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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 13th Mar 2019, 06:10
  #921 (permalink)  
 
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US FAA will issue a statement, only once or US airlines will have adjusted their workload, be able to replace the MAX without losing money. Sector by sector
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Old 13th Mar 2019, 06:13
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Originally Posted by crosscust
MCAS is operational with flaps up. Most (if not all) airlines do not start retracting flaps till 3000’ AFE. According to reports, Ethiopian never achieved anything higher than about a 1,000’ (not even close to 3k).


Clearly you have never left the US and are not familiar with the various forms of noise abatement procedures used worldwide. Google NADP2 (Proc B) and you'll understand most non-US carriers worldwide routinely accelerate and commence flap retraction at >800' (NADP2) or >1000' (Proc B) above 1000' AFE.

Noise Abatement Procedures

Last edited by Dune; 13th Mar 2019 at 06:35.
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Old 13th Mar 2019, 06:23
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Originally Posted by hans brinker
Don't get me wrong, I totally agree. The 737 should stop at 150 people and 3 hours, (if B wants a bigger plane start building the 757NG.) If you have stretched your plane so far you need an extra telescoping landing gear and higher speeds to prevent a tailstrike, and software trimming because of inherent instability you are doing something wrong. If you implement said band-aid with a single source input and call it a day, you are well on your way to criminal negligence. MCAS should never have been designed, build or approved this way, my post was just a reply to someone who was more scared of software than hardware, and I disagreed with his POV.
We are still awaiting confirmation that MCAS is responsible for either crash.
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Old 13th Mar 2019, 06:25
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Originally Posted by Luc Lion
There are such switches, although they are hidden in the column.
See FCOM 9.20 "Controls - System Description" - "Stabilizer Trim".
Read also the function of the "Stabilizer Trim Override Switch"
Thanks for the correction, not on the 737 myself.
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Old 13th Mar 2019, 06:26
  #925 (permalink)  
 
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Originally Posted by Dune

Clearly you have never left the US and are not familiar with the various forms of ICAO noise abatement procedures. Google NADP1 vs NADP2 and you'll understand most non-US carriers worldwide routinely accelerate and commence flap retraction (NADP2) above 1000' AFE.

http://www.b737mrg.net/downloads/b737mrg_noise.pdf
Looks like this lad is trying to get some international experience at QR:

Originally Posted by crosscust
FMC Overheat: Was the offer for a DEC or an FO? Thanks. Just wondering what they're interviewing for.
I wish him well in his future endeavors.

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Old 13th Mar 2019, 06:37
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Iím not sure there was any suggestion this caused the latest accident- just that itís bad design.
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Old 13th Mar 2019, 06:39
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What does the data say?

Non-pilot but expert number cruncher with a basic questions about the DATA shown in post 69 and several prior to that.

Looking at the ADS-B numbers, in ascending time sequence from the start of the takeoff roll at 05:38:01Z, I see:

18 seconds with 0 elevation gain (to 7,200') and acceleration from 0 to 93 knots (ETH-302 still on the runway?)
5 seconds with 25' elevation gain (to 7,225') and acceleration from 93 to 105 knots (ETH-302 still on the runway?)
11 seconds with 00' elevation gain (to 7,225') and acceleration from 105 to 154 knots
11 seconds with 25' elevation LOSS (to 7,200') and acceleration from 154 to 183 knots (did ETH-402 try to lift off runway and then settle back on to it?)
14 seconds with 25' elevation gain (to 7,225') and acceleration from 183 to 200 knots

59-seconds after beginning the takeoff roll - the plane was at 200-knots and had gained NO altitude above the runway (based on elevation at 105-knots). Is that possible?

At 59-seconds there could not be much of the ~12,465' runway left ahead of the plane since it had been doing an average of 150-knots (250 fps) for 33-seconds (8,250') and had travelled about 3,000' accelerating in the first 26-seconds.. At what point would the takeoff be rejected? Or is this just a normal takeoff at a hot and high airport?

I assume MCAS could not have been active during the first 60-seconds of the takeoff event.

Continuing with the sequential timestamps:

50-seconds with 925' elevation gain (to 8,150') and acceleration from 200 to 263 knots.
25-seconds with 450' elevation LOSS (to 7,700') and acceleration from 263 to 323 knots.
45-seconds with 900' elevation gain (to 8,609') and acceleration from 323 to 283 knots.

From the time ET-402 reached 226-knots at 7,575' there were 33 ADS-B reports of which only 7 showed a loss of altitude and they all occurred in a 21-second period (5:39:55 to 5:40:16)

During the period 5:40:09 to 5:40:45 the plane maintained an altitude of 7,750' +25'/-50'.

From 5:40:35 to 5:41:02 (end of data) the plane climbed steadily and gained 875' while accelerating to 383-knots.

How does the data above fit with the theory of MCAS forcing a rapid descent?
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Old 13th Mar 2019, 06:41
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Originally Posted by 4runner
The 737 incurs a pitch up moment with additional thrust because of engine placement and moment. Not because of ďliftĒ. Iím glad youíre working on your multi engine ratings right now and went over vmc factors including accelerated induced flow.
I think you are replying to me but don't know how to use the quote function.
Sorry to disappoint you, but I have 5 type ratings, 10K+ hours, FAA ATP & JAA ATPL.
And as explained more clearly below MCAS has nothing to do with thrust, and everything with aerodynamics.
I suggest you read it, and let me know if you need any more help becoming less condescending.

Originally Posted by FCeng84
Hans - your patience is amazing. You are correct about the relationship between 737MAX engines and need for MCAS. It has nothing to do with the thrust pitching moment!!!

There is a cert requirement that as AOA increases, the nose up pilot command required must not decrease. This is demonstrated at fixed thrust levels so there is no change in thrust pitching moment. The 737MAX issue here that gives rise to the need for MCAS is that as AOA increases the lift provided by the engine cowling that is so large and mounted so far forward of the wing causes a nose up pitching moment that results is a decrease in the column pull needed to maintain a steady positive AOA rate. That characteristic is not compliant with the requirements. MCAS comes active during this maneuver putting in nose down stabilizer that must be countered by the column. The net effect of engine cowling lift and MCAS nose down stabilizer as AOA increases is that the column needed to complete the maneuver does not decrease part way through the range of AOA for which characteristics must be demonstrated. 737MAX without MCAS fails the cert demo. 737MAX with MCAS passes the cert demo.
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Old 13th Mar 2019, 06:50
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Originally Posted by gmx
We are still awaiting confirmation that MCAS is responsible for either crash.
We don't know about Ethiopian, but I am convinced Lion Air is directly caused by faulty AOA info to MCAS. Should the pilots have been able to recover like the ones did the day before? Probably/absolutely, but that doesn't change that the MCAS design is a major problem.
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Old 13th Mar 2019, 07:10
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Originally Posted by hans brinker
We don't know about Ethiopian, but I am convinced Lion Air is directly caused by faulty AOA info to MCAS. Should the pilots have been able to recover like the ones did the day before? Probably/absolutely, but that doesn't change that the MCAS design is a major problem.
You are likely correct about Lion, but it is yet to be confirmed. There were flight control issues on that aircraft prior to the ineffective (unwarranted?) replacement of the AoA vane.
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Old 13th Mar 2019, 07:32
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Originally Posted by hans brinker
..... If you have stretched your plane so far you need an extra telescoping landing gear and higher speeds to prevent a tailstrike, and software trimming because of inherent instability you are doing something wrong.

Well, while not exactly the same, I guess you think they better dump the 777-300ER as well due to the design features needed on that jet??
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Old 13th Mar 2019, 07:35
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Originally Posted by RatherBeFlying
By the time a MAX 8 or 9 has made it to cruise, the phase of flight that claimed Lion and ET is long past. And the pax have to land somewhere, preferably within reasonable reach of destination.
MCAS event could happen at any phase of flight. You just need: a failed AoA sensor, AP disengaged (would failed AoA disengage AP?) and flaps up.
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Old 13th Mar 2019, 07:37
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Tacoma Sailor....How does the data above fit with the theory of MCAS forcing a rapid descent?
ADSB data is not always accurate.
This data may not fit any theory yet, but there is fairly solid evidence of a rapid descent.
There is a large crater with small bits of 737Max in it.
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Old 13th Mar 2019, 07:39
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Originally Posted by 12A
Tell that to Porsche with their 911
And that, ladies and gentlemen, is complete bull****. Porsche only built the 911 from 1963 until 1989. The model that is sold today under the marketing designation 911 has zero commonality (other than styling and marketing) with the actual model 911, very much unlike the 737 MAX.
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Old 13th Mar 2019, 07:40
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Originally Posted by fox niner
With all these airlines and governments around the globe grounding their MAX fleets,,,,,,,,......And can they be read out with some priority? The world demands some reassurance.
You think ....?
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Old 13th Mar 2019, 07:43
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Time frame for CVR and data recorder analysis

I am a non professional, so grateful for any insight regarding recorder analysis. If the recorders are in a reasonable condition, I presume down loading data is like down loading from a massive USB stick. This surely must have already be done by now? As it seems that the cockpit crew were able to communicate with the tower, so there must have also been some crucial conversation between captain and first officer as well. That voice recording could quite quickly tell us what they thought was going on. What I am really asking i suppose, is how quickly, are we likely to hear a preliminary report of what happened to aircraft. For an example, if there was a terrorist saying, " i will blow up this plane", surely Boeing would release this information ASAP. However, if the voice clearly points to a stall system fault, would they be as quick to release their preliminary findings ?
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Old 13th Mar 2019, 07:56
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Originally Posted by greenfields
Well, while not exactly the same, I guess you think they better dump the 777-300ER as well due to the design features needed on that jet??
I don't know, what are those features?
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Old 13th Mar 2019, 08:14
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AoA Sensor

So the AoA Sensor is usually a pretty rugged piece of kit.
What could cause it to fail?
Either the output has an anomaly (electrical/electronic side) or there is a mechanical problem (vane stuck).
What could cause a vane to stick?
Fine sand? Volcanic ash?
Where did this happen?
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Old 13th Mar 2019, 08:23
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Originally Posted by Realbabilu


at least those pilots who saved the previous pk-lqp Dps-cgk lion air won against Mcas accident, without knowing Mcas even existed and stick shaker blaring all along flight.
as a pax, are these pilots that could handle this situation are rare or not ?
if not then Boeing should really re examined their mcas, and aoa parts should be on MEL.
But could whole AOA system tested on ground ?
No not rare. Probably just every day bloke/ttes.
The cheese happened to line up for the crash crew; bad day, sub standard, no sleep, ex wife giving grief, fo thinking about his upcoming tinder date...
sometimes it just all comes together, sadly.
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Old 13th Mar 2019, 08:27
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Originally Posted by KRUSTY 34


One big read button on the yoke that disables ALL automatic functions, including MCAS!

I donít fly the 737, but the regional airliner I have flown for the last 20 years gives total control to the pilot once this button is pushed. Not even the yaw damper is retained. I mean Jesus H Christ! What the hell has happened to simple common sense in design?
I agree, but from the comments on this forum, the aircraft is not capable of flying to normal parameters without MCAS. I.e. the trim adjustment required as AOA increases due to the engine cowling lift. Does that mean it should never have been certified in the first place? Itís not exactly inherently unstable like a fighter, but Boeing have used automation to counteract problems with the design.
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