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Indonesian aircraft missing off Jakarta

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Indonesian aircraft missing off Jakarta

Old 29th Oct 2018, 23:43
  #181 (permalink)  
 
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Originally Posted by A Squared View Post
And an hour later, did it *still* show the airplane having landed, or had it replaced the data predicted in error with the correct data as received? I would expect the latter. But more to the point, I could see perhaps an writing an algorithm which predicts an airplane to have landed, when it notes that it is on a straight descending path pointed right at a runway, and if the airplane goes missed instead, it might take a few received data points and some data processing by the software to discover that the landing prediction was in error, and correct that. It seems a lot less likely that someone would write a predictive algorithm which would "predict" an airplane maintaining 5000 ft MSL and 300 knots, plus or minus random excursions either side of both parameters, for 6-ish minutes, when in fact the airplane did something completely different.
Yes Flightradar does predict the path of flights when the data stops in real time, but only for a minute or so, then the plane usually stops at that point, then a little while latter it disappears. The tracking line then reverts back to the actual data received & removes the estimated components.
When you view the flight later or download the raw flight data it is only the received data, there is no estimated flight data.
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Old 29th Oct 2018, 23:50
  #182 (permalink)  
 
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Originally Posted by das Uber Soldat View Post
Either something mechanical has failed, or after a contributing factor, such as unreliable speed that has been mishandled, structural damage has occurred that has culminated in the final catastrophic dive.
I find it difficult tp believe that in CAVOK conditions, a modern airliner crashes just because the instrumentation is screwy. They are fitted with perfectly good windows, if the engines are making power (and from the rate of climb it managed, they appeared to be) then power and attitude is all you need, even a low hour PPL can manage to fly around using the throttle and the view out of the window as their only reference. It's not exactly hard is it?

Something surely must have failed or fallen off ... nothing else makes much sense.
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Old 29th Oct 2018, 23:51
  #183 (permalink)  
 
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Originally Posted by flyhigh85 View Post


An aircraft can stall at any speed! It is the angle of attack which determines when stall (pitch angel) if they had flew at 350kt they would stall anyway if the nose was 40 degress nose up. A passenger airplane is is not designed nor have the trust required to do that, a rocket is a different thing.

i can’t remember exactly how it is but if your static or pitot ports are blocked (either one) your airspeed will increase with altitude. So if they put on the autopilot after take off the plane will pitch up and up to contain the airspeed increase and rather quickly put the aircraft in an unusal attitude, nose high low airspeed (actual airspeed). Autopilot will disconnect and stall warning alarms etc. If the pilots don’t react quicly and correct the airplane will stall. There might be a startle factor for the crew as well, which delay their reaction time. This only speculations from my side anyway. Tragic to see another fatal accident in Indonesia.
All very AF447 for sure, but very little basis for such wild speculation!
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Old 29th Oct 2018, 23:51
  #184 (permalink)  
 
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Originally Posted by ZAZ View Post

Get real man, parents and relatives come to these pages.
You have no information except some radar traces.
stick to flying mate let atsb do their stuff.
MH speculation all over again!
opinions are like backsides!
It's a rumour network - not an official ATSB page.
If you don't like it - go away.
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Old 30th Oct 2018, 00:23
  #185 (permalink)  
 
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Originally Posted by LaissezPasser View Post
Jon Ostrower has an interesting analysis over at The Air Current which notes that there are at least three different versions of that Aircraft Flight & Maintenance Log circulating in social media:

The chilling concern of this is not only that documents are changing in different iterations on social media but that a signed maintenance document might’ve been modified in some fashion to include a corrective action after the fact.
Ostrower's article is here:


https://theaircurrent.com/aviation-safety/the-perilous-unreliability-of-lion-air-logs-floating-through-social-media/

While he correctly points out that sometimes purported relevant documents posted on social media are fakes I would also observe that the pictures of different versions of the pink maintenance page are not necessarily inconsistent with the workflow of a maintenance signoff.

A lot of folks take pictures of the signed paperwork these days for CYA purposes, these pictures could be a shot of the inbound squawks and another of the page with the work signed off.
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Old 30th Oct 2018, 00:40
  #186 (permalink)  
 
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I've read this now I'm off to watch the Breaking News edition of "Air Crash Investigators".....but wait I could re-read PPRuNe
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Old 30th Oct 2018, 00:47
  #187 (permalink)  
 
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Not a Boeing guy, but this thread caused me to wonder the same thing, so I went googling. It appears that the 737 does have a trimmable stabilizer actuated by a jackscrew.
While we're raking over old coals (and I know we're talking of the MAX, not NG or Classic) can any of the technical posters here interpret the known data to categorically rule out the old 737 nightmare: Rudder Hard-over?

Please not. Let the Boeing redesign and service changes be the solution we all thought it was.
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Old 30th Oct 2018, 01:03
  #188 (permalink)  
 
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Originally Posted by chumley View Post
Maybe the beacon is operating but submerged. Bit early to make that comment.
Well the authorities are quoted that they went looking for a beacon and couldn't find one. The idea is that one floats to the surface to identify position and then the underwater beacon pinpoints the wreck. Non hardened satellite beacons are a few hundred dollars. Hardening one to withstand extreme G and also floats is not trivial. My proposal is to have several around an aircraft to try to beat the chaos theory.
The underwater locator beacon has limited range so there is a need to start the search close to the wreck, we learnt that from flight MH370.

Mjb
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Old 30th Oct 2018, 01:11
  #189 (permalink)  
 
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Originally Posted by das Uber Soldat View Post
Welcome to 2018, where facts are racist now.
however on the data presented there is no loss of energy and the aircraft maintains tremendous speed until impact.
Well there was a loss of energy, but there was a gain in speed (and you're right about your inference, under the assumption of ~1G, of the very low likelihood of stall). In a discussion like this it's particularly important not to say "energy" as a stand-in for "kinetic energy." Normally that's a nitpicky pet peeve of mine, but here it actually matters as it introduces an ambiguity in a central area of the discussion.
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Old 30th Oct 2018, 02:08
  #190 (permalink)  
 
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Originally Posted by Airbubba View Post

Ostrower's article is here:

https://theaircurrent.com/aviation-safety/the-perilous-unreliability-of-lion-air-logs-floating-through-social-media/

While he correctly points out that sometimes purported relevant documents posted on social media are fakes I would also observe that the pictures of different versions of the pink maintenance page are not necessarily inconsistent with the workflow of a maintenance signoff.

A lot of folks take pictures of the signed paperwork these days for CYA purposes, these pictures could be a shot of the inbound squawks and another of the page with the work signed off.
I know of only one large European airline that uses this technique, and even then it is only to send data back to base to show the real time airworthiness state of the aircraft. IE. one photo to show the a/c has a defect and that the problem is 'in work' then a second to show the sign off and CRS. Also, the log entries that we saw earlier in the thread that have now been removed looked exceptionally neat and tidy. My first language is English as is most of my colleagues, but our log entries are rarely much better than your average GP. Seems a bit suspect to me.

What is CYA?
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Old 30th Oct 2018, 02:12
  #191 (permalink)  
 
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What is CYA?
I believe it's Cover Your Ass. I do this myself from time to time.
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Old 30th Oct 2018, 02:15
  #192 (permalink)  
 
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ATC

Did they at any time declare an emergency?
The authorities said they aircraft requested ATC to return and no further contact afterwards. With the Fr24 data available we can see the situation was serious very early in the flight, surely a full emergency would have been declared.
Yes, I know, fly first talk later but there must have been concern on the ground and some attempt at communication.
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Old 30th Oct 2018, 02:15
  #193 (permalink)  
 
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Originally Posted by TURIN View Post
What is CYA?
Cover Your A**.

See: https://en.wikipedia.org/wiki/Cover_your_ass
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Old 30th Oct 2018, 02:24
  #194 (permalink)  
 
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Originally Posted by Vessbot View Post
Well there was a loss of energy, but there was a gain in speed (and you're right about your inference, under the assumption of ~1G, of the very low likelihood of stall). In a discussion like this it's particularly important not to say "energy" as a stand-in for "kinetic energy." Normally that's a nitpicky pet peeve of mine, but here it actually matters as it introduces an ambiguity in a central area of the discussion.
I say energy as a stand in for 'energy'. GPE + KE = Energy. Looking at the graph, total energy remains relatively constant.

Does it not?
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Old 30th Oct 2018, 02:31
  #195 (permalink)  
 
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What is CYA?

Cover- Your- A*s

If Maintenance say "you're good to go", well take that with a grain of salt. Put a snag in the logbook, call maintenance so they " know" you have a snag in the log, then they have to answer it, consult the MEL, and sign off the snag with a signature. Then a copy is in the system, plus there is a answered snag in the aircraft logbook.. Or wait for a part/repair before the aircraft is good to go.

Always keep a copy , if you can of any irregular ops , ie datalink messages from crew sked, "you are legal to fly an extra leg" or whatever..
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Old 30th Oct 2018, 02:36
  #196 (permalink)  
 
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Originally Posted by Longtimer View Post
New aircraft only 400 or so hours, you have to wonder what the hell the problem could have been. New aircraft don't fail unless ……………………………..
"Murphy's Law" applies to all a/c regardless of hrs or age.
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Old 30th Oct 2018, 02:56
  #197 (permalink)  
 
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[QUOTE=Volume;10295496]If airspeed is unreliable, it does not matter that it indicates the aircraft is going fast.
Unreliable might mean too hig, unreliable might mean too low, for sure unreliable means neither the pilot nor any speculations should rely on it...

This is the part that doesn't seem to make sense. VMC/Day. Plenty of fuel, lots of time to work the problem?

Are we missing something here?
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Old 30th Oct 2018, 03:00
  #198 (permalink)  
 
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[QUOTE=Volume;10295496]Anyway, the aircraft took of around 90 Minutes after sunrise in good weather. Quite different from Birgenair or AF, there was clear visual reference all the time. Good pilots could handle aircraft under such conditions even after full loss of instruments...

This is the part that doesn't make sense to me.

Are we missing something here?
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Old 30th Oct 2018, 03:01
  #199 (permalink)  
 
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Do FW training schools not teach manual control manipulation? Day, CAVOK, setting a power figure you know is cruise or whatever profile you require. Fly the attitude!
Compass and GPS Ground speeds and heights are not pressure tube connected. BASICS are missing from todays Hi-Tech 'Auto-Pilot' Eerr what's it doing now lah, crews. Air France 447 plus a few others recently.
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Old 30th Oct 2018, 03:14
  #200 (permalink)  
 
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Originally Posted by das Uber Soldat View Post
I say energy as a stand in for 'energy'. GPE + KE = Energy. Looking at the graph, total energy remains relatively constant.

Does it not?
No, it drops off precipitously at the end, along with altitude as the speed shoots up. But more to the point, it's speed and not TE that matters for ~1G stall. You can haul any low-performance plane 45 degrees up and coast it into a stall, and the TE will stay about the same. I.e., you won't be able to tell what's about to happen from a TE graph.
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