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Mansfield
5th Aug 2010, 04:07
I just returned from three days in Toronto participating in the loss of control sessions at AIAA. There were about twenty-five presentations. Unfortunately there is no transcript, so-to-speak, as all presentations are based on published papers that AIAA sells.

Both Boeing and Airbus discussed the LOC issue, and they emphasized their collaboration and agreement on the fundamentals. The role of fully stalled airplanes in LOC was discussed extensively, and both manufacturers would like to see the “power-out” stall recovery eliminated. Rather, the recovery must incorporate a positive reduction in AoA before adding power. BOAC will be happy to know that the issue of the aircraft being fully trimmed just before the stall is well understood by all. Airbus pointed out that an aircraft trimmed nose up into the stall may not have enough elevator authority, with full power added, to lower the nose at all. Dave Carbaugh from Boeing pointed out that their general data, just like my icing specific data, shows a very common propensity to pull on the column when faced with stall or upset conditions. The Colgan captain was by no means the only guy to behave this way.

Both manufacturers stressed that large jet aircraft are laterally unstable while stalled, and the ailerons are most likely ineffective. However, before we slide down the slippery slope of rudder usage during stall recovery, I should point out that the manufacturers emphasize that before anything else, the wing must be unloaded, AoA reduced, flow reattached and then the ailerons will unroll the situation just fine.

Airbus also pointed out that there were almost no situations that require immediate action…there is usually a few seconds available to think it through before whomping on the controls. Their point was to get the response right before initiating action. Not unreasonably, they felt obligated to run wake turbulence up the flagpole, pointing out that this type of encounter would probably not require an immediate response.

There was also a lot of discussion about simulation, how to improve it, and the general inability of a typical hexapod simulator to get the job done.

As regards Don Bateman, he has a number of great ideas, and emphasized the need to do what can be done without hardware development. For example, he pointed out that a simple code change will allow the EGPWS to say, instead of “bank angle”, something like “roll left” or “roll right”. He would like to add an arrow in the middle of the ADI pointing the way to roll upright. He certainly sees the point regarding a low speed warning prior to shaker, and said that would be terribly easy to do. He is all set to display little colored trails behind the TCAS target in front of you; green for safely above the wake, yellow for getting close, red for too close to the wake, and it’s all corrected for the current wind. I really did enjoy his attitude; at the conclusion of his pitch, he simply said, “Any more questions?...Great, we know how to do this stuff, so let’s do it!”

This was contrasted with extensive discussions about systemic study and change embracing loss of control but including such things as adaptive control, envelope protection, damage assessment, etc., along with some of the busiest powerpoint slides I’ve ever seen (and I’ve seen a few in my day). I remarked to one of my NASA friends that the difference between Bateman and some of the PhD crowd was almost funny. Don would be down in your hellhole right now tweaking up the EGPWS, while everyone else is still looking for funding.

That said, there was a lot of good discussion and work presented, and I think it will ultimately yield a lot of change. Academic education in fundamental aerodynamics was stressed by a number of folks, as well as a revisit to the Upset Training Aid.

BOAC
5th Aug 2010, 07:00
Thanks, Mansfield - reassuring to know and DB seems to be well on frequency. Any joint resolution on action?

A37575
8th Aug 2010, 12:36
For example, he pointed out that a simple code change will allow the EGPWS to say, instead of “bank angle”, something like “roll left” or “roll right”. He would like to add an arrow in the middle of the ADI pointing the way to roll upright.

I hate to say this, but isn't this a classic example of re-inventing the wheel? All this is basic instrument flying skill taught way back in the 1940's requiring interpretation of which way is up on the artificial horizon and use of the sky pointer. This can be practiced in a cheap desk-top trainer yet it is amazing how few airline pilots not military trained still do not know how to read their flight instruments much beyond a rate three turn - and no idea how to safely recover to straight and level if upside down in IMC..

error_401
8th Aug 2010, 13:46
Thanks Mansfield.

Do you happen to have any links to the most interesting parts of the happening?

Links to the speakers or their work would be very welcome as many publish on their own account and so it's free.

Mansfield
8th Aug 2010, 15:36
Unfortunately, AIAA seems to have removed the agenda from their website now that the conference is over. The best I can do right now is refer you to my post a week or so ago regarding the Loss of Control agenda:

http://www.pprune.org/5840551-post114.html

I'll send you more if I can find anything. You're correct to look for the same papers in a no-cost venue...any of the NASA stuff should be available through their tech server, if not now, then soon.

PBL
8th Aug 2010, 16:00
Just to save people trouble -

I have already looked for related papers from about the authors, for about half of the presentations on the WWW. None are yet there. Cox might well have been reporting on the work of the RAeS FOG group with which he has been involved. There is a report on his company's WWW site about their work on upset recovery, unfortunately undated.

It may be that AIAA requires the authors of their indexed papers to surrender copyright; this is usual amongst U.S. professional societies. In which case you generally won't find the originals elsewhere than on the AIAA site. NASA appears to be an exception. I am not a member but I can ask.

PBL

PEI_3721
8th Aug 2010, 17:03
A37575, “… re-inventing the wheel …”
Yes, but perhaps additional training would add impetus to a lethargic operation, or a system in the aircraft could strengthen a last line of defence.
Both aspects might assume that standards of training and/experience are changing, but this could be the result of weaker training / less opportunity etc; but as an alternative consider that the big picture has changed.

Have aircraft operations changed to the extent that the human cannot be expected to cope with all situations, be these aircraft system related (FBW/trim) or due to a complex operating environment (e.g. wake turb) - or both, its the combination which is the problem.
One solution is not to worry what causes the problem, but instead provide a line of defence.
Modern display systems should be able to aid decision making and encourage appropriate behaviour (assessing the situation and choosing the correct course of action), EGPWS/ACAS/PWS would be good examples.
An earlier (strategic) defence is to provide warning or protection against the situation; this probably entails more flight envelope limiting / auto recovery and increasing systems automation. This may be an attractive way forward to the operator, particularly if it saves training costs.

The alternative is to understand why the industry is facing these problems.
I fear that this is very difficult, primarily because it involves the human – a complex and occasionally irrational entity, and also a complex and often rapidly changing operating environment. Pilot employment cycles, management tenure, etc is often shorter that 3 years; regulatory change may take 3 to 5 years and any indication of the change’s effectiveness a further 3 years. And of course change can induce new, unexpected problems; thus the regulatory aspects develop slowly and usually retrospectively.

What the industry requires is some proactive thinking and activity associated with ‘reinventing the wheel’ or similar, and people like Don Bateman who have the engineering skills and tenacity to get things done.

Re links:
The following might provide an indication of some of presenters’ views.
2009 ER FTSW - Vienna, Austria (http://flighttestsafety.org/2009ER%20FTSWworkshop.html) see Carbaugh (17 Mb download)
http://halldale.com/files/halldale/WATS%202009/Proceedings/Cox.zip (40MB !)
http://www.halldalemedia.co.uk/WATS/PROC/Cox.pptx
http://www.scribd.com/doc/35550326/Aware-3 (http://www.scribd.com/doc/35550326/Aware-3) Download the ‘pps’ version for animation and sound.

Genghis the Engineer
8th Aug 2010, 18:03
There will be a similar event in London on 19 October, details here (http://www.raes.org.uk/conference/indexconf.html) (just scroll down until you get the right date.

G

Mansfield
9th Aug 2010, 11:30
Most authors are savvy enough to retain their own copyright; AIAA would love to own it, but does not require such in order to present a paper. In the case of government funded work, such as NASA, the copyright cannot be exclusive. AIAA will still sell the paper for fifteen or twenty bucks, but it should be available at no cost through other, government sponsored sources.

Some university originated work will be made available by the authors, particularly if it was generated through a government grant. It depends on who takes the time to create the necessary website, etc.

Corporately sponsored work, such as that from the folks employed by the manufacturers, will of course be available only through AIAA.

Genghis the Engineer
9th Aug 2010, 11:58
If you publish through an AIAA journal, the default licence assigns copyright to them, but there is an option to select that you retain copyright but just give them permission to reproduce. That's certainly the box I tick, but not everybody notices it, and they certainly don't go out of their way to point it out.

The other thing that a lot of academic authors do now is publish the final drafts (so all the words are in the right order, but the formatting isn't there) on their institution research archives. If you know which university they are from, look on the university website or try searching by paper title on Google Scholar, which should normally index all the open access archives.

That said, these archives can be a bit slow and sometimes take a few months to upload the papers.

G

clunckdriver
9th Aug 2010, 12:44
A37575, So true, When flying the heavies the make up of our pilots began to change from ex military to civilian trained pilots, many of who had not had the chance to fly upside down at the taxpayers expense, it became evident during sim sessions that we had to train for upset recovery to take care of this problem. We developed a system in which we would point the aircraft straight up or some other direction and without pre briefing watch the recovery efforts of the pilots, it was an eye opener! Some tried to push over with the resuling negative G and all the interesting thing that this would produce, engine flame outs, hyd pumps cavitating ect.Once we taught the "one G' roll towards the horizon recovery, things improved to the point that all our pilots were flying out of these situations without any problems, then came the Airbuss with its bank, pitch angle limits! Has such restricting the pilots contoll authority improved safety? In the case of well trained crews I think not {see threads re stall recovery put out by Airbus}In the case of the crews cranked out by some of the training systems today , it may have , unless of course the do get inverted or into a stall at high alt which might require some basic skills they lack , and the aircraft wont let then do it anyway.In the past even in light aircraft inhibiting the handling of an aircraft has not produced a safer uncrashable aircraft, the Aircoupe being an example of this. much simpler of course than the Bus.

LeadSled
9th Aug 2010, 15:43
Folks,
As Joe Sutter was fond of saying, you might overstress a Boeing airframe recovering from an upset ( and a few were) , but not Airbus FBW ---- until the Airbus hit the ground --- that would overstress it.
Tootle pip!!

Mansfield
12th Aug 2010, 18:02
To be fair to AIAA, most of the papers they publish are very, very dense, boring scientific treatises that are not at all easily interpreted by the uninitiated. Their safety relevance does not exactly jump out at you. This was the case for a handful of the loss of control papers, although perhaps not to the extent that is the case in other sessions, such as computational fluid dynamics codes used in three dimensional modeling of ice accretion on swept wings...you get the idea.

That said, I agree with the issue of locked PDF documents...once you actually get your hands on the them. I believe you will find some PDF recovery software produced by Ovis to be useful, although I have never actually had to recover a PDF document whose password I had...misplaced...:rolleyes:

PEI_3721
3rd Sep 2010, 01:57
Having had opportunity to read Don Bateman’s paper; the statistics relating to ‘cause’ are dominated by disorientation.
The primary defence against disorientation (avoidance and/or recovery) is ‘always trust the instruments’. See the automation thread here and onwards: - http://www.pprune.org/safety-crm-qa-emergency-response-planning/379780-computers-cockpit-safety-aviation-4.html#post5096487

Accepting the need for good instrument flying skills as a perquisite for upset avoidance or recovery (trust the instruments) then it is concerning to read evidence of weaknesses in these skills. http://flightsafety.org/asw/jul10/asw_jul10_p30-34.pdf
I wonder if this is at the root of LOC problems?

Do you really fly on instruments when monitoring automatics?

Also I have this thought:– can disorientation avoidance/recovery ever be taught without first being disorientated?

From my own experiences I don’t think that it can.

PEI_3721
4th Sep 2010, 01:48
IGh, the ‘assertive’ question is mine – is there a link between increasing number of LOC accidents (SD contributions 32%, 45% including Eastern ADI aspects) and instrument flying?
Although Don Bateman does not give a source for the data, to suggest that it could be mistaken requires strong substantiating evidence.

Within the generic term ‘Spatial Disorientation’, I would include a range of visual illusions; both aspects are identified in the presentation Understanding Spatial Disorientation (http://www.scribd.com/doc/36030283/Understanding-Spatial-Disorientation)

Whilst I would agree that there are many problems when investigating this type of accident, particularly fatal ones, the formal reports should not be discounted. Quite often investigations concentrate on the outward manifestations of the cause (the outcome); it may be all that remains to investigate.
As for crew recollection, remember that an illusion is the distortion of the senses, a misinterpretation of a true sensation; perhaps then the crew’s recollection is of the misinterpretation and not of reality.

An alternative view of the problem may be available from a wider range of pilots who evaluate themselves. They might consider how, when, and why there was potential for, or actual disorientation / illusion, and how it was combated. Similarly consider upsets or near upsets, how were these avoided.

Training helped? If so, what form of training, skill, and currency was most relevant?
These questions should be added to my previous ones.

bArt2
4th Sep 2010, 06:14
We developed a system in which we would point the aircraft straight up or some other direction and without pre briefing watch the recovery efforts of the pilots, it was an eye opener! Some tried to push over with the resuling negative G and all the interesting thing that this would produce, engine flame outs, hyd pumps cavitating ect.Once we taught the "one G' roll towards the horizon recovery, things improved to the point that all our pilots were flying out of these situations without any problems,

I've seen more than one civilian manual/handbook that has this one as the proper technique. I guess these are written by people who never did recoveries in real time (training).
If I ever need to use it in reality, I'll use the one I learned and thaught in the military.