BOAC, re, "Airbus coming, Airbus coming", now that has made my day! ;-)

Thanks - I recall the event and had downloaded the AAIB Report of course.

On this particular entry into the conversation, it's not possible nor is it wise to take Bubbers' statements seriously. This is a Tech Forum: - There is much more to the problem, as evidenced in the AAIB Report.

The failure but primarily the humour in such suggestions for TCAS as made by Bubbers is, as the Report determines, the circumstances demand a far broader and perceptive comprehension of the problem at hand.

That we have an ATC system that is placing airplanes in closer proximity to one another purely for economic reasons is a major contributor to the issue. and the report makes observations on mitigating strategies. The critical statement in the Report which may lend the scent of credibility to an otherwise-humourous statement is, "Therefore, the RVSM safety case should not be driven by any assumption that a different crew might have contained the situation by making an earlier nose-down sidestick command than the A340 crew involved in this incident.". As John Smith correctly observes, it is not an Airbus-specific problem and as such requires serious and imaginative solutions to deal with the problems that financial considerations and not safety considerations have created. That is happening, as stated in the Report, though glacially, as these things do.

DonH - while not wishing to keep on clapping my hands to keep the damn Oozlum bird flying, surely it is equally an 'onus' on any crew, knowing the existing reduced seperation, to add to John S's simple doctrine "I must try not to climb or descend into/through another aircraft's level". Hence the 447 PNF should have been 'screaming' to PF about the excursion in no uncertain terms and taking control if necessary?

A question from a glider pilot, if you professionals would be kind enough to inform me:

In the A330/A340 incident, there was a sudden increase in what glider pilots call total energy - the sum of kinetic (speed) and potential energy (altitude). Presumably this was caused by windshear, or rising air (wave or whatever) caused by the nearby jetstream or front. In gliding, if the energy increase is not wanted, we counteract the increase by spilling it – with increased drag (e.g. airbrakes) or letting the speed bleed off gradually should circumstances permit.

It sounds as if they had only two quick choices, since power reduction would be slow – climb, or go into overspeed. Is that right? If climb is too dangerous leading to a level bust, can overspeed temporarily be tolerated? Or could drag be increased (airbrakes?)?

Overspeed protection.
 

Bubbers:
Bloggs:
BOAC:
" or a B777/B787. "


http://i474.photobucket.com/albums/r...psdb5bad00.jpg

OH DEAR OH DEAR OH DEAR ! ! ! !

Now Mr Boeing has done down the zoom-climb route to solve a kinetic energy problem.

The inmates really are running the asylum and having the keys to the pharmacy as well they've gone on one helluva trip?!!

Gawd help us airframe drivers and the hapless SLF! :ugh:

chrisN,

From another glider pilot, also an ex-professional though not as a pilot,

Yes, there was an overspeed condition that caused a warning an disconnection of the A/P. However, that overspeed condition was very brief and not really a problem. Shortly after that the airplane encountered a vertical gust that increased the AoA to alpha-prot and put the FCS in high-AoA protection mode which caused the zoom climb.

HN39, Thanks.

Yes, agree, the Airbus UAS drill, as still published, can be confusing. However, numerous Airbus publications available on the web indicate how the UAS drill and QRH checklist were, and are to be handled and the FCTM notes do reflect this although they could be much clearer still.

Earlier in this thread I pointed out where in the original (now closed) threads that this discussion began taking place. However, if some comments here are an indication of the broader piloting community, then, without blaming anyone as to why this may be so, there remains a great deal of misunderstanding on when and how to apply the memorized drill and when not to and instead proceed directly to the QRH checklist items. In fact, the memorized drill and the checklist are NOT sequential, they are an "if/then" decision point.

First, when loss of airspeed information occurrs, the qualifying condition, "If the safe conduct the flight is affected" is not clearly defined in the drill-checklist, nor is it defined in the Boeing checklist, (there are no memorized items or initial pitch-thrust memorized combinations in the B767/B777 UAS responses). The drill-checklist is not a sequential drill - rather, the "safe conduct of the flight affected" is a primary "if-then" decision point in the UAS response - the safety of the flight IS affected at takeoff, initial climb or descent/approach/landing.

Loss of airspeed information at cruise altitude is not an emergency and because the airplane is, for all intents, stable in pitch and power, then "nothing" needs to be done (except keep the airplane stable), because the safe conduct of the flight is not affected, (in comparison to the takeoff/landing case). The crew, (PF) assumes control of the airplane to maintain aircraft stability by maintaining thrust and pitch at current settings, (Aviate), maintains/alters heading as required, (Navigate) and calls for the ECAM actions, (Communicate), to be done followed by getting out the QRH Checklist to set pitch and power for the remainder of the cruise.

The graphic below illustrates this and I think this is the source of much of the confusion:

http://batcave1.smugmug.com/photos/i...-kXr5vDx-L.jpg

The "Pitch/Thrust settings for initial level off" are just below this point in the drill. The balance of the QRH provides pitch and thrust settings for varying weights in cruise, descent, approach, landing and go-around. However, in all cases of a UAS event in cruise, airspeed indications returned within about one minute, including AF447's airspeed indications, but the stall had been entered by that time.
Yes. This is the way the drill & checklist were always intended to be done. Airbus stated as much in its December, 2007 "Safety First" magazine (pg 14): in the oft-quoted-in-original-threads Joelle Barthes article entitled, "Unreliable Speed":
followed by the a graphic, describing what is intended by the above:


http://batcave1.smugmug.com/photos/i...-65CQmXw-M.jpg
- Safety First magazine, December, 2007, Joella Barthes

In fact, in an Airbus presentation in September 2006, it is clearly stated that what constitutes "safe conduct affected" is defined in training:

http://batcave1.smugmug.com/photos/i...-xMfgFdR-M.jpg
Airbus OLM FBW 2006, (Unreliable Speed) - Toulouse - 23-28 September 2006

In my opinion and from what I have researched for a long time now, the UAS response is NOT a sequential drill-checklist - never was.

What is confusing about this is not entirely nor necessarily the Airbus UAS drill and checklist. The large black dot is a decision-point, not a "start here and follow all items" point. Buy down below, the "Level Off..." action item has the same black dot, making the drill-checklist appear "sequential". It is not.

A large part of the problem is knowing the way checklists are written in terms of these "decision points" and the meaning of correct indentations, (which this drill-checklist appears to not have). The decision point regarding safe-conduct-of-the-flight-affected permits/requires that the crew either execute the memorized items OR, (in cruise for example), they do the QRH checklist after stabilizing the aircraft in level flight.

This has all been reviewed and discussed in the original threads (part of which has been pointed out but, I assume, not viewed or referenced by some in the present thread.

Hi BOAC;
No worries BOAC - I think we're all clapping in unison!

Yes, agree with you entirely - this goes to the "giving in to automation / not understanding one's airplane / maintaining situational awareness" discussion though. Solutions, offered in the AAIB Report, suggest that among a few, offsets may be routinely considered. Here's one reason why - he's 2000ft above. And I've been hit by wake turbulence from a B744 1000ft above, opposite direction as we passed right under him - very sharp, 20deg roll, then nothing.

http://batcave1.smugmug.com/photos/i...-fx3zxH4-L.jpg

Thanks DonH, that was what I trying to tell him but not as clearly as you put it. I'm not going to bring the subject up with him again because I will just be the idiot again.

Hi Bubbers;
, Yes, probably best to let it be. There will always be, 'yeah, but's...'

These are Airbus' own documents, available on the web - I just did a lot of research over time because I remember being confused about the drill myself when doing the initial training from Boeing to Airbus equipment.

And, I like to keep the tech topic on topic!

DonH - "And, I like to keep the tech topic on topic! " - agreed, but unfortunately 447 opens a large can of worms. Whether the 'automatics' brigade like it or not, some of the programmed features of the AB system contributed to both 447 and the 330/340 events. Note I say 'contributed to' and not 'caused'. Autotrim and the 'software' decision to abandon the stall warning did not help 447 or the 330/340 - why? These features are good features and have useful functions in many situations BUT they can cause problems where they should not, and the training is inadequate in 'teaching' crews to defer to the automatics. There were, after all, two hopefully sentient beings in the cockpit who could have decided how to handle an overspeed without having HAL do it for them. Now apparently Boeing are going the same way (with overspeed) - again why?

On the topic of the UAS checklist, we have unfortunately 'lost' the on-going most valuable inputs from PJ2 due to bizarre modding, but it is well worth searching his posts on the topic on the 447 threads. Again, in both 'events', we have crews without the 'big picture' and mesmerised like the proverbial rabbit by the systems.

I have, along with others, for a long time advocated a major change in training for the 'glass/auto' environment. BA recognised it years ago (late 20th century) with their short 'don't get mesmerised' ('EOI') course. The increasing lack of real experience in cockpits plus the over reliance on highly seductive systems is taking us down a clearly defined one-way street. There are some side street exits, but we are running out of them.

DonH
I have the documents you have quoted and I am in agreement. However the real problem was I think UAS was not considered seriously as a possibilty as let's say an engine failure. During type rating it is conducted only as a DEMO in after takeoff scenario. I am not sure if it is ever practiced threafter. It is not in regulatory tick boxes. Recognition of UAS can be quite confusing and if you are confused or ignorant of the procedure then anything can happen. Even 757 has crashed before.

During type rating it is conducted only as a DEMO in after takeoff scenario

I'm a tad out of touch with the training game these days but some of us used to make it a private requirement using spare time during an endorsement to ensure that pilots could handle several of the unlikely but very high risk scenarios.

For me and several of my colleagues in a previous life that included a total (or as close as we could make it in the particular sim) loss of pressure readouts - low vis takeoff with a single pilot no help recovery via an ILS to minimums.

It goes without saying that included no FMS, FD, etc. Realish sim flying.

Allowed us to sleep well at night.

Gotta go with BOAC.

I also wonder how AoA protection laws could have caused a climb as 'nuts suggests.

The various factors resulting in the crash are all worthy of discussion and some "learning", IMHO. CRM, flight control laws, aircraft performance, instrument/sensor failures, basic piloting skills, and the beat goes on.

I can tell you that 34 years ago we all learned a lot that wasn't in the "books" and had not been exposed to us in the sim ( we didn't have a sim for 3 years after becoming operational, heh heh). Our control laws were primitive compared to the 'bus, mainly due to only two autopilot modes that worked with the FLCS. And of course, our operational requirements demanded flying to the limits, personal and aircraft. Nevertheless, we all learned a lot and we passed on lessons to the next generation and the one after that. Now, I am here trying to contribute something for you heavy dudes to think about. And you must realize that CRM is foreign to me. Only crewed jet I flew only had one set of controls and the guy in the back seat was a "systems operator".

Don't discount the fact that the autopilot is still available with a loss of IAS. There is a selected Pitch Damp mode that the pilot can select to maintain attitude if desired. Options are nice.

I maintain that if AF447 were flying an aircraft with an operable autopilot during a loss of IAS, the airplane would still be flying today and all the folks would be alive. Another nice option.

The question of why such a sophisticated airplane could trip the autopilot with a loss of IAS and abandon the automation dependent crew has yet to be answered.

Or from the other side of looking at this how about we make the crews not automation dependent?

Hi Gums,
I believe Alpha Floor was triggered (at a certain Alpha threshold). The thrust goes to TOGA power despite the TLs being somewhere else. With no side stick input, the aircraft will then maintain Alpha Prot angle of attack.

All that was required was a side stick input to maintain current FL and disengage Auto Thrust.

To protect against over speed, L1011 - 500 had RSB (recovery speed brake). Full speed brakes were automatically deployed and had to be manually stowed.
PFM.

A340 Zoom-Climb and AIRPROX with A330
 

Quote from HN39:
Yes, there was an overspeed condition that caused a warning an disconnection of the A/P. However, that overspeed condition was very brief and not really a problem. Shortly after that the airplane encountered a vertical gust that increased the AoA to alpha-prot and put the FCS in high-AoA protection mode which caused the zoom climb.

Yes, and I've always been curious about the implementation (in pitch) of AoA Protection Law ("Alpha Prot"), which can only happen if the AP is off (caused here by the windshear-induced overspeed). Clearly it is advantageous to stop the AoA increasing unless the pilot commands such by "pulling" the sidestick (aft of neutral). The bit I don't understand is why the FBW is programmed to maintain Alpha Prot even if normal-G exceeds 1 (I'm referring to the situation at cruise speeds; not low speeds). To put it another way: on the face of it, it seems bizarre for the FBW to "grab" a transient, higher-than-normal AoA even if it results in more than 1G with a neutral sidestick (assuming wings level). No doubt there are good reasons for doing so - perhaps the likes of OwainGlyndwr may explain? ;)

In this case, the AAIB and AI decided that a "phase advanced" value of AoA - caused by a vertical gust - triggered Alpha Prot Law (mode). "Phase advanced" means that the AoA was rising rapidly, and going into Alpha Prot Law was a pre-emptive move (as-per stall protection systems, including stick-shakers, on old a/c like the BAC 1-11 and VC10). Once the FBW system has engaged in Alpha Prot, the AoA presumably rises further to the stable value of Alpha Prot. If so, that would further exacerbate the situation in this particular scenario. Forward (down) sidestick is ncessary to restore Pitch-Normal Law. (Does anyone know how much?)

There is no message to inform the crew of the change of the Pitch Law (mode). In this case, attempts to re-engage the AP seem to have caused the delay in sidestick intervention by the PF.

BTW, in the AAIB's DFDR trace, the sidestick parameter seems to give negative values for "up" inputs, i.e., stick back.

The common factor this incident had with the much later AF447 accident is that of the unexpected transition from automatics to "manual": specifically from AP to FBW, in a pitch law other than Normal. In this AIRPROX case, the FBW system forced the a/c into an undesired zoom-climb which needed positive crew intervention to counter. In AF447, the FBW made no such input; the PF forcing the a/c into a zoom-climb by inappropriate sidestick inputs.

Desert185,
Don't discount the fact that the autopilot is still available with a loss of IAS. There is a selected Pitch Damp mode that the pilot can select to maintain attitude if desired. Options are nice.

We had APs with pitch wheels a bit like that on the B707 and other types of the 1960s and 70s, used to select pitch in climb and descent, plus a "height" (ALT) lock. Not sure if the ALT lock tripped with loss of IAS - probably not. On Airbus FBW, tripping the AP is normally a non-event, because the FBW effectively holds the current attitude at least as well (initially).

bubbers44,

Are you saying the Tristar airbrakes do not retract themselves automatically after the aoverspeed? And does the lever move to reflect their extension?