ever came up with is that the bus helps me doing things that I can do well already, but is of little use when things go wrong.
Make no mistake, folks here, we single-seaters used the A/P, but we used it to reduce workload and not sit there and "monitor". So I flew almost 2,000 hours in a jets without an A/P, and another 1,500 with a nice A/P, and maybe another 600 with really good A/P features ( mach hold, coupled ILS approaches, even turns directed by GCI to find a target). The big thing was I never used the sucker as a routine way of doing business except on long flights and at constant altitude/heading. Gotta tellya that in crappy weather, and diverting to another field, that the A/P allowed us to find the new approach plate, change IFF, coordinate with wingman, etc. Still had to "monitor", but we didn't have all the cosmic FMS that helps ( but still turns the wrong way as in the Cali accident).

As Tex has opined, the sucker is great for normal ops, but sucks when things go awry. Hell, my Shuttle buddies used the A/P until hitting the heading alignment circle. First 15 or so minutes was 'cause the A/P was faster than them and followed the prescribed trajectory more accurately. I can understand that. But I will guarantee those guys could have followed a good flight director all the way down.

Only HAL help we had in the Viper was when AoA got above 29 or 30 degrees, and then it helped with directional control to keep us outta a spin. Unfortunately, our cee gee was so far aft that all that resulted was settling into the classic "deep stall", heh heh.

Guess it's just a frame of mind for many of us here, but I have grave feelings about simply becoming a "monitor" versus being a "pilot".

CONF iture 18th Sep 2012 13:26

DIR LAW
 
To expand on that one according to the A330 FCOM it is possible to trigger DIR LAW through a TRIPLE PRIM FAIL which allows BOTH SEC still in operation.

TTex600 18th Sep 2012 15:00


Originally Posted by CONF_iture
DIR LAW
To expand on that one according to the A330 FCOM it is possible to trigger DIR LAW through a TRIPLE PRIM FAIL which allows BOTH SEC still in operation.

The question is then, what will the aircraft control response be with only spoilers for roll control? Or do the SEC's give aileron control in the 330? I confess, I've gotten lazy and haven't looked up the answer.

My original point was this, it's dam#$%^$ near impossible for a sim instructor to configure a sim in a way to force direct law without also removing control surfaces from the pilots usage. And therefore it's quite difficult for a pilot to experience true direct law in the training environment.

OK465 18th Sep 2012 17:37


Or do the SEC's give aileron control in the 330?
Yes.

(With only 1 SEC you retain same aileron control as with 2 SEC's when flaps are up, but when flaps are down you lose one outboard aileron with only 1 SEC)


I've gotten lazy and haven't looked up the answer
Real question is, 'where would you find it?'.


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