Metric callouts?

Lately when I try a post, it fails to post and I am automatically (?) logged out. Not that I have that much to offer, but it is strange.

I prefer to think of HF as judgment and abstract process, not floormat under pedal sender. Also CRM.

I take your point re: LAW degrade ROLL, while remaining consistent in PITCH. The serious problem as I see it is retaining both in the same stick.

Try teaching yourself to reconsider the control as sensitive in one plane, and in the other, not so much. Unlike others here, I don't think PF had ham hands, or a "death grip" on the stick; I think he was focused on keeping 447 off her back. In doing so, he slid through fore/aft movements, and..........

BEA stated that after the a/c was commanded up, it was not immediately responsive. That does not mean she didn't climb. Also, AoA was well ahead of PITCH, consistent with a strong updraft. We'll have to see why the a/c commanded 5000fpm down for thirty seconds prior.

Again with the making stuff up. The nose pitched to a max of 1 degree down briefly for 3-5 seconds at 02:10:00 (still in autoflight). Disconnect happened at 02:10:05, at which point the pitch attitude was approximately zero. The climb starts at 02:10:15, because the PF has manually set the pitch attitude to about ten degrees.

The aircraft does not exceed 20 degrees of roll throughout the disconnect/zoom climb part of the sequence and only starts to approach 40 degrees of roll once the stall is well established. The protection limit of Airbus FBW is 67 degrees of roll. 40 degrees of bank is definitely out of the ordinary, but the notion that the PF was fighting to stop the aircraft from going on "her back" is nonsense.

Cruise: +3. Add 1 degree, FOUR degrees nose low. And CLIMBING.

The airframe is not Protected in ROLL in AL2, so your "67 Degrees" is meaningless.

in both of this videos is the speed of stick move maybe faster
(between 1:20 and 1:30.....)



ok both are landings with slower speed, and low altitude, and the first one is not an A330 but to stir one`s coffee is obviously not unusual....???

@ lyman exist the (very smal) possibility of a undiscovered worn or brocken rod-spring into the sidestick ???

No - this is what we call "moving the goalposts" in the UK.

No - even if you go by the vertical speed trace (which starts climbing before the altimeter trace), climb is not established until 02:10:11, at which point the pitch attitude is approximately seven degrees nose up and continuing in that direction.

You misunderstand me - I was not saying the aircraft was protected, I was saying that even with the aircraft at it's max bank angle in the stall, it was 27 degrees shallower than the absolute maximum the computers will allow when the protections *are* working, hence any idea that it was about to go inverted is complete hogwash.

I know you want to believe in a heroic PF that was wrestling a bad aircraft, but it simply is not borne out by the evidence. What we have is a relatively young pilot who was badly let down by his employer and was never trained for the situation in which he found himself. Having not been trained, he made the wrong choice when he raised the nose beyond five degrees. He compounded that by making another wrong choice and trying to keep the nose up and applied TOGA. He made a further wrong choice when he tried to deploy the speedbrakes. Bad move after bad move after bad move - but he'd never been told the right move.

@grity - Very unlikely, or the BEA's simulated responses would not have tracked so closely. The videos you post show normal sidestick deflection during low-altitude operations, including takeoff, initial climb, approach and landing - but you shouldn't see those kind of deflections in cruise.

Impression from one who has no idea WTF he's talking about
 

@grity's videos:
Yi-yi-yi-yikes!!!
It certainly appears that the mayonnaise is well-blended.
(I do not want to fly in an elaborate video game!)
Thanks for these wonderful videos.

Something new occurred to me, although highly unlikely:
I wonder if the stick had a broken transducer. Perhaps that could explain all of these seemingly unexplainable inputs. Of, course, we hear no (as so far published) verbal feedback that would indicate such. Just another unsubstantiated thought to argue about. :rolleyes:

Grity,
The two videos are a bit of apples and oranges comparison with the AF447 initial PF control motions. Let me try to explain why:

First, the aircraft are landing, so the followng applies:




Third, There is a major difference in the control techniques displayed compared with the AF447 PF technique.

• In the videos, the majority of the control inputs are pulses from neutral (Until Flare mode is activated).
• On AF447, the control inputs were continuous.

Couple of things to note about the 330 vid at JFK:

1. At 33 secs point, after A/P disconnect, "Flight Directors, OFF".

Not dealing with SS moves, but I think fair game for a Tech Log comment:

2. RAS info on final: "Approaching 22 Left." Well and good.

RAS info on the runway after NW touchdown: "One thousand, two hundred remaining."... "Nine hundred remaining." Sure looked like a lot more than 900' remaining to me based on runway markings. They may need their RAS database checked. 22L is 8400' & the double high speed taxiway they passed on the right is only half way down. :confused:

(BTW Mach' stated the above post very well)

Mach', your post got shifted, but I think you're right about metric, it is a customer option. :)

The incompatibility with this on a US runway is that the callouts would not numerically coincide with the distance remaining markers.

And the RA callouts are in feet.....:confused:

(This random posting is like trying to talk to my wife.)

(And actually it's RAAS not RAS)

Board problems.

Re the comments about DTG and post ordering, as well as difficulty posting - I raised these with the hierarchy yesterday and the answer came back that we are experiencing the problems across all forums.

Both problems are ones we have had periodically in the past and it is a matter for the boffins to tweak a bit to fix things.

The delay on this occasion falls to the US holiday. Hopefully we will see the problems disappear shortly.

This random posting is like trying to talk to my wife

All of us married chaps have to let that one through to the keeper ...

There will always be an England
 

@john_tullamarine
"...boffins.."

Isn't that some sort of a fish? :)

Guess I have to admit to being a boring old phart dinosaur of an engineer.

Dozy, please tell me what was bad about deploying speedbrakes?

The mistake was not leaving them out long enough to realize that they had no effect on the aircraft. If PNF had not climbed all over him immediately for selecting the speedbrakes, they might have had a chance to realize that the aircraft had something other than "Some Crazy Speed."

PNF was so uneasy by then, the "emotional sparks" in the cockpit must have been a foot long. This interpersonal tension interfered with everyone in the cockpit's ability to reason.

I would expect the PF to notice the different 'feel' of a stick with broken spring. The AB simulation is based on the recorded SS position, why would it be affected by 'feel'?

Springs, force transducers, physical feedback, et al
 

Salute!

Looks like more efforts to blame the Bus versus the pilot, or a combo.

I have gone on record as feeling some Bus design features did not "help" the crew, but also feel most blame will still rest upon the shoulders of the crew and the mentality that the jet will "protect you".

Our physical feed back from motion/position of the stick is pretty decent if flying something as I did. Larger roll and pitch rates, and the inner ear sensors and the gee sensors in your butt helped. But the big heavies don't respond all that fast, so using visual cues ( like the instruments or outside the windshield) is the primary feedback, huh?

Spring failure is a red herring, IMHO.

About the only thing I would do is add force transducers to the grip as we had in the SLUF. That sucker had the same stick grip as the original Viper. So with "control augmentation" active, the first four pounds of stick pressure commanded control surface deflection with the angular position of the stick "frozen". Used to test this on test flights. Above the four pounds of pressure, you had to move the stick in an angular fashion, just like the "old" planes. If anything, the springs on the Bus stick may be too light. Maybe increase the pressure/force required to move that sucker a lot.

Just some thoughts from an old dino.

Quite a jump from computer-simulated molecules. Clever molecules that avoided the ice detectors?

Netstruggler, I am trying to explain to the non pilots on this forum just how difficult it would be to deal with varying control harmony.

When was the last time you flew an airbus at FL350 in roll direct? Does the roll response remain constant when roll rate degrades to roll direct?

A/P off. A/T off. F/D off. Thrust climb. What speed will it maintain?

Dozy, they didn't know that. Since the speedbrakes were rising from the wings into the wake of the stalled wing-there was minimal incremental drag. The effect was minimal with regard to incremental AOA.

If they had really been going at some crazy speed, they would have been thrown forward in their seats and had that impression confirmed.

As it was, they felt no more deceleration sensation than if the aircraft were on the ground, parked. That lack of sensation should have been a big clue, but the crew were so keyed up by then, they did not recognize the significance of the brief 3 second activation and its lack of deceleration.

It was not an error to deploy the speed brakes when PF did so.
The error was letting PNF cow him into retracting them prematurely.

Hi,

Zorin_75
These pilots have behaved like small children
Indeed .. in presence of a toy (to awaken the sens of curiosity) with levers and buttons of all colors a child will operate them out of curiosity
If its action on a lever will give a result (eg music) it will start its work on the same lever for a while
If there is no immediate result .. it will handle quicly one after the other without interruption the levers and buttons and will be frustrated
This is exactly what makes these pilots

mm43

re: post #510

please define the boundaries for this relatively short time.

I doubt that the reader knows what it is relative to Micoseconds, seconds or minutes etc.

Dear Dozy,

I agree with you about the speedbrakes, in that they should play no part in any stall recovery, other than to ensure that they are retracted.

However, I disagree about the stall being irrecoverable. In modern airliners, an irrecoverable stall (the oft misquoted 'Deep Stall') is purely a feature of 'T tailed' aircraft, hence the certification requirement for a Stick Pusher on such types.

A conventional, low tailplane type such as the A330 should never enter an irrecoverable stall. In the case of AF 447, the self-inflicted stall should have been recoverable by pushing the sidestick forward, then helping the desired pitch change with judicious use of nose-down trim. Depending on the altitude, recovery should be accomplished with no more than 3,000 feet of height loss. (IAS/TAS relationship + momentum.)

For the thinking Airbus pilot, on seeing the amber crosses on the Flight Director, which indicate reversion to Alternate Law, the first thought should be:
"Loss of protections - especially Stall Protection."

The next action (CRM) should be to pass that warning to the PNF, with the rider "Watch my back!" Simply, basic Airmanship.

expected yes shure, a broken spring is easy to feel but a worn spring?

did we know how long ago the right SS was not in use? hours? days? weeks?

is it absolut impossible that he feels his (halfback-)stick position as allright?

Honda, Toyota and BMW have all provided variable gear ratio steering systems.

Electrically Variable Gear Ratio Steering Systems

and they all make some very good cars.

They don't vary anything randomly of course, but then neither does the Airbus.

Both SS are checked on every taxi out for proper control surface deflection, as well as noting the index cross on the PFD displays for proper SS longitudinal & lateral limits and the neutral position, plus checks of the priority system & dual input advisory.

I understand what you're getting at, but at the same time the PNF seemed to be aware that they had an unstable aircraft - unfortunately we don't (and will never) know if at any point he suspected stall. I'm not an aeronautical engineer, so I don't know what effect throwing out the speedbrakes would have in a mushing stall. I doubt it would be positive.

OK hours, then the chance is less 1/100.000 that a worn spring plays a role,

(100. 000 are +/- the hours in 10 jears, and in my experience a spring can worn but normaly work longer than 10 jears....)

thats the range of murphys law......
was the SS rescued?

Worn springs?
 

Since I presently design products that sometimes use springs, I have some passing familiarity with spring failure modes that may apply to an aircraft feel system. They are:

• fracture and
• relaxation.

If you operate the spring into the yield range of stress, you can expect loss of strength over its operating life-This is a gradual degradation.

Otherwise, sufficient cycles can fracture a spring eventually depending on the applied loads. Once a coil type compression spring fractures, the broken ends slide past each other and the spring will shorten, decreasing the effective spring length. This would be the most hazardous failure mode in an aircraft feel system.

In an aircraft feel system such as used on the A330, the springs are enclosed in housings that limit ultimate compression and protect against FOD. The design would avoid stress levels that exceed the Soderberg criterea, thus providing reliable service over the lifetime of the aircraft.

All that you probably ever wanted to know about spring failures can be found here:Mechanical-Spring-Failure-Modes

They were stalled, that's what was bad about it! They were mushing at that point, and slowing down further might have rendered the aircraft completely unrecoverable.

Dozy, what MB is getting at is, rational thinking provided, the marginal effect of speedbrake deployment could have told them that they were very slow. It didn't look much like a methodic attempt at troubleshooting though...

Very clever!

Which leads me to ask if the ice detectors have always detected ice in other recorded UAS events?

Having had another look at the ATSB's report on two UAS events recorded by VH-EBA on 15 Mar and 28 Oct 2009, I failed to find any reference to ice detectors mentioned. Anyway, I extracted the Icing Environment graphic from the report and plotted the AF447/F-GZCP data on it.
http://oi40.tinypic.com/1tqys1.jpg
The argument for "super-cooled" water being the culprit, goes along the lines that as the probes are already heated, they provide the ideal impurity point for the "seeding" and instantaneous conversion of super-cooled water into ice. Likewise, the melting of this ice occurs in a relatively short time.

Ice detector
 

mm43;

The ice detector that I'm familiar with (Rosemount, IIRC) detects the formation of ice due to freezing of super-cooled liquid water on its unheated ice-collecting element (*). It does not detect ice crystals floating in the atmosphere. Ice crystals do not adhere to unheated surfaces, but may be 'caught' inside a pitot tube.

(*) Quote from AIAA paper 2006-206 "The Ice Particle Threat to Engines in Flight" by Jeanne G. Mason et al.: In 2002 one large transport aircraft engine powerloss event occurred on an aircraft equipped with dual Rosemount Ice Detectors (RIDs), one on each wing. When exposed to supercooled LWC, ice accretes on the exposed rod of the RID until it reaches a threshold mass, at which point deicing heat is applied to the rod and a ‘trip’ is registered.

lomapaseo;

Re: post #502 (in reply to my post #512!)
There's that word "relative" again!

In the case of VH-EBA the UAS was for about 8 seconds and the SAT was -48°C. AF447 had UAS for 30 seconds (longer on the ISIS) and the temp was -43°C. VH-EBA had Goodrich pitots and F-GZCP had Thales, so it's not possible to compare directly for any relationship between ice build-up and time, though that's likely.

Neither do we know whether ice crystal accretion over time is responsible, or a near instantaneous build-up due to "super-cooled" water seeding into crystals on contact with the pitots. In the case of both aircraft, pitot blockage/unblockage occurred rapidly.

The "relative" part of your comment can only be answered subjectively on the basis that a small ice accretion will last a short time (seconds) and a larger one will last relatively longer, but still in seconds.;)

As I recall, the issue with super-cooled droplets as opposed to ice is that while contact with impurities cause them to freeze near-instantaneously, the operative term is "near" - they can progress backwards along a moving surface some way in that fraction of a second, and that was part of what caused the problems with the ATR back in the '90s because the droplets ended up freezing as ice behind the de-icing boot. If the droplets don't freze until they are behind the ice detector then is is possible that the ice detectors can't detect their presence in a similar manner?

@Lyman - it's right there in the DFDR traces.

http://i1088.photobucket.com/albums/...r-pitch-vs.png

The aircraft climbed due to elevator movement and rising pitch attitude (see red line), *not* because of an updraft.

@2:10:08. "I have the controls"

The referenced paper offers a number of arguments for the prevailing opinion that the high altitude power-loss events, and perhaps also the pitot problems, are caused by convective clouds containing a very high density of tiny ice crystals. The point I was making in my post is that the well-known Rosemount Icing Detector does not detect ice particles, since it is designed to detect super-cooled liquid water droplets. BEA says that the presence of liquid water at -40° C is unlikely, and must necessarily have been limited to small quantities. If there was liquid water in sufficient quantity to cause icing problems, I think it is highly improbable that it would have been missed by the ice detector(s). If your scenario was valid, how could they ever detect ice?

I don't think that you are correctly describing the cause of the ATR accident at Roselawn. IIRC, the theory is that the airplane encountered unusually large super-cooled droplets at relatively low altitude. Due to the large droplet size, the area of ice accretion extended beyond the deicing boots. While the ice on the boots is periodically shed by inflating the boots, the ice aft of the boots remained and formed a ridge on the upper surface of the wing just aft of the boots. This is just from memory, feel free to correct me. I don't see any connection to the functioning of an ice detector.

mm43

Re post # 514
OK it's seconds then:ok:. Since we are talking about AF447 the time to clear the ice and reestablish valid pitot readings is iimportant.

My feeling is that this time would not be expected to be much different than all the other inflight incidents, in other words seconds

Dozy (cc Old Carthusian)

Re: Attitude and "climb".

Dozy, The Nose was actually Low by four degrees v/v flight path, so no goalposts were injured in the making of this post. The a/c was "climbing" nose low ........-4 degrees. The auto pilot will trip out with a NOSE Down of 9 degrees, so I offer this theory, try it on.

For thirty seconds prior to loss of Auto Pilot, the VS select shows 5000fpm down.

This value would trip the a/p due excessive Nose Down, so it is rejected by the FCM. Select/Reject for thirty seconds. NO ICE. The a/p eventually latches the excess (+9) value, and trips out at 2:10:05. NO ICE. As the a/p has tripped due to excess control (past limit), the LAW remains in NORMAL. For an additional ten seconds, the a/c is subject to turbulence that duffs the probes, simultaneously. NO ICE. With discrepant normed Speeds, the a/c degrades now into AL2 NO ICE. It is at this point The PNF announces, "We have lost the speeds, Alternate Law..." NO ICE.

For an updraft to lift this a/c (at the recorded rate) is remarkable. It also screws with the AoA vanes. As the Pitch decreases, the vanes read increasingly higher. PITCH at this point is not the a/c's problem, but AoA is. This is why the a/c initially did not "climb" with PF's aft pulled stick. The elevators were trying to catch up with the airstream, for the better part of ten seconds.

At the point that the elevators got back into the "loop" the climb was already breathtaking, and virtually unnoticed in the cockpit.

Were they in the cell? I believe they were......

EG: Can an aircraft climb rapidly with a Pitch displayed as 'Normal'?

Boy Howdy.

thanks fore the link ,

if worn is the wrong word, then sorry I meant relaxation.... is it one spring for pitch or one for push and one for pull into the sidestick??? If I remember well gums has shown a diagram of the energy vs move of the sidestick in thread 3(?) with a kink in the line, so mayby there works more than one spring in each direction

Read me a little closer, Doze. Whose elevator? Whose VS select?

A/P. Not PF. What are those oscillations in VS (SELECT)?