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pianos101
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Thu Nov 01, 2018 5:15 pm

fadecfault wrote:
A full pitot static test should have been accomplished and it would have shown any disagreement with the pitot and static systems.


Based on the tech log circulating, they did flush the LH pitot system and then completed the ops test, which was satis. They didn't *just* do the ops test. Looks like they followed the IFIM, which basically tells you to flush the pitot system.
 
dakota123
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Thu Nov 01, 2018 5:40 pm

More details from the preceding flight: https://www.reuters.com/article/us-indo ... SKCN1N64ZE
“And If I claim to be a wise man, well surely it means that I don’t know”
 
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zeke
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Thu Nov 01, 2018 5:51 pm

sandyb123 wrote:
Out of interest, is Lion air SOP to have the departure manually flown or am I misunderstanding the data.

If the flight was being flown by the flight director / autopilot then the aircraft would I assume automatically compensate increased speed due to altitude loss with the engine throttle and even the speed brake? These overspeed events in the flight before and the ill fated flight would not have happened?

RIP to all involved.

Sandyb123


I have managed to filter about 98% of the data that you are seeing in the internet relating to the flight path. There were a lot of rubbish points in there and multiple points at the same location. This is just a limitation on how they data is transmitted and received.

When I filtered the data some of the extreme rates that we saw plotted by others are just invalid points.

The main way I filtered the points was to calculate the distance and track between waypoints. I was also able to calculate the difference in the millisecond timestamps. We have the gps ground speed, altitude, track, and time. Using Pythagorean’s between the delta in distance and altitude dividing that by the delta millisecond time stamp I get velocity, I also have track and distance. The data resolution is about 30-100 meters between points, some larger gaps where data has been filtered out.

Some of the waypoint jumped 4km behind the aircraft, and have speeds and tracks that are too far off from the GPS data. These are easy to discount as being invalid.

My observation is the flight path is chaotic, it is not smooth like I would expect an autopilot to control, based upon that I think it was hand flown.

There is a few sudden changes in direction to the left, which may or may not indicate a wing drop.

The “level” segment at 5000 ft ish has a slight left corkscrew trajectory to the flight path.

The terminal dive was in a left turn.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
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trpmb6
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Thu Nov 01, 2018 6:12 pm

zeke wrote:

I have managed to filter about 98% of the data that you are seeing in the internet relating to the flight path. There were a lot of rubbish points in there and multiple points at the same location. This is just a limitation on how they data is transmitted and received.

When I filtered the data some of the extreme rates that we saw plotted by others are just invalid points.

The main way I filtered the points was to calculate the distance and track between waypoints. I was also able to calculate the difference in the millisecond timestamps. We have the gps ground speed, altitude, track, and time. Using Pythagorean’s between the delta in distance and altitude dividing that by the delta millisecond time stamp I get velocity, I also have track and distance. The data resolution is about 30-100 meters between points, some larger gaps where data has been filtered out.

Some of the waypoint jumped 4km behind the aircraft, and have speeds and tracks that are too far off from the GPS data. These are easy to discount as being invalid.

My observation is the flight path is chaotic, it is not smooth like I would expect an autopilot to control, based upon that I think it was hand flown.

There is a few sudden changes in direction to the left, which may or may not indicate a wing drop.

The “level” segment at 5000 ft ish has a slight left corkscrew trajectory to the flight path.

The terminal dive was in a left turn.


This seems to correlate well with what the fishermen were quoted as saying.

AVHerald wrote:
On Oct 31st 2018 a local fisherman reported they (he and his friends) were out on the Java Sea to fish for shrimps when they observed a white airplane with an orange pattern in some distance, the aircraft was flying unusually low. The aircraft appeared to roll in for a turn when it shook and swooped sharply and impacted the waters of the sea. Immediately after a sound of thunder or explosion occurred. They were afraid of approaching the source of the sound and decided to return to the coast which was about 3 hours away.


Also from Avherald, it is being reported that:

AVHerald wrote:
On Nov 1st 2018 the airline confirmed one of their maintenance engineers was on board of the aircraft during the accident flight. This was an "anticipatory measure" in the event of technical problems with the new aircraft. As such, "the presence of the technician has nothing to do with the condition of the aircraft before taking off."
 
PlanesNTrains
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Thu Nov 01, 2018 6:28 pm

zeke wrote:
sandyb123 wrote:
Out of interest, is Lion air SOP to have the departure manually flown or am I misunderstanding the data.

If the flight was being flown by the flight director / autopilot then the aircraft would I assume automatically compensate increased speed due to altitude loss with the engine throttle and even the speed brake? These overspeed events in the flight before and the ill fated flight would not have happened?

RIP to all involved.

Sandyb123


I have managed to filter about 98% of the data that you are seeing in the internet relating to the flight path. There were a lot of rubbish points in there and multiple points at the same location. This is just a limitation on how they data is transmitted and received.

When I filtered the data some of the extreme rates that we saw plotted by others are just invalid points.

The main way I filtered the points was to calculate the distance and track between waypoints. I was also able to calculate the difference in the millisecond timestamps. We have the gps ground speed, altitude, track, and time. Using Pythagorean’s between the delta in distance and altitude dividing that by the delta millisecond time stamp I get velocity, I also have track and distance. The data resolution is about 30-100 meters between points, some larger gaps where data has been filtered out.

Some of the waypoint jumped 4km behind the aircraft, and have speeds and tracks that are too far off from the GPS data. These are easy to discount as being invalid.

My observation is the flight path is chaotic, it is not smooth like I would expect an autopilot to control, based upon that I think it was hand flown.

There is a few sudden changes in direction to the left, which may or may not indicate a wing drop.

The “level” segment at 5000 ft ish has a slight left corkscrew trajectory to the flight path.

The terminal dive was in a left turn.


Thank you for sharing all that.
-Dave


MAX’d out on MAX threads. If you are starting a thread, and it’s about the MAX - stop. There’s already a thread that covers it.
 
D L X
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Thu Nov 01, 2018 7:00 pm

zeke wrote:

Geebus. That sounds terrifying.

Zeke, looking at the track of the plane, they never actually turned back toward CGK. What do you make of that fact that they flew away from CGK for probably around 5 minutes after receiving clearance to return?
 
flybucky
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Thu Nov 01, 2018 8:41 pm

mzlin wrote:
I'm going to go out on a limb and guess the captain's side airspeed fault that occurred in the previous flight was not corrected, and that the pilots failed to follow proper procedure for unreliable airspeed, which is to use the proper pitch and power to maintain flight (something pilots are supposed to know for each aircraft) rather than respond to any warnings or airspeed indicators (similar to AF447).

I agree that is a likely scenario given the info that we have currently.
 
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Starlionblue
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 12:27 am

D L X wrote:
zeke wrote:

Geebus. That sounds terrifying.

Zeke, looking at the track of the plane, they never actually turned back toward CGK. What do you make of that fact that they flew away from CGK for probably around 5 minutes after receiving clearance to return?


The first priority is to "fly the airplane", and the first part of that is to achieve a stable flight path. In this case, it seems they couldn't stay straight and level. If you can't maintain straight and level you probably shouldn't attempt manoeuvres since you can't expect to turn in a predictable fashion.

1. Aviate - stabilise the flight path, then troubleshoot/fix the issue.
2. Navigate - turn back to CGK.
3. Communicate.

Aircraft which need to turn back typically will not immediately start an approach. In some cases, notably uncontrollable smoke/fire, staying in the air for longer than absolutely necessary is a bad idea. If the situation is stable, on the other hand, it is better to spend an extra 10-20 minutes in a hold preparing than to rush into the approach.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Passedv1
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 5:23 am

HappyKasper wrote:
mzlin wrote:
A Boeing flight magazine reviews these procedures in summary form (this is not a manual, but a magazine; I'm sure there are more detailed sources available): http://www.boeing.com/commercial/aeroma ... tonly.html


The accident case studies in the above link (near the bottom of the linked page) have a lot of parallels with the accident flight - two in particular sound like a very similar profile, with a crash occurring shortly after takeoff. In all cases, airspeed instruments disagreed between the captain and first officer - leading to massive confusion as one bank of instruments showed a stall and the other an overspeed.

This one's a particularly eerie parallel given the fatality count...

In February 1996, a Boeing 757 crashed after takeoff from the International Airport of Puerto Plata, Dominican Republic. After climbing through 7,300 ft, the airplane descended until it crashed into the Atlantic Ocean about 5 mi off the coast of the Dominican Republic. All 189 people on board were killed, and the airplane was destroyed.


JT610 could've been in VMC, and while altitude is easy to determine in VMC, airspeed, in particular airspeed over an ocean, might not be - particularly with a simultaneous stick shaker and overspeed clicker going off.


Aeroperu 603 FDR recording if you have never heard it gives you a good idea of how confusing it can be for the pilots with this malfunction. If you only listen to part of it, listen to the last 3 minutes or so. They have many contradictory warnings going on that you end up not listening to any of them.

https://www.youtube.com/watch?v=oZIjh7d7JmQ
 
Passedv1
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 5:36 am

spacecadet wrote:
flightless wrote:
A couple questions:
1) Since the conditions of the prior flight may be able to shed some light on the incident, I'm wondering: will the FDR and CVR have data covering that flight also?
2) There seem to be questions of the accuracy of the ADS-B data; would the plane still have been in primary radar coverage from Jakarta that could serve as a cross-check of the reported data?


#2) Primary radar coverage is far *less* accurate than ADS-B data.



Not if the airplane is having airspeed/altitude indication problems.

I think he means secondary radar, but in any case the ground speed readouts calculated from primary or secondary coupled with winds aloft at the time of the accident should be able to give you a pretty good indication of their speed.
 
spacecadet
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 5:43 am

mzlin wrote:
I'm going to go out on a limb and guess the captain's side airspeed fault that occurred in the previous flight was not corrected, and that the pilots failed to follow proper procedure for unreliable airspeed, which is to use the proper pitch and power to maintain flight (something pilots are supposed to know for each aircraft) rather than respond to any warnings or airspeed indicators (similar to AF447).


I always want to give pilots (who have just died, remember) the benefit of the doubt, which is why I danced around this earlier. But yes, when I was pointing out how a pitot tube doesn't cause a crash in what sounds like VFR conditions, what I was implying was that if they did crash due to bad airspeed and/or altitude data, pilot error seems pretty likely as the root cause.

The Aeroperu accident referenced just above took place in totally different conditions. The same procedure applies, but they had no outside reference points and never identified the problem. And given that this plane seemed to have a similar problem on the previous flight *and* an engineer was on board presumably for just this reason, the pilots in this case would have known what the issue was. (Or should have.)

I still find it strange that the crew in this accident seemed to be hand flying and maintaining 5,000 feet reasonably well, then suddenly plummeted into the ocean. For one thing, that suggests that their altimeter *wasn't* giving them faulty data (suggesting the pitot tube but not the static port was blocked), and/or that they were maintaining altitude visually - but that's pretty hard to do. (Contrast that with the Aeroperu accident, which was all over the place.) I just don't know what could be responsible for that last turn into the ocean. 5,000 feet is also not too low to recover from most upsets - unless it was a high G rollover and they couldn't reach the flight controls.
I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
 
mzlin
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 6:03 am

spacecadet wrote:
I still find it strange that the crew in this accident seemed to be hand flying and maintaining 5,000 feet reasonably well, then suddenly plummeted into the ocean. For one thing, that suggests that their altimeter *wasn't* giving them faulty data (suggesting the pitot tube but not the static port was blocked), and/or that they were maintaining altitude visually - but that's pretty hard to do. (Contrast that with the Aeroperu accident, which was all over the place.) I just don't know what could be responsible for that last turn into the ocean. 5,000 feet is also not too low to recover from most upsets - unless it was a high G rollover and they couldn't reach the flight controls.


My guess would be that they executed a left banking turn to return to the airport with inadequate airspeed and then stalled, similar to the 2010 C-17 crash or the 1994 B-52 crash.
 
sbrunei
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 11:47 am

 
estorilm
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 2:47 pm

SO many crashes and incidents lately are in some way related to unreliable airspeed, pitot static failures, etc..

MANY (if not all) have significant issues and failures leading to the events, but aviation safety has always been about removing that "link" in the chain which causes the highest number of failure events to continue towards tragedy.

With this in mind (and I was just having a conversation with someone about this the other day) I can easily see AoA sensors and some sort of integration into PFD to provide a SIMPLE visual method for safe flight in the event of any of these failures to become a top priority and requirement for future / new aircraft. The pile of incidents that would be directly impacted and potentially altered by this technology is growing quickly. Reminds me of TCAS and GPWS incidents before those systems were installed - and look how much safer aviation has become in the wake of those technologies.

Like it or not, Airbus' progressive implementation of AoA sensors over the past decade - leading directly to their BUSS / Back Up Speed System, directly solves these problems. Yes - pitch/yaw memory is key, but if every pilot was perfect, we would never be talking about these accidents. Likewise, I could point to a number of incidents where such a system would have likely saved the aircraft. I'm not pointing fingers, but Airbus did "see the light" a while ago. I personally think it's one of the most underrated safety features and systems to be created over the past decade or so. This really isn't a possibility for (even future build) *legacy* Boeing products as I understand it, due to other required sensors/systems, but I believe it's an option on all production Airbus, and standard on some.

I think it needs to be looked at as a requirement for new model certifications.
 
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ikolkyo
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 2:55 pm

sbrunei wrote:


That video before boarding is a Lion Air 737-800, not a MAX 8.
 
MEA-707
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 3:08 pm

sbrunei wrote:

True video this time but the Lion Air 737 at 1:18 is an older 737-800. The registration more looks like PK-LJP , and the LQP had titles "737-MAX 8" titles instead of "737-800" so probably they were bused to another aircraft. It are probably actual passengers of the disaster flight though, the boarding pass looks genuine.
nobody has ever died from hard work, but why take the risk?
 
trent768
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 3:12 pm

I suggest to not take any articles/videos/whatever from detik.com or tribunnews.com seriously. They were those type of paid by click news site and will do anything to earn as much clicks as possible, thus the sensational title and misinformation. Now they are bashing JT for leasing the plane from a Chinese lessor, capitalizing on the high tension against China that was built by the opposition and the radicals.

Pretty cancerous situation I must say...
 
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Erebus
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 4:32 pm

estorilm wrote:
SO many crashes and incidents lately are in some way related to unreliable airspeed, pitot static failures, etc..


There is some on-going research in the use of optical methods to measure air data (TAS, AoA etc...) as an alternative to pitot tubes, AoA probes. Here's a research report if you are interested in knowing more. Airbus and Thales are among the many participants in that project. Hopefully someday, it will result in safer and more reliable systems for this purpose.

https://reports.nlr.nl/xmlui/bitstream/handle/10921/470/TP-2012-068.pdf?sequence=1
 
Trin
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 5:11 pm

spacecadet wrote:
mzlin wrote:
I'm going to go out on a limb and guess the captain's side airspeed fault that occurred in the previous flight was not corrected, and that the pilots failed to follow proper procedure for unreliable airspeed, which is to use the proper pitch and power to maintain flight (something pilots are supposed to know for each aircraft) rather than respond to any warnings or airspeed indicators (similar to AF447).


I always want to give pilots (who have just died, remember) the benefit of the doubt, which is why I danced around this earlier. But yes, when I was pointing out how a pitot tube doesn't cause a crash in what sounds like VFR conditions, what I was implying was that if they did crash due to bad airspeed and/or altitude data, pilot error seems pretty likely as the root cause.

The Aeroperu accident referenced just above took place in totally different conditions. The same procedure applies, but they had no outside reference points and never identified the problem. And given that this plane seemed to have a similar problem on the previous flight *and* an engineer was on board presumably for just this reason, the pilots in this case would have known what the issue was. (Or should have.)

I still find it strange that the crew in this accident seemed to be hand flying and maintaining 5,000 feet reasonably well, then suddenly plummeted into the ocean. For one thing, that suggests that their altimeter *wasn't* giving them faulty data (suggesting the pitot tube but not the static port was blocked), and/or that they were maintaining altitude visually - but that's pretty hard to do. (Contrast that with the Aeroperu accident, which was all over the place.) I just don't know what could be responsible for that last turn into the ocean. 5,000 feet is also not too low to recover from most upsets - unless it was a high G rollover and they couldn't reach the flight controls.


Pretty much my contemplation in a nutshell, here. For all the talk about pitot tube issues, unreliable airspeed indicators etc., the possibilities of spatial-D etc. - there are two big discerning differences with this Lion Air flight. 1) flight was during daylight in fine weather/visibility (except if in some of the scattered clouds), and 2) flight only topped out at 5,000ft.

It is possible that the combination of those two discerning factors holds some of the answers, also. True, block pitots and unreliable airspeed should NOT lead to the aircraft crashing.......assuming the pilots have the ability to see where they are have some visual references. If AF447 had occurred during the daytime, it is entirely possible that the pilots would have been able to at least descend to below the cloud deck and ascertain their heading (or at least NOTICE their altitude when they did break out below the cloud deck.....as that flight had a real issue not noting their altitude). The PF took that aircraft up to 38,000ft before they stalled - and even after the stall they had sufficient altitude to aviate, troubleshoot, and hopefully recover stable flight. A big compressing factor was the fact that the plane was in pitch dark over ocean.

With Lion Air - we have quite the different set of factors. Yes, the flight occurred in the daylight. However, as opposed to AF447's pitot/unreliable airspeed issues (which did not manifest themselves until several hours into the flight and began at cruising altitude of 35,000ft), Lion Air's (potential) airspeed issues seem to have either occurred seconds after takeoff or were already in existence at takeoff (I am unfamiliar with how lack of airspeed indication would affect a takeoff or how much of a chance to abort takeoff the PF would have if he became aware of the issue during their takeoff roll). As I mentioned before, if pitot/unreliable airspeed was the triggering factor to this incident, it is easy to see how the crew could immediately become overwhelmed given their already necessarily low altitude (just having taken off). With such little altitude and the fact that the flight was not yet at a stable heading/cruise, these poor pilots had SUCH little time to react to anything going wrong.

We all know the insidious nature of issues resulting from lack of airspeed. However other things to consider for this flight would be the fact that they were still readily in communication with the tower, presumably on radar still, and should have had the benefit of natural horizon in the daylight. We should probably be suspicious of other mechanical issues given those factors.

Trin
 
kalvado
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 6:34 pm

Erebus wrote:
estorilm wrote:
SO many crashes and incidents lately are in some way related to unreliable airspeed, pitot static failures, etc..


There is some on-going research in the use of optical methods to measure air data (TAS, AoA etc...) as an alternative to pitot tubes, AoA probes. Here's a research report if you are interested in knowing more. Airbus and Thales are among the many participants in that project. Hopefully someday, it will result in safer and more reliable systems for this purpose.

https://reports.nlr.nl/xmlui/bitstream/handle/10921/470/TP-2012-068.pdf?sequence=1

First of all, I suggest that you put it in its own thread, possibly in tech/ops. Material well deserves it.
Second - this is positioned as a standby instrument set; I assume because they do not measure pressure - aka altitude; nether IAS - and as far as I understand that is more important than TAS being measured. Although conversion can probably be done with static pressure data - which is less vulnerable than pitot...
 
JAAlbert
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 7:32 pm

In the first few pages of this post, folks were discussing an elevator problem, but recent reports in the media are discussing the pitot tubes and altitude sensors as being suspect. Has the consensus changed? It seems shocking to me that the pitot tubes would have malfunctioned under the circumstances of the flight (aside from wasps building a next inside one of them). I am very interested to hear what the investigators will reveal. When will the FDR data be reviewed?
 
Passedv1
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 8:39 pm

estorilm wrote:
SO many crashes and incidents lately are in some way related to unreliable airspeed, pitot static failures, etc..

MANY (if not all) have significant issues and failures leading to the events, but aviation safety has always been about removing that "link" in the chain which causes the highest number of failure events to continue towards tragedy.

With this in mind (and I was just having a conversation with someone about this the other day) I can easily see AoA sensors and some sort of integration into PFD to provide a SIMPLE visual method for safe flight in the event of any of these failures to become a top priority and requirement for future / new aircraft. The pile of incidents that would be directly impacted and potentially altered by this technology is growing quickly. Reminds me of TCAS and GPWS incidents before those systems were installed - and look how much safer aviation has become in the wake of those technologies.

Like it or not, Airbus' progressive implementation of AoA sensors over the past decade - leading directly to their BUSS / Back Up Speed System, directly solves these problems. Yes - pitch/yaw memory is key, but if every pilot was perfect, we would never be talking about these accidents. Likewise, I could point to a number of incidents where such a system would have likely saved the aircraft. I'm not pointing fingers, but Airbus did "see the light" a while ago. I personally think it's one of the most underrated safety features and systems to be created over the past decade or so. This really isn't a possibility for (even future build) *legacy* Boeing products as I understand it, due to other required sensors/systems, but I believe it's an option on all production Airbus, and standard on some.

I think it needs to be looked at as a requirement for new model certifications.


The 737 does have direct AoA indications. Most airline do not order the option. AA is the only airline that I am aware of that does. AS has a direct AoA indication through their HUD.

All 737 NG’s+ allow the display of the Flight Path Vector which is also a display of the airplanes AoA.

Additionally, the stick shaker runs off the Alpha probes.

If this accident was in fact caused by the loss of control due to erroneous pitot/static although people will try, it is mid-guided to try to fault the airplane. Handling an airplane with an inoperative pitot/static system is basic pilot skills. This is especially true on a transport category aircraft.

A 737 has 3 completely isolated airspeed indication systems. I find it difficult to believe that all 3 failed. Then we have ground speed read outs as well as the AoA indications mentioned previously.

Finally, a 737 (any transport) has positive static and positive dynamic stability, if the pilots just let go of the controls the airplane would fly itself reasonably well especially considering they were at 5,000 feet.

The hard thing with pitot-static failures is the initial recognition of what you have. If there was a history as was here, and the fact that they got the airplane stabilized, makes the subsequent loss of control inexcusable to me barring some additional factor.
 
spacecadet
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 9:31 pm

JAAlbert wrote:
In the first few pages of this post, folks were discussing an elevator problem, but recent reports in the media are discussing the pitot tubes and altitude sensors as being suspect. Has the consensus changed?


I don't think there ever was consensus before, just a lot of different theories, a couple of which seemed to fit some of the facts better than others.

But now there's been confirmation that the previous flight had a problem with airspeed and/or altitude indicators (not sure if both or not), which was apparently cleared well enough in flight for the pilots of that flight to continue to their destination. There, the plane was apparently repaired according to documented procedure to fix the problem. But it seems too coincidental that the very next flight would then crash with circumstances that more or less could fit an unreliable airspeed situation. It seems more likely that the problem was not actually fixed, or possibly was even made worse.

One thing I just realized, for anyone who can answer this question... the ADS-B data we see on sites like FlightAware would be coming from the same raw data as the pilots are seeing, right? So the 300+ knot airspeed in those charts and graphs would be the faulty data they may have been seeing? That would probably mostly explain a final turn and stall into the ocean...
I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
 
mxaxai
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 10:27 pm

Trin wrote:
However, as opposed to AF447's pitot/unreliable airspeed issues (which did not manifest themselves until several hours into the flight and began at cruising altitude of 35,000ft), Lion Air's (potential) airspeed issues seem to have either occurred seconds after takeoff or were already in existence at takeoff (I am unfamiliar with how lack of airspeed indication would affect a takeoff or how much of a chance to abort takeoff the PF would have if he became aware of the issue during their takeoff roll)

Trin

This is an interesting point. The "unreliable airspeed" theory makes sense, but why did the issue only occur on the initial climb? The PM would have been monitoring the airspeed during the takeoff roll and any fault should have been caught right there. Aren't the call-outs "80", "100" and "V1" standard for any pilot, at any carrier? And doesn't the system already check for airspeed disagreement? So something like forgetting the pitot covers would be detected quickly.

What could allow the pitot tubes to work well on the ground, but causes them to fail quickly after getting airborne?
 
many321
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Fri Nov 02, 2018 11:48 pm

Haunting to see the that footage from the wreckage, especially that moment were a section of the screen is blurred implying a person's body part. Rest in power for those who passed on.
 
tcfc424
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 5:11 am

So there's a lot of focus on the unreliable airspeed possibility. That said, and not saying that was a factor in this incident...there's a RAT that can be deployed to generate power in the event of a complete electrical failure...why would it not be possible to have an emergency Pitot deploy in the case of an airspeed disagree? This would essentially be a pitot tube that was protected from the elements, inspected at specific intervals, and would only be engaged in cases of an airspeed disagree. Maybe I don't understand the mechanics and logistics of a pitot tube (perhaps needing to be rigid and unable to be "deployed") but it seems even an emergency pitot tube would be better than nothing?
 
mandala499
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 6:04 am

Finally I can get a day of rest... so here goes...

kanban wrote:
The BBC piece noted above contains the following:
"Aviation consultant Gerry Soejatman told the BBC the MAX 8 had been experiencing problems since it was introduced, including problems maintaining a level flight"

never heard of this problem or do we just have a troll looking for 30 seconds of notoriety???

It was a misquote.
I remember specifically that I said, "this flight seemed to have problems in maintaining a smooth straight and level flight".

That morning I was woken up by a call from my friend who told me about the crash. I immediately looked at FR24's data and thought, "this looks like an air data problem" (Don't ask me how I 'guessed' that, but seeing the filled out version of maintenance log reaching my phone within a few hours surely gave me a chill down my spine).

As soon as I put the phone down, the BBC called me.
Sorry, am not a troll looking for 30 seconds notoriety.

I can't remember which journo called me from the BBC and made that quote. I just chatted to another one I know from the same office who called me that day, she seems to remember that I also said what I meant was the specific flight in question and not the type in general. Hopefully the misquote can be corrected on monday. We'll see..

Erebus wrote:
Does anyone know anything more on what he is talking about here? Or is it a case of media misreporting where he could have been just referring to the accident aircraft's ill-fated flightpath.

It happens... sadly :(
Unfotunately, some people are just too salty about it.

CrimsonNL wrote:
I haven't heard of these problems either, but I can assure you Mister Soejatman is not a troll.

Thank you. Those who know me personally here, do know me!

afterburner wrote:
He also used to be an active member of this forum.

I still come here from time to time. :)
This is a place where I started my obsession with technical issues of airplanes. It is one of my "roots"...

cpd wrote:
If that is a forum member on this board, then hopefully he'll explain himself.

And here I am. Explained above.

I was inundated by calls from the airline, other airlines, the NTSC, the DGCA and countless media calls that day that I simply couldn't get back to the BBC to tell them early on about the misquote.

jcancel wrote:
What I don't understand is how the Indonesian government didn't know that AirAsia Indonesia was flying that route without permission..."

The airline, the competitors, the airport, and the ATC are also still asking that question to this day. Without permission the slot wouldn't have been allocated. The airline's appeal seems to have been ignored. I have heard that the then minister was basically launching a personal vendetta as one of his friends was onboard, however, no one is willing to go on record on this.

CrimsonNL wrote:
Boeing's legal staff would be busy if they are suing everyone who's critical of their products.

Boeing actually has my phone number. :) They can call me for an explanation.

LAXLHR wrote:
I REFUSE to get on Lion Air, with their 18 year old pilots.

Me too... not because of their safety, but their passengers, are just too damn scary for me... I hate being on the same boarding gate as their flight. :(

airkas1 wrote:
And to debunk the people questioning Gerry for his quote regarding this crash: https://twitter.com/GerryS/status/1056847635062054912
I've always considered him a good and reliable source as well.

Geez, thanks for that. As I was reading this topic this morning for the first time since the crash, the inundation surrounding this event made me forget that had posted that earlier. Lack of rest I guess...

dtw2hyd wrote:
His initial conclusions without root cause analysis are always wrong. But he is a one-man show, dines with aviation minister and on TV critique of government and consultant to everyone.

Which minister? The one during the Air Asia crash?
Just so that people don't get the wrong idea, for public record, to this date, I have not dined with any Indonesian transport minister. :)
And yes, when I'm wrong with an analysis, please do so say so. It's never a sin to criticize someone objectively. It makes us all better :)

bolbibug wrote:
https://news.detik.com/berita/d-4278530 ... -penumpang

A passenger on the same plane the night before from Denpasar Bali to Jakarta has the following story to relate regarding her flight:

- Late boarding, scheduled 6.15pm to 7.30pm
- During wait for puchback, ac shuts off intermittently
- Plane pushed back, heading to runway, experienced technical issue and return to gate, no explanation
- Stayed at gate about 30 minutes, ac shut down, very hot cabin conditions (children throwing up), no explanation
- Some passengers forced door to open to deplane (due to intolerable conditions without ac)
- Ground crew as confused as passengers, a ground crew admitted bad coordination with Lion Air plane crew
- Passengers asked to return to plane for engine checking
- Announced that take off would proceed
- 10 minutes after announcement, plane still at gate, with cabin light power flickering on and off
- Eventually taxied to the runway for take off
- Unusual right engine noise, as if it is working extra hard and surging constantly all the way from denpasar to jakarta
- Landed safely in jakarta

This has been proben to be false. Some tv personality or so, posted that on her social media, only for planegeeks to point out to her that her aircraft was not PK-LQP. She did not fly on JT043 but on JT033 (if I remember correctly) and that her aircraft was a 737NG not a Max. She has since apologized publicly for that.

Only mistakenly? Or intentionally too? Could the flight data we've seen show some kind of in-cockpit-struggle followed by a intentional dive?"

OMG! This is too soon for this for speculation... come on!
I've talked to those who knew both of the pilots, and also a former training captain at the airline. His description of their characters while does not rule out any potential CRM breakdowns, does not make "intentional dive" as a likely cause. However, this is a.net...

1989worstyear wrote:
I'm unfamiliar with the millenial-era 737's and this system, but would an altitude and IAS disagree really impact the trim?

I believe the pitch control system remains the same. Indicated airspeed comes from the Pitot-Static system through the ADR and onto the displays. There is however, an elevator feel computer or a feel computer that covers all primary control surfaces, which has it's own pitot system separate from the ones the rest of the aircraft use, and that if I remember correctly provides an artifical feel (simulating wind resistance) on the control yoke. If so, an unreliable airspeed would make the yoke resistance forces "feel" out of place. That's probably why we see the FEEL DIFF PRESS (or something) in the maintenance log.

DocLightning wrote:
So the actual actuator system for the elevator didn't change? Because an elevator issue could be one possible explanation for the observed data, no?


LTC8K6 wrote:
2. The second is related to the dynamic air pressure supply to the Elevator Feel Computer. It receives dynamic pressure from the two pitot tubes mounted on either side of the vertical stabilizer. When the computer receives an eratic signal it’d be the same as the pressure drop and the light illuminates. (failed probe heater and icing conditions)
3. The third is related to the Stall Management and Yaw Damper (SMYD), and a so called Elevator Feel Shift module (EFS), which creates a ±4 times higher forward control column force when approaching the stall region. This force uses a reduced system A pressure and when this reducer fails, opening prematurely providing a higher than normal A system pressure to the feel actuator, the FEEL DIFF PRESS also illuminates after 30 seconds.

Aha!!!! Thanks for this... was looking for this a while back. That point #3, is quite worrying. I'm trying to dig into my sources here because I heard the AOA vane may have been replaced the day before or something like that... still trying to get confirmation.

dragon6172 wrote:
GS probably comes from a GPS source, or FlightRadar24 calculates it based of time/distance of position data.

GS speed is from onboard GPS source and transmitted by the aircraft.

mxaxai wrote:
There is a problem in Indonesian aviation but it is not confined to any airline in particular. The EU blacklisting of all Indonesian carriers shows that. And when aviation seems bad, don't even think of stepping foot on an indonesian road or boarding a ship. I've done that and never feared more for my life. I would still happily fly Lionair (not Sriwijaya Air though - too much duct tape for my taste).

The problem was real. We are now dealing with the remnants of the problem a the EU blacklisting has been lifted recently. And yes, the roads and ships here... no no for me...
I don't fly LionAir, not because of safety, but because their passengers are too damn scary! I really wouldn't want to be in an aircraft incident with them, let alone an accident. If I fly a LionAir group aircraft, I stick to BatikAir.
Sriwijaya? Too much duct tape? Finally I have someone in a.net who has also seen too much duct tape there at sometime in our lives! :)

Starlionblue wrote:
Also, GPS without air data will give you ground speed, not IAS. Much better than nothing of course.

There are conflicting reports that the crew either asked "what's our/my speed" to ATC or asked "what's our/my groundspeed" to ATC... I hope the latter....

Starlionblue wrote:
Pilot training and knowledge are the deciding factors.

LCC or not, Indonesia or not... THIS is absolutely correct, and limited to pilots, but also all persons with a safety role, no matter how small.

HappyKasper wrote:
What I was interested in here is airspeed - since the ADS-B data only shows groundspeed, I plotted that in blue, and then took the square sum (sqrt(a^2 + b^2)) of the groundspeed in knots and vertical speed in knots to find an approximate airspeed in KTAS, assuming still air. That's plotted in grey. It shows an estimated airspeed of 472 KTAS at the time of the final ADS-B return.

Ah, this is what've been looking for! Thanks :)
Not a nice number.

frmrCapCadet wrote:
Eye witnesses are important in any investigation. They are often accurate. What an eye witness should not do is reconstruct what they saw. "Just the facts, ma'am" Skilled investigators are able to take disparate eye witness data, assess its likely quality, and put it into context. And note: the fishermen are not explaining why the plane crashed, they are simply stating what they saw. Useful, but not infallible data.

Being in an air-accident prone country, one thing I've learnt about air accidents in Indonesia: 90% of witnesses who try to make it to the media, are liars!
However, the less descriptive and less fantastic the statement, usually, the more correct they are. Fantastic as in sensationalistic...
This two fishermen's statement does not come unto the Indonesian "sensationalistic statement", so it makes sense... albeit I think there's a mistranslation. What I heard about these 2 fishermen is that they saw the plane hit the water first, then hear the sound. Which makes sense.

gia777 wrote:
My trust only with Garuda Indonesia - Citilink - Sriwijaya (yes). These 3 airlines you can count on them. As for Batik Airlines, they are still under Lion Group. Regardless what happened to the Lion accident, still, there is no excuse that the plane suffered technical issues the day before and they did not perform the repair for whatever reason 100% otherwise the accident will not occurred. Sure, they could say they performed the safety check under boeing guidelines...but who knows? Just like Adam Air, they notorious in cheating the safety check. Of course the Lion Air management will say we did the repair and the plane was good to go. Like hell they gonna say...yes we flew the broken plane. The amount compensation given by the Lion Air also a joke... $500 per passenger for burial process and $1000 for immediate cash relief and $5000 for accident compensation. I still can't believe the government did not shut down this airlines long time ago. If Qantas never involved in accident means they have a very solid system in safety check. So again there is no excuse for this accident. Avoid Lion at all cost!

1. You don't know what they did to the airplane the day before. You won't have a clue.
2. One of those 3 airlines above there I wouldn't even want to touch let alone get on board unless I really really have to. I know too many people who told me how things work there (not just the haters, but those who somehow love the company), and you putting it in that list, to me strengthens my view on point #1.
3. $5000 for accident compensation? That's the IMMEDIATE compensation. The total is much much larger (over 1 Billion IDR according to the government regulation on air accident compensation).
Never say never. Solid safety checks are just quality assurances and not absolute assurances. There are no absolute assurances that air accidents will not happen to an airline (no matter how good), except for grounding the airline.

gia777 wrote:
Lion Air Group just fired their Director Technical Operation today

Let me correct you on this: Lion Air Group has temporarily relieved Lion Air's Director of Engineering to assist the investigation process and has put in a temporary replacement.
That guy who was "grounded" has only been on the job for a few weeks. His previous job was Director of Engineering at Batik Air.
The reason why people think he got fired is because the media misunderstood what the minister said... he said "temporarily relieved of duty", and the media quoted "terminated". It got so out of control that a few hours later the ministry has to make a press conference to clarify what the minister actually said (Which one media who paid attention, got correctly)... What a waste of time for the ministry... :(
The airline, spooked by the previous transport minister's reaction on the previous accident (who basically ended up being a megalomaniac dictator on how the accident was handled), made the wrong press release statement too.
Sad... We worked hard as hell up to 2014... our accident rates were still going down, even with that accident in 2014... and one person's reaction, changed all that, and basically blew over 5 years of hard work by the industry in implementing safety management systems, just culture and no-blame environments, etc, into an environment where submitting a safety report can lead to dismissal or punishment for "wrong doing"... by the government... We do not want to go back to those dark days where safety management system was secondary to public appeasement!

Starlionblue wrote:
Even assuming perfection is possible can lead to hubris.

It leads to accidents...

hayzel wrote:
you can see the terrible CRM and state of training for pilots in the Lion Air Group(this guy is employed by Batik Air). In some videos when the FO is PF and the Captain is PM, he retracts flaps etc. without any callout from the FO. Even worse, in one of the videos when the FO is PF on the landing, they forgot to arm the spoilers. The captain notices right on touchdown and manually pulls the lever and laughs about it. Terrible, absolutely terrible

It appears that many people can't wait for this guy to retire. Btw, he's in Lion Air, not Batik Air.

gia777 wrote:
Any maintenance that involves air speed indicatior altitude, primary flight system or major parts of the plane, a test flight must be performed. Changing light bulbs? no need test flight. Use common sense.

No, not even your beloved (and may I say, loss-making) Garuda does that unless the manuals say so.
Use your common sense. Go and obtain an aircraft's approved troubleshooting manual, MEL, and AMM... then we can talk. :)

trin wrote:
Pretty much my contemplation in a nutshell, here. For all the talk about pitot tube issues, unreliable airspeed indicators etc., the possibilities of spatial-D etc. - there are two big discerning differences with this Lion Air flight. 1) flight was during daylight in fine weather/visibility (except if in some of the scattered clouds), and 2) flight only topped out at 5,000ft.

Fine weather was near the airport. I live a west of HLP/WIHH airport, and the airplane flew some 8NM from my house. At 9AM it was cloudy with BKN to OVC over my house and to the northeast and southeast... I suspect it would have been cloudier in the morning... Unfortunately, I don't know how high the cloud tops were... But to me, there is always a possibility that the aircraft entered IMC from time to time. We'll have to wait though...




Other updates:
Yesterday I had enough with politicians trying to get the spotlight in this accident. A member of parliament went on radio yesterday to criticize the SAR agency for "moving too slowly" and saying that "collecting airplane debris instead of bodies / bodyparts is a waste of public funds"... In disgust, the radio station put me on air within 5 minutes and I almost lost my temper... :( And then this morning, this morning, we lost one SAR diver due to decompression :( :( RIP.

If I see that member of parliament I might end up getting arrested for assault and battery!
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
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Erebus
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 6:32 am

Good to see you on again mandala499. As always, I welcome your insightful commentary.
 
juliuswong
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 6:39 am

Nice to see you back again Mandala499. Always welcome your inside information.

PS. Knowing how Malaysian Government bungled up MH370 handling, I won't be surprised same thing is happening to JT610. Both countries shared some out of this world management style. There are a lot of YouTube now showing reporters diving into crash sites, collecting debris on sea floor! RIP all crew and pax.
- Life is a journey, travel it well -
 
icywings11
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 8:57 am

Where can I download or view the tech log people are talking about? Thanks!
 
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AlexA340B777
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 9:21 am

Welcome back / selamat datang kembali Pak mandala499,

it is good to hear from you again here and thanks a lot for your detailed post and insights.


Best regards

Alex
6 continents, 85 countries, 748 flights, 90 airlines, 37 aircraft types
 
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frigatebird
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 9:49 am

Hi Gerry, great to see you posting again. Always very interesting to read your insights.

mandala499 wrote:
this morning, we lost one SAR diver due to decompression :( :( RIP.

This is very sad indeed, in the aftermath of the crash another victim is claimed.. :(
Earlier upthread I mentioned the wreckage would be at a depth which could be reached by divers. I believe early reports said 30 metres. But I also saw other ones mentioning 50 metres. This is quite a difference in diving, 40 metres or deeper is really for the specialised professionals. My deepest dive was 32 metres.
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aandi
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 10:00 am

Interesting... According to this media, in the previous flight (DPS - CGK), the pilot declared pan pan only 5 minutes after take off and requested return. But later he cancelled it and continue to CGK.
Artcle (in Indonesian language):
https://m.detik.com/news/berita/4285337 ... -air-jatuh
 
cpd
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 10:15 am

mandala499 wrote:
cpd wrote:
If that is a forum member on this board, then hopefully he'll explain himself.

And here I am. Explained above.


I suspected a misquote, hence my caution. Thanks for posting.
 
mandala499
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 10:17 am

aandi wrote:
According to this media, in the previous flight (DPS - CGK), the pilot declared pan pan only 5 minutes after take off and requested return. But later he cancelled it and continue to CGK.

The request to return has been determined to be untrue. But... they did have unreliable airspeed / altitude, but they continued on the normal SID route, and climbed once they figured which side was giving the wrong airspeed readings, and the crew determined it was better to continue to Jakarta albeit under RVSM airspace.
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
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seahawk
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 10:49 am

Erebus wrote:
estorilm wrote:
SO many crashes and incidents lately are in some way related to unreliable airspeed, pitot static failures, etc..


There is some on-going research in the use of optical methods to measure air data (TAS, AoA etc...) as an alternative to pitot tubes, AoA probes. Here's a research report if you are interested in knowing more. Airbus and Thales are among the many participants in that project. Hopefully someday, it will result in safer and more reliable systems for this purpose.

https://reports.nlr.nl/xmlui/bitstream/handle/10921/470/TP-2012-068.pdf?sequence=1


The better question is why the pilots can simply call up the GPS measured speed. It should be fine to keep the plane in the air in most circumstances and help finding the faulty pitot.
 
Rara
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 11:34 am

spacecadet wrote:
JAAlbert wrote:
In the first few pages of this post, folks were discussing an elevator problem, but recent reports in the media are discussing the pitot tubes and altitude sensors as being suspect. Has the consensus changed?


One thing I just realized, for anyone who can answer this question... the ADS-B data we see on sites like FlightAware would be coming from the same raw data as the pilots are seeing, right? So the 300+ knot airspeed in those charts and graphs would be the faulty data they may have been seeing? That would probably mostly explain a final turn and stall into the ocean...


The data published by FR24 and others is groundspeed. It should be the same data the pilots are seeing, but it doesn't really help in regard to the question of unreliable airspeed. I haven't seen indicated airspeed readings of the flight, even though to my knowledge, ADS-B transponders should transmit airspeed as well and FR24 etc. should have it. That would certainly be helpful in narrowing down probably causes.

I've mentioned it before on this thread, but I'm still very baffled by the nose-down attitude of the plane early in the flight and indeed twice on the flight the night before. It doesn't look like much on the flight profile, but it's super unusual and it must have made a tremendous negative-G force impression on passengers and crew. Does anyone have any idea of how such a dip, for lack of a better word, could be caused by unreliable airspeed? In the initial climb, thrust and speed are fixed and rate of climb is variable. So I guess unreliable airspeed (airspeed higher than shown) could cause a nose-down attitude to regain the (seemingly) lost speed. But would an autopilot actually command a nose-down attitude? My gut feeling says the autopilot would simply disconnect. Does anyone know for sure?
Samson was a biblical tough guy, but his dad Samsonite was even more of a hard case.
 
mm320cap
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 11:35 am

mandala499 wrote:
aandi wrote:
According to this media, in the previous flight (DPS - CGK), the pilot declared pan pan only 5 minutes after take off and requested return. But later he cancelled it and continue to CGK.

The request to return has been determined to be untrue. But... they did have unreliable airspeed / altitude, but they continued on the normal SID route, and climbed once they figured which side was giving the wrong airspeed readings, and the crew determined it was better to continue to Jakarta albeit under RVSM airspace.


This absolutely floors me. From the description I’ve read about the previous flight, there were some fairly radical (unintentional) maneuvers performed while trying to ascertain the nature of the issue. I simply can’t fathom the decision to continue with an unreliable airspeed/altitude issue on one side.

I try hard not to second-guess decisions other Captains make, but I’m having heartburn with this one... especially given the UAS they experienced early in the flight.
 
Halophila
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 11:46 am

https://reports.nlr.nl/xmlui/bitstream/handle/10921/470/TP-2012-068.pdf?sequence=1[/quote]

The better question is why the pilots can simply call up the GPS measured speed. [/quote]

Amateur here, but it would probably have to be some kind of corrected GPS speed... accounting for ascent or descent angle, right?
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packsonflight
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 11:50 am

From the FR24 data it looks like the suspected airspeed problem persisted all the flight, and it begs the question if the pilot passed the 80 kt speed threshold in the takeoff roll with both airspeed indicators with matching speed.

After the AF447 crash pilot training slowly started to change (much to late) from sole reliance on none normal checklist "unreliable airspeed", to pith and power flying. This checklist is complicated and it is 4 pages long, and it is no small defeat to go through it correctly shortly after takeoff with flaps down, takeoff thrust and stalled aircraft as the FR24 data indicates happened when the aircraft reached 6000 feet.
The question is if the pilots where trained to revert right away to pitch and power flying to keep the aircraft safe, and then go to the unreliable airspeed checklist, because in a situation like this the workload is so high, and so many factors that needs your full attention on top of the startling effect that there is really no time to read through the checklist.
There is really one way to deal with situation like this, and that is pitch and power flying, the question is if the pilots where trained to trust this method.
 
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zeke
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 12:06 pm

Rara wrote:

I've mentioned it before on this thread, but I'm still very baffled by the nose-down attitude of the plane early in the flight and indeed twice on the flight the night before. It doesn't look like much on the flight profile, but it's super unusual and it must have made a tremendous negative-G force impression on passengers and crew. Does anyone have any idea of how such a dip, for lack of a better word, could be caused by unreliable airspeed? In the initial climb, thrust and speed are fixed and rate of climb is variable. So I guess unreliable airspeed (airspeed higher than shown) could cause a nose-down attitude to regain the (seemingly) lost speed. But would an autopilot actually command a nose-down attitude? My gut feeling says the autopilot would simply disconnect. Does anyone know for sure?


The nose down could be accounted for by an issue with the speed stability system which is supposed to trim out the pilot pitch feel.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
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zeke
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 12:08 pm

Halophila wrote:

Amateur here, but it would probably have to be some kind of corrected GPS speed... accounting for ascent or descent angle, right?


No ground speed is purely based upon the change in latitude and longitude
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
PA515
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 12:52 pm

mandala499 wrote:
seeing the filled out version of maintenance log reaching my phone within a few hours surely gave me a chill down my spine


On the completed copy of the maintenance log the column 'Return To Service' had the 'No' box ticked for each of the three items. What do you make of that?

PA515
 
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litz
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 4:52 pm

Regarding the maintenance log, the following is interesting reading ...

https://theaircurrent.com/aviation-safe ... ial-media/

Three different versions of the same document, apparently at different stages of being filled out.

Regarding the "Return to Service", there's another maintenance log entry shown in an incident report from another flight, which had a pressurization problem. In that document, Return to Service is also checked as No.

http://knkt.dephub.go.id/knkt/ntsc_avia ... Report.pdf
 
Tristarsteve
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 5:46 pm

[photoid][/photoid]
On the completed copy of the maintenance log the column 'Return To Service' had the 'No' box ticked for each of the three items. What do you make of that?


The box that is ticked No is the RII statement. It is not Return to Service No, but RII (Required Inspection Item) needed NO.

RII is required on certain specific maintenance items, mainly to do with control cable replacements etc. It means that an Inspector, or a mechanic with RII approval, must check the work of the first mechanic. It was not required in this instance.
The NO is correct. RII is called Duplicate Inspection in Europe.
 
lowbank
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 5:50 pm

Every days a school day.
 
lowbank
Posts: 512
Joined: Wed Mar 25, 2009 9:10 pm

Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 5:51 pm

https://www.flightradar24.com/blog/wp-c ... inutes.jpg

First 11 minutes of the day before flight.
Every days a school day.
 
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Finn350
Posts: 1601
Joined: Tue Jul 09, 2013 4:57 am

Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 5:53 pm

litz wrote:
Regarding the maintenance log, the following is interesting reading ...

https://theaircurrent.com/aviation-safe ... ial-media/

Three different versions of the same document, apparently at different stages of being filled out.

Regarding the "Return to Service", there's another maintenance log entry shown in an incident report from another flight, which had a pressurization problem. In that document, Return to Service is also checked as No.

http://knkt.dephub.go.id/knkt/ntsc_avia ... Report.pdf


It looks suspicious that there are three different versions of the same document. If the document is real at all, it looks like that the "corrective actions" has been filled in after the crash (as why would anyone photograph the document before the crash, as it was not newsworthy then).
 
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AirlineCritic
Posts: 1776
Joined: Sat Mar 14, 2009 1:07 pm

Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 5:58 pm

Good to see you commenting on this, mandala499! Thanks for the info.

And sorry to hear about further loss of life.
 
mandala499
Posts: 6599
Joined: Wed Aug 29, 2001 8:47 pm

Re: Lion Air 737MAX8 Crashed Jakarta to Pangal Pinang

Sat Nov 03, 2018 6:08 pm

frigatebird wrote:
Earlier upthread I mentioned the wreckage would be at a depth which could be reached by divers. I believe early reports said 30 metres. But I also saw other ones mentioning 50 metres. This is quite a difference in diving, 40 metres or deeper is really for the specialised professionals. My deepest dive was 32 metres.

It's 33.1m according to a member of the dive team.

mm320cap wrote:
This absolutely floors me.

You're not the only one having gastric issues over the decision. I'd certainly would like to know more about that myself.


Tristarsteve wrote:
The box that is ticked No is the RII statement. It is not Return to Service No, but RII (Required Inspeection Item) needed NO.

RII is required on certain specific maintenance items, mainly to do with control cable replacements etc. It was not required in this instance.
The NO is correct. RII is called Duplicate Inspection in Europe.

I hope this is correct, otherwise it'll be a huge mess.

Finn350 wrote:
It looks suspicious that there are three different versions of the same document. If the document is real at all, it looks like that the "corrective actions" has been filled in after the crash (as why would anyone photograph the document before the crash, as it was not newsworthy then).

I questioned this to a former LionAir captain. His explanation was quite interesting.
The unfilled version usually be taken by either one of the pilots prior to handing the matter off to engineering. They routinely take this as evidence or "bragging rights to complain" with pilot chat groups (a habit that exists here). This is a remnant of the "bad old days" when significant distrust between pilots and engineers occured...
It looks like a photo of the page being flattened by a software to look like a scan and convert it to PDF, something that is relatively popular here.
When losing situational awareness, pray Cumulus Granitus isn't nearby !

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