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Indonesian aircraft missing off Jakarta

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Indonesian aircraft missing off Jakarta

Old 29th Oct 2018, 12:04
  #81 (permalink)  
 
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There is far more information in this electronic log-book entry compared to the picture of the technical log provided by Maisk. I wonder if the engineer repairing the IAS and ALT disagree fault was aware that the STS (stabilizer trim?) was running in the wrong direction? Normally a stabilizer is driven from the elevators' position, and is not linked to IAS and ALT. Is this a separate fault that was not noted, investigated and fixed? A stabilizer moving in the wrong direction compared to the elevators would be bad news regarding the controllability of an aircraft.
Originally Posted by etops777 View Post
*Ada info flight record* *penerbagan sebelumnya

A: PK LQP, B737 Max 8

D: 28.10.2018

O: Airspeed unreliable and alt disagree shown after take off. STS was also running to the wrong direction, suspected because of speed difference. Identified that CAPT instrument was unreliable and handover control to FO. Continue NNC of Airspeed Unreliable and ALT disagree. Decide to continue flying to CGK at FL280, landed safely rwy 25L

R: DPS CGK LNI 043

E: AFML

R: Capt William Martinus/133031, FO M Fulki Naufan/ 144291
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Old 29th Oct 2018, 12:11
  #82 (permalink)  
 
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Originally Posted by StormyKnight View Post


I agree, I wonder if this is the sort of speed you would reach if you were to put the throttles to the position they should go to as part of the checklist for an air speed indicator failure. We have had a lot of stalled aircraft in recent years, albeit at altitude, but my understanding is that there is a set throttle position & pitch that gives a reasonable guarantee that the plane will maintain altitude whilst diagnosis of the situation is performed assuming good working engines & flight surfaces.

correct the settings will ensure as a minimum a shallow climb or level flight.
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Old 29th Oct 2018, 12:17
  #83 (permalink)  
 
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AoA disagreement could result in ALT &/or IAS disagree
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Old 29th Oct 2018, 12:19
  #84 (permalink)  
 
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A squared, you can stall at 300 kts, an aerodynamic stall is related to the angle of attack of the relative airflow to the wing chord, not the actual straight line speed. A significant change in attitude at high speed will stall the wing but there would be an initial very high ROC. II donít think they stalled, LOC due unreliable airspeed seems the likely culprit. The Boeing 737 unreliable airspeed has you setting a power setting and attitude. This will result in a steady shallow climb and gives you time to identify the problem system. If you maintain altitude at about 5000í (instead of allowing the steady climb) with the required 75 or 80 % N1 ser you will accelerate to 300 kts easy and into the clacker. About 45-50% N1 for S&L at 5000ft. These figures should be known by all 737 drivers......just in case.
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Old 29th Oct 2018, 12:21
  #85 (permalink)  
 
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did the accident crew know about the technical issues of the previous flight?
Always read the last few pages of the tech log...
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Old 29th Oct 2018, 12:22
  #86 (permalink)  
 
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Aux tank, that’s the old airspeed unreliable memory item ch3cklist. It changed a few years ago, better look up the current one my friend.
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Old 29th Oct 2018, 12:25
  #87 (permalink)  
 
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Originally Posted by chillpill View Post
Every time there is an incident/accident, this place is bombarded with posts made by 'instant experts' based upon ADS-B data and tenuous links to previous events.

There is nothing professional about this. Nothing. It's also wholly disrespectful to those who have been tragically effected by these sad events.

I just wish we could leave this to the experts from the relevant countries safety authorities, accident investigation departments and other relevant stake-holders who are highly trained in such investigations and who are also motivated to get the answers as to 'why' as soon as practicable.

I know this is an open 'forum' but perhaps the moderators might consider some filtering to at least retain professionalism, facts and accuracy from posts made on PPRuNe, rather than drivel and conjecture, when we are faced with tragic events such as today.

RIP to all those lost.
Sorry, I disagree. Discussions like these often raise relevant points, even though they may end up unconnected to the incident/accident in question.

If some pilots reading this thread go and revise UAS drills for their type, then a lot of good has been done already. Given the aircraft history and the flight trace, itís a top contender but of course not verified until the report comes out - we know that.

Were you looking for the Professional Pilots Fact Network? I think you might have ended up in the wrong place. I donít think one exists but feel free to make it...
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Old 29th Oct 2018, 12:27
  #88 (permalink)  
 
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Well the new Airspeed unreliable NNC is somewhat amended

Originally Posted by Auxtank View Post
FOR 737 NG
Condition: AIRSPEED UNRELIABLE
The pitch attitude is not consistent with the phase of flight, altitude, thrust and weight, or noise or low frequency buffeting is experienced. Objective: To establish the normal pitch attitude and thrust setting for the phase of flight.
1 Adjust the airplane attitude and thrust. Maintain airplane control.
  1. PROBE HEAT switches . . . . . . . . . . . . . Check ON
  2. Cross check the MACH/AIRSPEED indicators.
  3. Cross check the IRS and FMC ground speed and winds to determine airspeed accuracy if indicated airspeed is questionable.
Note: Erroneous or unreliable airspeed indications may be caused by blocked or frozen pitot-static system(s), or a severely damaged or missing radome
2. Attitude and thrust information is located in the Performance Inflight section.
Additional Information

The flight path vector is based on inertial sources and may be used as a reference in maintaining proper path control

10.1
737 Flight Crew Operations Manual
FillieghHtiIgnhsltirguhmtents, Displays
Airspeed Unreliable
Condition: Airspeed or Mach indications are suspected to be unreliable. (Items which might indicate unreliable airspeed are listed in the Additional Information section.)
Objective: Toidentifyareliableairspeedindication,if possible, or to continue the flight using the Flight With Unreliable Airspeed table in the Performance Inflight chapter.
1 Autopilot(ifengaged).............Disengage 2 Autothrottle(ifengaged)...........Disengage 3 F/Dswitches(both) .................. OFF 4 Setthefollowinggearuppitchattitudeandthrust:
Flapsextended .......... 10įand80%N1 Flapsup ................4įand75%N1
-----------------------
5 PROBEHEATswitches.............CheckON
6 Thefollowingarereliable:
Attitude
N1
Ground speed Radio altitude
7 Refer to the Flight With Unreliable Airspeed table in the Performance Inflight chapter and set the pitch attitude and thrust setting for the current airplane configuration and phase of flight.
▼ Continued on next page ▼
Note: Stick shaker, overspeed warning and AIRSPEED LOW (as installed) alerts may sound erroneously or simultaneously.
Note: The Flight Path Vector and Pitch Limit Indicator may be unreliable.
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Old 29th Oct 2018, 12:27
  #89 (permalink)  
 
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Originally Posted by No Idea Either View Post
Aux tank, thatís the old airspeed unreliable memory item ch3cklist. It changed a few years ago, better look up the current one my friend.
Good spot - my bad. I've removed as not relevant. Thanks.
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Old 29th Oct 2018, 12:29
  #90 (permalink)  
 
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Sorry to ask but am I correct that this flight operated during daytime?
In good PPRuNe tradition I'm surprised not having seen the relevant METAR...
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Old 29th Oct 2018, 12:48
  #91 (permalink)  
 
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Originally Posted by ManaAdaSystem View Post


Not all pilots go through the previous write ups when they check the log.
If the defect was on the last flight, even the night before, surely the crew should be aware of all maintenance log entries before accepting the aircraft. Is it not SOP to review the log back to the previous flight? My own experience tells me this is so.

Also, is anyone else a little disturbed that a photo of the log book is available to read on the internet. Unless the log book has been discovered, dry and undamaged from the wreckage site that has to have been taken before the flight. Why? Who has released it? If that was my name on the log book I think I would be barricading the doors now. Relatives with pitchforks anyone?
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Old 29th Oct 2018, 12:50
  #92 (permalink)  
 
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Originally Posted by No Idea Either View Post
A squared, you can stall at 300 kts, an aerodynamic stall is related to the angle of attack of the relative airflow to the wing chord, not the actual straight line speed.

Sigh, yes, for the third time, I understand just fine what constitutes an aerodynamic stall. Yes, it is indeed theoretically possible to stall an airplane at high airspeeds. My comment was very clearly in response to another poster, who had speculated that the accident at hand may have been resulted from letting the airspeed decay and entering a stall, because of unreliable airspeed indications. My response was that given the GPS reported groundspeed of 300 knots, it was unlikely that this accident was a result of the pilots allowing the airspeed to get too low, with a resulting stall. Now, I am unsure why you chose to ignore the fairly obvious context of my remark and pretend that I meant something else, but it seems to be so that you can gratify your own ego by "instructing" me on basic private pilot information.
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Old 29th Oct 2018, 12:53
  #93 (permalink)  
 
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Originally Posted by Icarus2001 View Post
So at least two people above have no grasp of critical angle and what a stall actually is.
You have to purposely ignore the context of my statements to arrive at your erroneous conclusion that I don't understand what an aerodynamic stall is. Serious question: what is your purpose in playing this game?
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Old 29th Oct 2018, 12:56
  #94 (permalink)  
 
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Yes, it is indeed theoretically possible to stall an airplane at high airspeeds.
NO! Not theoretically. Actually. Or as the kids say now....literally.

Context noted but there were too many similar posts from others to let it be.

1. Reading too much into FR24 data is foolhardy.

2. An aircraft wing can stall at any airspeed.
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Old 29th Oct 2018, 12:57
  #95 (permalink)  
 
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Yeah- stall speed increases as the square root of load factor, so to stall at 300kt they would have needed to be pulling in excess of 9g- so, despite the fact the airframe would fail before that, no airline pilot is going to keep pulling with that kind of "G".
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Old 29th Oct 2018, 13:00
  #96 (permalink)  
 
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so to stall at 300kt they would have
Again, how do you know they were "doing" 300 knots. Airspeed versus groundspeed...

no airline pilot is going to keep pulling with that kind of "G".
Who said anyone was pulling? There are plenty of examples...

Can I respectfully ask then, what about "no airline pilot would put a three month old 737 in the water..."
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Old 29th Oct 2018, 13:01
  #97 (permalink)  
 
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Originally Posted by No Idea Either View Post
A squared, you can stall at 300 kts, an aerodynamic stall is related to the angle of attack of the relative airflow to the wing chord, not the actual straight line speed. A significant change in attitude at high speed will stall the wing but there would be an initial very high ROC. II donít think they stalled, LOC due unreliable airspeed seems the likely culprit. The Boeing 737 unreliable airspeed has you setting a power setting and attitude. This will result in a steady shallow climb and gives you time to identify the problem system. If you maintain altitude at about 5000í (instead of allowing the steady climb) with the required 75 or 80 % N1 ser you will accelerate to 300 kts easy and into the clacker. About 45-50% N1 for S&L at 5000ft. These figures should be known by all 737 drivers......just in case.
You can't stall a 737 at 300kts- it would break up first.
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Old 29th Oct 2018, 13:06
  #98 (permalink)  
 
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Again, how do you know they were "doing" 300 knots. Airspeed versus groundspeed...

Sure- but lets say there IAS was only 250- It would still take a lot of load.



Who said anyone was pulling? There are plenty of examples...


How else do you increase AofA?



Can I respectfully ask then, what about "no airline pilot would put a three month old 737 in the water...


Not deliberately- and it would take a large, deliberate control input to fully stall at those this speed.
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Old 29th Oct 2018, 13:06
  #99 (permalink)  
 
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Originally Posted by Icarus2001 View Post

2. An aircraft wing can stall at any airspeed.
A *theoretical* aircraft wing can stall at any airspeed. Above a certain airspeed, any *real* aircraft wing will experience structural failure prior to reaching critical angle of attack. I suspect, but don't know for certain, that a real 737 wing, which was traveling though the air at 5000 ft MSL, with no extraordinary tailwind, at an IAS which resulted in a groundspeed in excess of 300 knots, would experience structural failure before exceeding critical angle of attack. For certain, it would take extraordinary control inputs to force that wing to stall.

Last edited by A Squared; 29th Oct 2018 at 13:18.
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Old 29th Oct 2018, 13:12
  #100 (permalink)  
 
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..First, my deepest sympathies for the families of the passengers and the crew..

..Second, I believe some people may have gotten themselves in trouble, by posting
confidential information on this board..

Fly safe,
B-757
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