Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

Ethiopian airliner down in Africa

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

Ethiopian airliner down in Africa

Old 15th Mar 2019, 13:06
  #1481 (permalink)  
 
Join Date: Mar 2010
Location: Often in Jersey, but mainly in the past.
Age: 74
Posts: 5,115
Originally Posted by Sailvi767 View Post


No, at the density altitude they were at that speed would be well under VNE.
Thank you ... it was just a passing thought.
MPN11 is offline  
Old 15th Mar 2019, 13:13
  #1482 (permalink)  
 
Join Date: Nov 2004
Location: UK
Posts: 403
Quote:For comparison, Volkswagen lost over 60% due to their emission scandal. But this could be, and should be big if it's due to MCAS.
Originally Posted by Icarus2001 View Post
A ridiculous comparison. VW set out to deceive and cheat the emission testing for commercial gain. Boeing added a function to enhance safety when operating at the edge of the envelope, somewhere most crews should and will never be but perhaps a faulty sensor and lack of a second input has caught them out.
Just remember that the crew who flew the affected Lion Air aircraft the day before the fatal managed to land safely. There are trim cut outs, manual trim and electric trim all of which override MCAS inputs.
Quite the opposite; it is a very good comparison - the paralles are very clear to see.

VW had to build a car that could pass the emissions standards. They achieved, through cunning, for commercial gain. And it polluted more than it should have.
Boeing had to build an aircraft that could pass certification. They achieved, through cunning, for commercial gain. Evidence suggests it has killed more people than it should.
pilotmike is offline  
Old 15th Mar 2019, 13:27
  #1483 (permalink)  
 
Join Date: Sep 2016
Location: In the ether
Posts: 15
Originally Posted by Sailvi767 View Post
No, at the density altitude they were at that speed would be well under VNE.
Really? From what I can see Vmo is 340kts on the -800, not sure about the MAX but can't imagine it's different
383kts TAS is 339kts EAS at 8000'
Running Ridges is offline  
Old 15th Mar 2019, 13:27
  #1484 (permalink)  
 
Join Date: Mar 2007
Location: In my head
Posts: 680
Originally Posted by EDML View Post
1. I don‘t think it is possible to survive a flapless T/O at this density altitude and take off mass.
My thoughts too when I also started musing about why a possible first rotation seem to fail (where those first VS reports occurred 2/3rds along the runway, and which DaveReidUK is inclined to put aside pending further clues ) and then they seemed to use so much runway with no height gain, but at the lat/long of Capt Kremin's chosen 207kts GS datapoint (seemingly some 1700ft into the dirt), that dirt beyond the paved areas has already fallen perhaps 150 feet from the runway (according to Google Earth elevations). So it is no Courchevel, and no USS Gerald R. Ford, but the terrain beyond the runway with or without approach light towers, does perhaps offer a little launch ramp type forgiveness.

It is lucky for analysts, that by that point we have no less than 15 ADS-B "airborne" datapoints covering 80% of the available runway and all points without a hint of any spuriousness are located slap bang along the centreline of 07R. Clearly ET302 wasn't airborne at 93kts GS where the first airborne report became available, but that's no real mystery in itself. So thus far I do not question the accuracy of the ADS-B GPS locations reported. It is the altitudes, groundspeeds and vertical speeds which are more questionable, but not overly so. Indeed the altitudes reported along the middle of the runway do seem to reflect moderate undulations found in Google Earth. Whether Google Earth elevations are accurate along the runway is another story.
Originally Posted by EDML View Post
2. Even if they did - after reaching 1000ft and 300kt everything is fine and they could have continued the flight. However, here the disaster started at this point of the flight.
... everything is fine?? Are we sure about that? Where for example do we reckon they actually reached 1000ft above anything until the last few datapoints of the FR24 data?? And on the same score please, DaveReidUK, what point are you calling rotation and what point are you calling 1050ft AAL?
slip and turn is offline  
Old 15th Mar 2019, 13:33
  #1485 (permalink)  
 
Join Date: Dec 2013
Location: US
Age: 61
Posts: 361
Originally Posted by boeingboy737 View Post
If there are any mx tech on here can you tell us if the Stab trim cut out switches are connected to the MCAS system ie will the switches in the cut out position actually stop the MCAS from trimming thanks
They remove all power from the trim motors and completely disable the system.
Sailvi767 is offline  
Old 15th Mar 2019, 13:43
  #1486 (permalink)  
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 9,936
Originally Posted by slip and turn View Post
And on the same score please, DaveReidUK, what point are you calling rotation and what point are you calling 1050ft AAL?
I believe rotation was at approximately the 05:38:47 datapoint (certainly before the next point at 05:38:50).

1050' AAL (8150' ADS-B altitude) was achieved by 05:39:50.

DaveReidUK is online now  
Old 15th Mar 2019, 13:46
  #1487 (permalink)  
 
Join Date: Dec 2013
Location: US
Age: 61
Posts: 361
Originally Posted by Running Ridges View Post
Really? From what I can see Vmo is 340kts on the -800, not sure about the MAX but can't imagine it's different
383kts TAS is 339kts EAS at 8000'
Density altitude would have been above 10,000 feet at airport elevation. 11,000 feet if peak speed was at 1000 AGL
Sailvi767 is offline  
Old 15th Mar 2019, 14:17
  #1488 (permalink)  
 
Join Date: Feb 2015
Location: New Hampshire
Posts: 133
If this is what it appears to be - a problem that will need to be addressed by changing firmware and perhaps hardware, then the MAXs may be grounded for weeks or months.
Flight firmware is not quickly developed and certified.
.Scott is offline  
Old 15th Mar 2019, 14:29
  #1489 (permalink)  
 
Join Date: Oct 2017
Location: Vienna
Posts: 69
Originally Posted by .Scott View Post
If this is what it appears to be - a problem that will need to be addressed by changing firmware and perhaps hardware, then the MAXs may be grounded for weeks or months.
Flight firmware is not quickly developed and certified.
787 was grounded for a month and the solution was a simple cage. I'm 100% sure there is no simple software solution for MCAS. Remember, MCAS is required for (self) certification, so it needs to be there in certain conditions. But it simply can't be there with only two AOA sensors, no matter how you hack it. Whatever you do, it could happen that MCAS does't engage when it should -> hence no certification, or it does when it's deadly.
derjodel is offline  
Old 15th Mar 2019, 14:40
  #1490 (permalink)  
 
Join Date: Mar 2007
Location: In my head
Posts: 680
Originally Posted by DaveReidUK View Post
I believe rotation was at approximately the 05:38:47 datapoint (certainly before the next point at 05:38:50).
OK so it is not until 17 or 20 secs later that you reckon the VS figures begin to read true? And given the airfield elevation 7625' you are deducting how many feet for the QNH1029 correction to convert the 1013hPa 8or 1013.25hPa or 29.92inHg as you will) ADS-B figures to AAL?

1050' AAL (8150' ADS-B altitude) was achieved by 05:39:50.
That implies you may have converted thus: 8150'-7625'+525'=1050'. Are you using 1029-1013.25=15.75 and 15.75hPa x 33.3'/hPa=525'? Because I would use 1029-1013.25=15.75 and 15.75hPa x 27.3'/hPa=430' and conclude that at the 05:39:50 datapoint ET302 was around 950' some odd AAL, but then I may have it all wrong if I am to adjust the rate up from 27.3 to 33.3 because we are well above sea level - if so, I missed it at school

Last edited by slip and turn; 15th Mar 2019 at 15:14. Reason: 950' some odd, not 900' some odd
slip and turn is offline  
Old 15th Mar 2019, 14:41
  #1491 (permalink)  
 
Join Date: Jan 2008
Location: uk
Posts: 732
Originally Posted by Jo90 View Post
Having read (well skimmed) the interim report of the Lion accident particularly the part relating to the previous flight, it occurs to me that following a flight with major instrument discrepancies, continuous stick shaker and multiple uncommanded stab trim movements it might have been appropriate to add something to the tech log entries like "aircraft unfit for revenue flight pending maintenance action".
Would that have prevented the accident?
Maybe, maybe not. Remember, they did log uncommanded trim movements ("STS trimming wrong" - remember they had no knowledge of MCAS even existing) and maintenance action was taken before the last flight - it just didn't find or fix the real problem.

Also, even if it had prevented that accident, it wouldn't prevent one where the first crew that hits the problem cannot cope with it (and ET may well be that).

When trying to pin blame on crews, airlines, maintenance remember that the 737 MAX is a new variant of an existing type (lets restrict to the NG for comparison), same type certificate, same type rating, so similar that the only pilot training is apparently a powerpoint.

NG: ~7000 in service, 16 losses in >20 yrs
MAX: ~ 350 in service, 2 losses in <3 yrs

- same crews
- same training (modulo the powerpoint)
- same airlines
- same maintenance
- same procedures

MAX simply crashes more often, and there's a pattern (shortly after takeoff, flight control problems reported, uncontrolled dive). Even without any knowledge of MCAS you would have to say that there is something wrong with this aircraft and that it's something in the changes from the NG.
infrequentflyer789 is offline  
Old 15th Mar 2019, 14:51
  #1492 (permalink)  
 
Join Date: Jul 2007
Location: Switzerland
Age: 73
Posts: 69
System bugs are caused for three main reasons:
1. Bad Specs
2. Faulty implementatation
3. Incomplete tests and hasty correction of faults.

#1 is by far the worst because it affects #2 and #3 as well and may not be detected during the whole development process.What‘s worse is that in complex developments, this process is cascaded from one system to all of its subsystems.
So here we have an airplane design spec that was most likely not taking into account the aerodynamic behaviour of relocating the engines. I bet the problem was only detected after some test flying of the new airplane. So time runs out, a redesign of the aircraft is now impossible and so a software patch is called for to get better stall protection. The aircraft is not FBW and thus the triple redundancy and voting concept is neither required nor followed. And as all software engineers know, patches sometimes backfire because they have not been designed with the same care as the original system. Ask Bill Gates.

But the patched system is not self-contained, not isolated, it affects and is affected by a lot of other systems and components. If some of these sensors and systems feed wrong air-data, the result is unpredictable probably even for the inventors, but certainly for the poor pilots affected and for the majority of ppruners including me.

Now some of you say „hey that‘s just a little speed bump“, remain cool and switch some breakers and fly away serenely. Thats okay for the Chuck Yeagers and Neil Armstrongs. Those not having been trained as test pilots remain confused and try to fight a plane that does not behave as advertised and tries to kill you and your passengers. They might remember some FAA AD about trim anomalies when they are waiting to pass the pearly gates.

Conclusion: This patch is much worse than the original stability problem. Many aircraft pitch up to a stall if uncorrected after full power is applied, at least mine does. That‘s no issue. It baffles me that a device that can trim a jet fully nose-down without pilot input - caused by some erronous airdata - could ever be conceived and then certified and the facts about this box of Pandora not being passed on to the type-rated pilots and training facilities.
clearedtocross is offline  
Old 15th Mar 2019, 15:31
  #1493 (permalink)  
 
Join Date: Dec 2006
Location: Germany
Posts: 23
Originally Posted by slip and turn View Post
... everything is fine?? Are we sure about that? Where for example do we reckon they actually reached 1000ft above anything until the last few datapoints of the FR24 data?? And on the same score please, DaveReidUK, what point are you calling rotation and what point are you calling 1050ft AAL?
Why not? If you accidently take off w/o flaps the critical moment is when you get out of ground effect. If you manage to accelerate out of that low energy state the aircraft is perfectly flyable. 300kt TAS at 11000ft DA is for sure a safe clean speed. All you might need to do is trim and pull into a normal climb angle.

After a flapless T/O the critical moments would be before reaching 1000ft and not thereafter.
EDML is offline  
Old 15th Mar 2019, 15:39
  #1494 (permalink)  
 
Join Date: Dec 2003
Location: France
Age: 59
Posts: 10
[QUOTE

"So here we have an airplane design spec that was most likely not taking into account the aerodynamic behaviour of relocating the engines. I bet the problem was only detected after some test flying of the new airplane. So time runs out, a redesign of the aircraft is now impossible and so a software patch is called for to get better stall protection."


Clearedtocross, suspect you are spot on with this, and it wouldn't be the first time this has occurred either.

I think Boeing will be lucky to have the aircraft back in the air within 6 months.

MELT is offline  
Old 15th Mar 2019, 15:41
  #1495 (permalink)  
 
Join Date: Mar 2014
Location: WA STATE
Age: 73
Posts: 1
Management documents state that clearly, deviation from accepted quality was permitted to protect schedule. Not the 737 MAX program incidentally, it was the 787.
Not unique to 787- for way too many years after Bill Allen retired, the mantra was ( is ? ) the three most important things in the factory are Schedule- and the other two dont count.
Often its ' load date' ( first load into a specific assembly jig.) Of course other variations - but the basic driving force is the same.

777 was a bit different as both Phil and Alan pushed the ' working together ' mantra in Engineering- and a reasonable amount of it trickled down to shop.
CONSO is offline  
Old 15th Mar 2019, 15:46
  #1496 (permalink)  
 
Join Date: Mar 2014
Location: WA STATE
Age: 73
Posts: 1
So why did they report to the anonymous NASA system and not to their airline and the FAA to have the QAR pulled right away and conserve date?
preservation of job ? uncertain as to problem ? simple write up in log ' check ..... "

CONSO is offline  
Old 15th Mar 2019, 15:55
  #1497 (permalink)  
 
Join Date: Mar 2019
Location: Seattle
Posts: 1
Not trying to defend the MCAS or anything, but wouldn't the last line of defense be the pilots' proficiency to identify the immediate problem and hit the Stab Trim cutout switch if there's a runaway trim in any event? Ample type-specific flight training in this case plays the biggest role in whether one is capable of saving the plane from crashing or not, in spite of not having the "paid" AoA indicator. Granted, the MCAS might've gone rogue on the ET flight, but pilot error seems to be the ultimate cause that sealed the aircraft's fate ..
As evident in the DPS-CGK Lion flight, crew handled the situation pretty well. Landed the plane safely.

Just my 0.02

Last edited by Rolesium; 16th Mar 2019 at 00:11.
Rolesium is offline  
Old 15th Mar 2019, 15:57
  #1498 (permalink)  
 
Join Date: Mar 2006
Location: Vance, Belgium
Age: 57
Posts: 150
Originally Posted by clearedtocross View Post
...
So here we have an airplane design spec that was most likely not taking into account the aerodynamic behaviour of relocating the engines. I bet the problem was only detected after some test flying of the new airplane. So time runs out, a redesign of the aircraft is now impossible and so a software patch is called for to get better stall protection. The aircraft is not FBW and thus the triple redundancy and voting concept is neither required nor followed. And as all software engineers know, patches sometimes backfire because they have not been designed with the same care as the original system. Ask Bill Gates.
What I find hard to understand is why Boeing didn't elect to upgrade the Elevator Feel System for compensating this undesired aerodynamic behaviour and instead created a new MCAS software module in the FCC.
Luc Lion is offline  
Old 15th Mar 2019, 16:04
  #1499 (permalink)  
 
Join Date: Feb 2019
Location: shiny side up
Posts: 221
Article that looked at pilot filings on the MCAS issue...looks like it was common at early DEP, but handled by turning off Autopilot?

The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.

This description is not currently in the 737 Flight Manual Part 2, nor the Boeing FCOM, though it will be added to them soon. This communication highlights that an entire system is not described in our Flight Manual. This system is now the subject of an AD.

I think it is unconscionable that a manufacturer, the FAA, and the airlines would have pilots flying an airplane without adequately training, or even providing available resources and sufficient documentation to understand the highly complex systems that differentiate this aircraft from prior models. The fact that this airplane requires such jury rigging to fly is a red flag. Now we know the systems employed are error prone--even if the pilots aren't sure what those systems are, what redundancies are in place, and failure modes.




https://www.theatlantic.com/notes/2019/03/heres-what-was-on-the-record-about-problems-with-the-737-max/584791/?utm_medium=offsite&utm_source=yahoo&utm_campaign=yahoo-non-hosted&yptr=yahoo
Smythe is offline  
Old 15th Mar 2019, 16:08
  #1500 (permalink)  
 
Join Date: Feb 2019
Location: shiny side up
Posts: 221
I had my first flight on the Max [to] ZZZ1. We found out we were scheduled to fly the aircraft on the way to the airport in the limo. We had a little time [to] review the essentials in the car. Otherwise we would have walked onto the plane cold.

My post flight evaluation is that we lacked the knowledge to operate the aircraft in all weather and aircraft states safely. The instrumentation is completely different - My scan was degraded, slow and labored having had no experience w/ the new ND (Navigation Display) and ADI (Attitude Director Indicator) presentations/format or functions (manipulation between the screens and systems pages were not provided in training materials. If they were, I had no recollection of that material).

We were unable to navigate to systems pages and lacked the knowledge of what systems information was available to us in the different phases of flight. Our weather radar competency was inadequate to safely navigate significant weather on that dark and stormy night. These are just a few issues that were not addressed in our training.

I recommend the following to help crews w/ their introductory flight on the Max:
Email notification the day before the flight (the email should include: Links - Training Video, PSOB and QRG and all relevant updates/FAQ's)
SME (Subject Matter Expert) Observer - the role of the SME is to introduce systems navigation, display management, answer general questions and provide standardized best practices to the next generation aircraft.

Additionally, the SME will collect de-identified data to provide to the training department for analysis and dissemination to the line pilots regarding FAQs and know systems differences as well best practices in fly the new model aircraft.

Synopsis

B737 MAX First Officer reported feeling unprepared for first flight in the MAX, citing inadequate training.


Smythe is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.