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Air Asia Indonesia Lost Contact from Surabaya to Singapore

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Air Asia Indonesia Lost Contact from Surabaya to Singapore

Old 1st Jan 2015, 15:44
  #861 (permalink)  
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Here's what I don't fully grasp (and won't until the FDR is recovered): the Captain had time on a F16. My understanding is that the F16 sidestick does not give feedback and moves very little. And obviously the F16 is a FBW aircraft as well. I would think this captain would have had one of the best shots at recovering the aircraft, if it was indeed upset by wx as is suspected. He should have also been very familiar with stall regimes at least on the F16 and I would suspect would have at least tried a few things in the sim.

Thoughts?
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Old 1st Jan 2015, 15:44
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Airbus Weather Radar
Does anyone agree that the current Airbus Weather Radars aren't as good as they used to be ? I've noted the following :

1) Weather picture suddenly changes from yellow to red as you approach closer to the cloud.

2) Auto-tilt is overly conservative (tilt down). Manual tilt needs to be used often.

3) Gaps between clouds disappear as you approach closer.
Re point 1; Each colour has a 'calibrated range' the range at which the colour is considered representative. Of course attenuation plays a large part too.

Point 3; I am afraid that's standard radar - the FCTM covers this quite well.

Hopefully this is an opportunity for the industry to self reflect and ask if current radar training is effective.
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Old 1st Jan 2015, 15:47
  #863 (permalink)  
 
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NigelOnDraft

Of course stall warning does come from the AoA sensors. What I'm saying is that if the AoA sensors are below the range where they give accurate readings then the stall warning should be sounding.

Did you have an answer about the implications of a faulty LGCIU triggering a change to Ground Mode?
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Old 1st Jan 2015, 16:00
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John Farley,
I was taught the same - and very good advice it was too!
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Old 1st Jan 2015, 16:15
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This is not AF447 thread

What is the point of debating AF crash here? We don't even know what has happened in this case, let alone looking for similarities!

Posting about AF here is just trolling and polluting. If you feel the need to attack plane maker A, do it elsewhere. Who is responding should just avoid the blatant, unmotivated provocation that leads to an hamster wheel that is even off topic.

Any other subject would be appropriate, for example noting that acoustic ping search has, for now, failed. No black box 'pings' detected in AirAsia search as officials identify body of flight attendant | South China Morning Post
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Old 1st Jan 2015, 16:22
  #866 (permalink)  
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It has been reported that the failure to detect any pings from the black boxes may be due to the rough weather being experienced today where 2 to 4 waves have been reported. A case of too much background noise in such conditions, to be able to detect the pings. Hopefully tomorrow will be a better day.
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Old 1st Jan 2015, 16:23
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Of course stall warning does come from the AoA sensors. What I'm saying is that if the AoA sensors are below the range where they give accurate readings then the stall warning should be sounding.
So now, when the pitot tubes ice up (as they did) and the CAS drops off (or any other ADR fault) you want the crew to be distracted by a constant blaring Stall warning - that no matter what you do with the aircraft (pull, push) - keeps sounding? This is a major design philosophy that when a sensor output fails or is deemed "invalid" we get a memory item QRH drill required?

As I said above, I think the 60KIAs / Stall warn on/off, is somewhat a red herring in this accident. If the circumstances and/or crew get an airliner (as this crew did) to below 60KIAS I think it is probably game over, and no amount of training or certification can cater for it? You're better off (as has happened to a degree) stopping the crew getting below 60KIAS / 40AoA in the first place

NoD
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Old 1st Jan 2015, 16:38
  #868 (permalink)  
 
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RE: F-16 stick and stall

Now that we have had AF447 hijack the thread, I may as well jump in where can contribute.

- The Viper stick might move 1/8 inch nowadays, but moved zero on first 40 or so ( I was in first squadron). So the family model was tuff because you could not see or feel what Joe Baggodonuts was doing up front, heh heh.

- The Viper has stall/AoA protection!! The criteria are vastly different than for the 'bus, but sameo sameo " you can't stall this plane". But wait!! Clever pilots/crews can do so, and procedure is the same for the Viper as for the 'bus.

Pull up and hold a high pitch atttude and then slow down before power can help your energy. You overshoot the AoA limiter. Unlike the 'bus, the Viper has a "deep stall" and not the "deeply stalled" condtion the AF447 crew saw. It has a pitch coefficient at 40 - 45 degrees AoA that prevents nose down and will sit there falling like a rock and happy as can be. Rudder anti-spin control law keeps nose reasonably under control. The elevators are fully deflected to get the nose down, but can't. So a manual switch takes away the limiters and you are in "direct" control of the elevators. Strangely, you still have positive pitch coefficient, so raise the nose and "rock" your way outta the stall.

Hope that helps.

Last edited by gums; 1st Jan 2015 at 18:21. Reason: technical error, spelling
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Old 1st Jan 2015, 16:39
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Question RE The Bus allows 2 people to work against each other

Cant help but wondering why both a feedback loop and some sort of vibrator on the sidearm controller when a discrepency re position/command is above a certain value say 5 percent. Thus even in a high noise environment, and with shtf, a tactile warning to " get your acts together " would be obvious and not dependant on visual or aural. ( above is a super simplified version- do not mean it is a minor tweak )
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Old 1st Jan 2015, 16:55
  #870 (permalink)  
 
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^

Well, what more is the airplane supposed to do? It is yelling "Dual input", the PFD has an arrow telling you you arent flying and lastly, we all learn from day 1, ONLY ONE PERSON can fly the airplane. "I have control" and that should be that.
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Old 1st Jan 2015, 16:56
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here some to learn regarding the weather radar,
However there is an interesting article somewhere that talk about how to master the Tilt Antenna function.
As you imagine it is important to have a "picture" of the weather in a vertical resolution and beside the fact that all the radars have a "kind" of gyro stabilization there is a simple formula to tilt your radar beam horizontally to the ground so you can judge your alternatives. the procedure if routinely preformed it takes 20 to 30 second.

http://www.nws.noaa.gov/os/aviation/...4dec-front.pdf
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Old 1st Jan 2015, 16:58
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Up Gust

@Bloggs --

But I don't think an updraught, in itself, will cause a pitchup;
?? A severe enough updraft will cause pitchup simply from differential vertical wind speeds between wings/nose and tail.

(But excellent points on "forgetting to remember trim" and "HMI is for the H and not the M".)

Also I am assuming at minimum an automation dropout (if not an outright counter-safety automation action) in AirAsia, until FDR data shows otherwise. (Too much similarity to other such instances.)

@fireflybob -- Remember that in this case they were in mid-climb already, presumably via automation, so I am not getting where you say "selected altitude" by itself would result in "lowered attitude"?
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Old 1st Jan 2015, 17:03
  #873 (permalink)  
 
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This is not AF447 thread
...but it is repeat of it nevertheless with folks brashly parading their collections of aeronautical ignorance way before any solid facts about the accident are known. Why does it never happen when Boeing or MD is written off, I half-a-wonder?

Originally Posted by John Farley
Of course I do not know what is taught these days.
Same. For me It's been the same last 18 years. Issue might be nailed by David Learmount quıte a few moons ago:

You may lead the pilot to the best practice but you can not always make him follow it.
...which, of course, may or may not be connected with QZ8501 accident. I suppose it is too much to expect the average PPRuNer to be acquainted with AC Doyle's warning about theorizing without fact.
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Old 1st Jan 2015, 17:06
  #874 (permalink)  
 
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@fireflybob -- Remember that in this case they were in mid-climb already, presumably via automation, so I am not getting where you say "selected altitude" by itself would result in "lowered attitude"?
jientho, yes it was a hypothetical point (sorry didn't make that clear) and agree it would be different in climb
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Old 1st Jan 2015, 17:07
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Lack of pings

Possible the tail separated during the upset and is in some location a good distance from current search?
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Old 1st Jan 2015, 17:11
  #876 (permalink)  
 
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It has been reported that the failure to detect any pings from the black boxes may be due to the rough weather being experienced today where 2 to 4 waves have been reported. A case of too much background noise in such conditions, to be able to detect the pings. Hopefully tomorrow will be a better day.
I'm wondering what kind of range they would be expecting considering the shallow depth and amount of surface traffic (noise).
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Old 1st Jan 2015, 17:20
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Originally Posted by The Ancient Geek
Regarding the inadequacies of weather radar in detecting many hazardous conditions there has been a lot of promising recent research using LIDAR.
Meteorologists are very pleased with the ability to better detect convective conditions but this is cutting edge stuff so likely to be many years away from routine use in aviation.

Maybe this will replace our current weather radars in the future. OTOH having a scanning laser on the nose of every airliner may prove to be too hazardous.
There is a problem that LIDAR does not work in heavy rain as the laser signal is too attenuated while the radar signal will work in all but the heaviest rain but is not good at identifying clear air turbulence. The answer in research was that both should be set up together.

Real issue is that turbulence may be rain wrapped or be sitting just the other side of a curtain of rain waiting for you to fly into it. This is where the human interpretation of the storm structure is needed. Honest research meteorologists will admit that this is not a simple problem every storm is different. This is why the rather less than useful advice is to avoid flying close to Cb. In all areas of the tropics and sub-tropics this would stop flying a large proportion of the time. However, it does lend support to the idea of a 'business trajectory' being used rather than fixed routes based on canned plans.
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Old 1st Jan 2015, 17:26
  #878 (permalink)  
 
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Weather Radar

A great source of wisdom and knowledge is : Archie Trammell
google it ...
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Old 1st Jan 2015, 17:28
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Stall warnings on AF447

Roseland,
In reference to your post #857, you are incorrect when you claimed that the stall warnings on AF447 stopped shortly after the captain re-entered the cockpit.
The stall warning sounded a total of 75 times during the fall of AF447 to the ocean. By my count, it sounded 29 times after the captain's return to the flight deck. Not once was it acknowledged by any of the crew.
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Old 1st Jan 2015, 17:32
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Originally Posted by JoeyBalls:8804780
@ Mixture

well, the safest thing would be to never take off...............................how do you think that will play out?

Also, people keep mentioning the CA was an F-16 pilot, so what? Flying an F-16 is absolutely nothing like flying an Airbus. The only commonality is they both are Yoke-less..............
Well the suggestion maybe that the F16 pilot has spent a significant proportion of his time maneuvering his aircraft to extremis of flight envelope in all conditions. A significant proportion of 20k hour commercial pilot time has been spent accumulating an hours actual flying time in every 9hr sector (e.g 30mins landing 30 mins take-off inc departure from ramp), with maybe 50% of the 'hours on type' spent in a 3 axis motion platform. So maybe just a little more than the yoke!
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