Hi A33Zab,
Apologize for posting slightly off-topic, but since you're here (and the subject has been touchhed in posts above), Is the Flare Law in the A330 similar to the A320? The FCOM wording seems to differ a bit between the two. I wonder if it's just a wording issue, or the A330 Flare Law is implemented differently, due to size of the a/c or other reasons... |
Airbus has Laws, Boeing has Modes.... :8
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From Airbus FCTM and from instructor support :
FLIGHT MODE ANNUNCIATOR The FMA is located at the top of the PFD screens. It is divided into 5 columns which indicate the operational modes of the AP, A/THR and FD. The columns are numbered from the left and indicate the following: The relation between the pilot input on the stick and the aircraft response is called the CONTROL LAW which determines the HANDLING CHARACTERISTICS of the A/C. |
FLARE LAW
@C_Star:
BPalmers explanation is extensive and correct if all works as advertised. In ALTERNATE - if due to multiple ADIRUs faults - do not rely on Hi AoA protection/Vc protection (ALT1) to kick in. @Winnerhofer: C_Star is correct: it is FLARE LAW not FLARE MODE. |
Winnerhofer
Basically Law is manner of flight controls response to side stick input. It uses the word mode as ground mode, flight mode and flare mode to define different laws in operation during that phase. Also it uses word mode to define phase of FMGC like Take off, Descent cruise etc. For instance in one document it says Thrust levers are also mode selectors meaning they can change the phase. It is used loosely. |
After five+ years of discussion about AF447 flight laws we start to search the definition of the words "law" and "mode" ...:{
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Quote: Originally Posted by Winnerhofer http://www.pprune.org/images/buttons/viewpost.gif Once the plane is in ALT, it remains in ALT until overseen by maintenance. Not exactly - Alternate Law is only "latched" (as in cannot revert to Normal) if the divergent conditions last for more than 10 seconds. A transient condition of less than 10 seconds will allow for a return to Normal Law in flight. In this case the pitot tubes were blocked for too long and Alt2B was latched. I have been lurking on the forums a while, but left the discussion to the experts. So with the big disclaimer that this is all coming from a non-pilot, there is one aspect that has been standing out for me: It is astounding how much into a 'tunnel visoned' Bonin must have been to miss that he was having the plane in climb for a total minute. It was night outside and it seems he left all the ECAM trouble shooting to his partner, so his eyes must have been on the PFD. Yet he seemed to ignore the altitude display, with the numbers constantly changing, aswell as the the climb/sink rate rate gauge. After around 25 seconds in, at FL 368 Robert tells him to mind his height, and Bonin explicitly acknowledges it ("Ok ok je redescends"). Some nose-down inputs on the stick follow, but, for a lack of better phrase, the stress must have pushed "height awareness" out of his mind again, as he continued climbing up to finally FL 378. It seems during those 60 seconds pre-stall a simple realisation like "My supposed FL is 350. I am 2000 feet above my FL, I must descend!" never materialised. In this thread and in the BEA report the term "startle effect" is brought up several times and it feels to be spot on. It's very hard to read the transcript and not think "If only Robert had been more insisting after he noticed the wrong attitude". |
Originally Posted by A33Zab
it is FLARE LAW not FLARE MODE
Actually Airbus is not too sure how to name it ... |
BEA Video
The official BEA video representation of the recorded flight data is meant for professionals.
So, how does it look for a professional? First of all, of course, a professional had already read all the available reports, interim and final. From the data, presented in those reports, a professional had already understood fully what had transpired on the flight deck of AF447. Still, reading data from graphs, spread out over several pages, makes it somewhat awkward to integrate, for instance, the stick movements with the aircraft attitude variations. The video does this information integration very nicely. Earlier in the whole discussion about AF447, somebody made a remark about the steering commands of the PF as if he was stirring mayonnaise in a mixing bowl. The video nicely illustrates that concept. The wild left / right gyrations of the sidestick do not seem to be justified by aircraft roll behavior. The total lack of situational awareness is illustrated by the useless slam forward / slam backward movements with the thrust levers and by the utter disregard for the pitch attitude. One can understand the tendency to initially start a correction in the upward direction, because the altimeter did dip down a couple hundred feet at the start of the event. However, there seems to be no target at all to strive towards resettling at FL350. It is all just blind panic to yank on the stick. An airliner at optimum cruise level has a pitch attitude of about 2.5 degrees nose up. The usual climb rate when optimum cruise level is reached, is 1.000 to 1.500 ft/minute. When a step climb is made, the engine thrust is sufficient only to sustain an increase in pitch attitude of about 1 degree! In normal words, an airliner at cruise level is as fit as an old geezer. There is no way that an airliner at cruise level can sustain 10 or 15 degrees pitch up attitude without massive loss of airspeed. Still, the video shows that just before the apex of the pull-up, there is a pull movement of the sidestick that shortly yanks the nose up to a whopping 18 degrees. The only reasonable explanation for the steering behavior is a panic mode, right from the start – but, the text from the CVR transcript had already shown that, the hapless comments, …. . Secondly, the video opens up again the hamster wheel of arguments about, if this had been different in Airbus, or that had been different in Air France - Baloney! Judging from accidents worldwide and on all types of aircraft, a certain percentage of pilots has no clue about real flying, no matter how many hours they have cruised airliners through the sky. Would stick shakers, interconnected yokes or simple old fashioned flight control systems have made any difference? NO. Look at West Carribean MD-82, 16 august 2005, over Venezuela, stick shaker ON, stall and yoke fully back all the way from FL330 into the ground. Besides the rattling stick shaker, there was also the call from the First officer, "Captain, this is full stall, full stall!" Look at Swiftair MD-83, 24 july 2014, yes, this year, over Mali, stick shaker ON, stall, wingdip over left and guess what were the yoke inputs all the way down from FL310 until just before impact? Full backstick and right roll! Especially in that latest case, there is no excuse possible along the lines of – how could we know? Well, by soaking up aviation knowledge perhaps, after all that has been discussed in the aviation world since 1 june 2009, the fatal date for AF447. |
@ CONF iture
Actually Airbus is not too sure how to name it ... AMM is more consequent about naming: FLARE LAW if as a function of EFCS FLARE MODE if as a function of AP/FD. |
A33Zab
As I said these terms are used loosely. Following is from A330 and A320 FCOM respectively where it says MODE. There is a little bit of difference between A330 and A320. FLARE MODE Ident.: DSC-27-20-10-20-00000273.0001001 / 23 JUL 12 Applicable to: ALL When the aircraft passes 100 ft RA, the THS is frozen and the normal flight mode changes to flare mode as the aircraft descends to land. Flare mode is essentially a direct stick-to-elevator relationship (with some damping provided by the load factor and the pitch rate feedbacks). At 50 ft, a slight pitch down elevator order is applied. Consequently, to flare the aircraft, a gentle nose-up action by the pilot is required. FLARE MODE Ident.: DSC-27-20-10-20-00001071.0001001 / 23 JUL 12 Applicable to: ALL When the aircraft passes 50 ft RA, the THS is frozen and the normal flight mode changes to flare mode as the aircraft descends to land. Flare mode is essentially a direct stick-to-elevator relationship (with some damping provided by the load factor and the pitch rate feedbacks). The system memorizes the aircraft's attitude at 50 ft, and it becomes the initial reference for pitch attitude control. As the aircraft descends through 30 ft, the system begins to reduce the pitch attitude to -2 °nose down over a period of 8 s. Consequently, to flare the aircraft, a gentle nose-up action by the pilot is required. |
@vilas:
You have convinced me,
They should change MODE here into LAW (like in FCTM/ISD/AMM) to prevent confusion with AP/FD Flare Mode. |
EMIT
Judging from accidents worldwide and on all types of aircraft, a certain percentage of pilots has no clue about real flying, no matter how many hours they have cruised airliners through the sky. Would stick shakers, interconnected yokes or simple old fashioned flight control systems have made any difference? NO. It just remains to explain why these 3 pilots have not practiced these skill during the decisive 4 minutes of the flight Rio Paris |
Emit
Would stick shakers, interconnected yokes or simple old fashioned flight control systems have made any difference? |
OZ8501
It would appear at this stage to be related to the thunderstorm activity along the flight path.
We all thought that we wouldn't see pilots pulling up into a stall again repeatedly but it happened in the swift air MD-83 accident this year. If this turns out to be a stall/weather related accident that will be the 5th in the last 10 years (West Carribean, Colgan, AF447 & Swift Air so far). Perhaps it is time to install stick/yoke pushers that automatically push the nose down upon repeated Stall Warnings? |
Originally Posted by Winnerhofer
(Post 8791661)
Why didn't the BEA do this filmed just as TSB did?
Originally Posted by Qantas_A380
(Post 8801886)
Perhaps it is time to install stick/yoke pushers that automatically push the nose down upon repeated Stall Warnings?
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Originally posted by Winnerhofer: Club 410, Club 430 and QZ's QRH |
Originally Posted by Turbine D
Originally Posted by Winnerhofer
Club 410, Club 430 and QZ's QRH
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Originally Posted by Winnerhofer: Here, for instance, is a Brazilian A330 crew dealing with a similar airspeed malfunction in 2003, according to a BEA report: What I would like to point out to you is the fact that there is a wealth of information about AF 447 contained in the previous 11 Threads. Going through the threads would save you internet surfing time and repeating AF 447 information that has been already covered and discussed. Below is a chart that was presented and discussed in AF 447, Thread #8… http://i1166.photobucket.com/albums/.../UASEvents.png |
Pitot Tube Icing
Looks like nearly all those events occurred in tropical regions. These days it may pay to be on extra alert when traversing tropical thunderstorms (especially if you cannot divert upwind) and be ready for either iced pitot tubes or iced AOA vanes.
Surprising how many events triggered stall warnings. I assume they were generated because of pilots pulling back on the stick upon autopilot disconnection. Baffling why Bonin was the only pilot who didn't drop the nose upon stall warning though. |
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