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Indonesian aircraft missing off Jakarta

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Indonesian aircraft missing off Jakarta

Old 30th Oct 2018, 08:11
  #221 (permalink)  
 
Join Date: Jan 2009
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Witnesses say it fell out of the sky silently before hitting the sea with a crash.

Do aircraft crashing into the sea or land mass <10 mins after takeoff tend to do it silently?

gg
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Old 30th Oct 2018, 08:16
  #222 (permalink)  
 
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Originally Posted by wheels_down
That’s what I don’t get. The speed in which it sunk is off the charts. It’s extreme.

They have just fallen out of the sky. Literally.

Can you pull/push that severe that the tail or elevator rips off?
I know most of you Transport folks do your flying within 30 degrees of wings level, but when an aircraft rolls past 90 degrees, the nose drops really fast and the rate of descent can becomes extreme. This is most likely what happened in this case. Then the question becomes, what would cause such an upset?
Have any aircraft parts been found under the flight path away from the impact zone?


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Old 30th Oct 2018, 08:23
  #223 (permalink)  
 
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Originally Posted by garpal gumnut View Post
Witnesses say it fell out of the sky silently before hitting the sea with a crash.

Do aircraft crashing into the sea or land mass <10 mins after takeoff tend to do it silently?

gg
I think that you're placing a lot of emphasis on a very ambiguous statement, made by an untrained observer who was an unknown distance from the accident, which was translated from his native language to English by persons unknown. None of the other facts that we know, or think we know about this accident are remotely consistent with fuel exhaustion.
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Old 30th Oct 2018, 08:50
  #224 (permalink)  
 
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WHEN can we finally expect an AOA indicator in the flight deck?
That discussion finished when some smart engineers decided to place the engine and propeller at the front of the fuselage in the early 20th century, making a reliable AoA indication impossible.
This means in SEP initial flight training you do fly aircraft without AoA indication, so that becomes the standard of learning to fly. Very unfortunate, but practically impossible to change. A mix would probably be even more dangerous, than everybody relying on ASI...

So unless somebody develops a modern AoA Instrument which reliably works on all aircraft (e.g. a [email protected] doppler anemometer based AoA indication or something alike) and can be retrofitted to all training aircraft, there will be no quick solution.

Back to topic..

Does anybody believe in the altitude dip recorded for both flights?
For me this is indicating an issue with the static pressure measurement. I think this dip in altitude 23:21:40 to 23:22 for this flight and at 14:25 on the previous flight is an error in the data, and not the real flight path.
Especially as the curve returns to an expected one after a short time with no remaining offset.

Failure which occurs spuriously can not be created by a covered/blocked probe, such failures would intensify with altitude.
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Old 30th Oct 2018, 09:11
  #225 (permalink)  
 
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Originally Posted by Homebrew1 View Post
The 737 does a trim after liftoff. This is what I'm asking about. You don't have to be a dick about it. I was just asking a question re the new Gen 737's as the function of this trim may have or may not have been an issue. I haven't flown a 737 for 6 years.
Homebrew1 you are correct and the system you are describing is the STS (Speed Trim System) that is a speed stability augmentation system installed on 737MAX airplanes. It operates automatically and during operations of low gross weight, an aft CoG, high thrust and autopilot not engaged. It is common for STS to operate during takeoff, climb and go-arounds.

From the FCOM the conditions for STS to operate is:
  1. Autopilot disengaged
  2. 10 seconds after takeoff
  3. between 100kts and M0.68
  4. 5 seconds after a manual trim
  5. STS senses a trim requirement
The purpose of STS is to return the airplane to a trimmed speed by commanding the stabiliser in a direction opposite to the speed change.
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Old 30th Oct 2018, 09:12
  #226 (permalink)  
 
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Originally Posted by Volume View Post

So unless somebody develops a modern AoA Instrument which reliably works on all aircraft (e.g. a [email protected] doppler anemometer based AoA indication or something alike) and can be retrofitted to all training aircraft, there will be no quick solution. flight path.
Uhhh... AOA Homepage | MODX Revolution
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Old 30th Oct 2018, 09:21
  #227 (permalink)  
 
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Originally Posted by Volume View Post
Does anybody believe in the altitude dip recorded for both flights?
For me this is indicating an issue with the static pressure measurement. I think this dip in altitude 23:21:40 to 23:22 for this flight and at 14:25 on the previous flight is an error in the data, and not the real flight path.
Especially as the curve returns to an expected one after a short time with no remaining offset.
The speed increases significantly with the "altitude dip" which i would call a descent.
After that they climb at a higher rate because they are faster and are reducing speed, trading speed for altitude.

Someone even calculated total energy and graphed that to show that the data are consistent.

But that does not mean that there were no problems with static pressure measurement as the plane has multiple sensors and only the output of one of them is transmitted in the ADS-B data.
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Old 30th Oct 2018, 09:58
  #228 (permalink)  
 
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Originally Posted by garpal gumnut View Post
Witnesses say it fell out of the sky silently before hitting the sea with a crash.

Do aircraft crashing into the sea or land mass <10 mins after takeoff tend to do it silently?

gg
Witnesses are not quoted as saying that it ‘fell out of the sky silently’. The newspaper say that and then quotes the witness in relation to the noise and force of the crash and the ‘shock wave in the water’.
I see airliners all day and sometimes hear them, sometimes not, usually depending on wind direction. Because I dont hear them doesnt mean they are flying silently.
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Old 30th Oct 2018, 10:04
  #229 (permalink)  
 
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The FZ accident at Rostov showed it was possible for a crew to get the aircraft horribly out of trim manually at low altitude and lose control.
That’s another scenario that makes sense. The elevator is really only the trim for the horizontal stabiliser: if the stab has ended up in an extreme setting, for whatever reason, at low level a crash is almost inevitable...
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Old 30th Oct 2018, 10:17
  #230 (permalink)  
 
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Originally Posted by Andrewgr2 View Post
BBC are reporting that sonar is being used to locate the plane - Sonar Search I imagine they are trying to locate the pinging from the flight recorders.
No, Sonar search is not for locating pings, Sonar search is basically 3D imaging of seafloor with ultrasound. It gives you a large scale picture of the bottom. Wrecks and debris on the bottom becomes nicely visible.

For example:
http://www.flpublicarchaeology.org/b...edia_Sonar.jpg
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Old 30th Oct 2018, 10:48
  #231 (permalink)  
 
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Originally Posted by fox niner View Post
Air France A330
AirAsia A320
Lion Air 737

WHEN can we finally expect an AOA indicator in the flight deck? We need them. MAYDAY.
https://books.google.com.au/books/ab...AJ&redir_esc=y
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Old 30th Oct 2018, 12:36
  #232 (permalink)  
 
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Originally Posted by Retired DC9 driver View Post
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..

In this case, we have a log book entry. Why photograph it? The next crew cannot legally accept the aircraft until that log entry is signed off. This was done (we hope IAW the correct FIM procedure/AMM reference) and then it was photgraphed again. Why? Ok I can understand perhaps photographing the completed log book entry the night before and using that image to enter the details in whatever database Lion's maintenance use. I have done that myself when the log book copy is left in the book overnight and removed after the departing crew have entered their detais and signed off the log the following morning. But the photos that are circulating around the interweb are apparently of the removed log 'copy'. Why photograph it?

Strange.

Sky news are also reporting that the 'Technician' who signed off the aircraft has yet to be interviewed. Hmmm.
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Old 30th Oct 2018, 12:53
  #233 (permalink)  
 
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Originally Posted by billie
When the plane finally took off it seemed to be losing power in the first few minutes of flight and dropped suddenly a few times, passengers said.
That would be the power being reduced during the Unreliable Airspeed procedure. Entirely "normal' and expected in this scenario.
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Old 30th Oct 2018, 13:11
  #234 (permalink)  
 
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Originally Posted by Capn Bloggs View Post
That would be the power being reduced during the Unreliable Airspeed procedure. Entirely "normal' and expected in this scenario.
Did you read the other quotes in the article? Saying about people vomiting, like being on a rollercoaster and the delays prior to take-off. Is that all just a coincidence?
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Old 30th Oct 2018, 13:58
  #235 (permalink)  
 
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Now this does not exclude the possibility of high g-loads or abrupt elevator movements, the data is not fine grained enough to really say something about that.
Nor does it exclude the possibility that, as with most other accidents, the Flightradar data is unreliable.
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Old 30th Oct 2018, 14:34
  #236 (permalink)  
 
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Have any aircraft parts been found under the flight path away from the impact zone?
In the Boeing,asymmetric flaps are automatically limited to 6 deg so as to avoid asymmetric lift and the possibility of loss of roll
control.If the flaps were not retracted in the confusion of a UAS event,they could become over-stressed and depart the structure.If one assembly departs before the other side.this would explain the sudden loss of roll control and the ensuing dive.

The very last thing you'd do, confronted with a Unreliable Airspeed scenario, is try to race back to the field/"immediate return" and just "look out the window to land". These things provide NO seat-of-the-pants feedback like a bugsmasher does. With no other assistance, a UA landing is very difficult and requires careful planning.
Hmm...pitot-static anomalies are tricky.They arent trained much,they confuse quickly and are highly unforgiving.If the UAS is apparent after liftoff and it affects "both sides",then the last thing you want to do is prolong the flight.Ideally,you discover the anomaly prior to liftoff during the airspeed crosscheck at 80/100 and abort.However,some anomalies arent detectable until after liftoff.If the statics are the problem,then the ASI will read normally on the takeoff roll but in a climb it is measuring ram versus artificially high static pressure which leads to an ASI underread.You are flying faster than indicated.Opposite is true in a descent.If altimeters dont register a climb after liftoff and you get a windshear warning in calm air and/or a stick shaker you need to act quickly and RETURN.You dont fly around with unreliable basic instruments.You have 3 basic enemies in this situation:a)Confusion-your brain must disregard what your instruments are telling you b)Nuisance warnings-overspeed/shaker are highly distracting and you must block them out or disable them c)Time-the longer you expose yourself to the confusion and chaos the more stressed and fatigued you become.
In short if the UAS is detectable near terra firma,land asap.You have radio altimeter up to 2500',you have IVSI,you have IRS GS,you know your attitude/thrust settings for S&L and approach.Never attempt to engage automation as it is fed with the same false data.Stay in the circuit,NO CHECKLIST,fly the plane,ignore ALL warnings except EGPWS and land.
If its "single side" anomaly,you cross check the ASIs and hand over control to the pilot with the good data.You still return but now you have more time to play with,checklists may be done etc.
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Old 30th Oct 2018, 14:37
  #237 (permalink)  
 
Join Date: Aug 2017
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Originally Posted by RifRaf3 View Post
Re tech logs:
On a single seat aircraft, you had the privilege of viewing the tech log BEFORE you did the walk-around and this allowed for discussion with the ground crew so that you could pay extra attention to pertinent items during that inspection. This saved my bacon more than once.

Transit to B747 and it was not until after the walk-around and battling through pax queues and climbing two floors that you got to see the tech log. If the pitot/static system had been worked on you were unlikely to go back down and have a second look.

Perhaps with modern technology, the person signing off the tech log could simply transmit an image back to flight ops for the crew to peruse before doing the walk-around.
In our company its close to that, all maintenance items are shown on the PPS flight log under AMOS this shows the MEL were applicable DDR items are in the tech log ditto the last week or so history.
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Old 30th Oct 2018, 14:39
  #238 (permalink)  
 
Join Date: Jan 2015
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Originally Posted by dmba View Post
Did you read the other quotes in the article? Saying about people vomiting, like being on a rollercoaster
In the original Detik article, the female pax was quoted as saying that elderly people were vomiting in the ground due to excessive heat in the cabin. Not while in the air.
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Old 30th Oct 2018, 14:54
  #239 (permalink)  
 
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Originally Posted by LaissezPasser View Post

In the original Detik article, the female pax was quoted as saying that elderly people were vomiting in the ground due to excessive heat in the cabin. Not while in the air.
Alon Soetanto, a passenger on board the flight, told TVOne: 'About three to eight minutes after it took off, I felt like the plane was losing power and unable to rise.

'That happened several times during the flight. We felt like in a roller coaster. Some passengers began to panic and vomit.'
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Old 30th Oct 2018, 15:06
  #240 (permalink)  
 
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Originally Posted by A Squared View Post
that's no proof of anything. If they were receiving terminal radar services on departure, yes, it's highly likely that the controller would have observed the "dip", if he was paying attention. no, it doesn't necessarily follow that he would have reported it.
ATC may not have been providing radar services until the flight requested to return to the airport. And, hopefully, the airport's ATC radar is recorded.


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