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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 2nd Apr 2019, 15:35
  #2901 (permalink)  
 
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Originally Posted by Cows getting bigger
I'll try and keep this simple. $120m aircraft has a single point of failure (AOA vane) that will subsequently cause HAL to become suicidal.
#1 radio altimeter failure can have the same effect.

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Old 2nd Apr 2019, 15:42
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Originally Posted by Ian W
Well Biggles may not understand what to do - but Ginger has read about the problems and learned that a UAS with all the bells and whistles in the cockpit on takeoff was one of the first indications of a problem that could lead to a crash and that either not fully raising flap or switching off the Stab Trim would prevent the issue. So he turned down Biggles' offer of the weight training courses and went instead for switching off Stab Trim as first action on a UAS or if it was immediately on take off just leave some flap down as this was what was in the ACs/ADs that Biggles was using as a coffee mat.
When Ginger read (if she did) the updated manual she would have seen, from the emergency AD.
g) Revision of Airplane Flight Manual (AFM): Certificate Limitations Within 3 days after receipt of this AD, revise the Certificate Limitations chapter of the applicable AFM to include the information in figure 1 to paragraph (g) of this AD. Figure 1 to paragraph (g) of this AD – Certificate Limitations Required by AD 2018-23-51

Runaway Stabilizer
In the event of an uncommanded horizontal stabilizer trim movement, combined with any of the following potential effects or indications resulting from an erroneous Angle of Attack (AOA) input, the flight crew must comply with the Runaway Stabilizer procedure in the Operating Procedures chapter of this manual:

• Continuous or intermittent stick shaker on the affected side only.
• Minimum speed bar (red and black) on the affected side only.
• Increasing nose down control forces.
• IAS DISAGREE alert. • ALT DISAGREE alert.
• AOA DISAGREE alert (if the option is installed).
• FEEL DIFF PRESS light.
• Autopilot may disengage. • Inability to engage autopilot
"a UAS with all the bells and whistles in the cockpit on takeoff was one of the first indications of.." does not jump out at the reader.
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Old 2nd Apr 2019, 15:50
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Originally Posted by bill fly
Has anyone knowledge of stab motor overheat scenarios or motor specs on the Max?
If the stab trim is trimmed continuously - down, then up, then down - etc. for minutes on end, is it possible that the motors can eventually overheat and quit?
...
To test the control cable and chain adjustment you have among others "Operate the stabilizer system through 5 full cycles."
So I do not see an overheat problem...
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Old 2nd Apr 2019, 15:51
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Someone must have seen this coming. A massive increase in the demand for airplanes, a critical shortage of experienced pilots and technology available to completely automate every aspect of flying an airliner. These two accidents are a perfect example of a problem that is only going to get worse. You can’t make better pilots by putting them in airplanes that fly themselves until the day they don’t, then expecting them to fly it out of the fire. The days of good hands and feet flying are never coming back, and this is not news to those who make the software. The sooner we give up and turn it all over to them the better. You can rest assured they are ready for it, even if the public and the pilots are not. That said, if it was me getting kicked out of the loop they would have to pry my cold dead hands off the controls.

Last edited by ferry pilot; 2nd Apr 2019 at 16:58.
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Old 2nd Apr 2019, 19:58
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Salute Ferry !!
I love it.

Although I flew very sophisticated aerospace vehicles, I am not quite ready to let HAL run everything at this time. And you are correct about not providing the human crewmembers with realistic training and practice for that one day they may have to actually perform their 'Chuck Yeager" routine. The "children of the magenta line" still live, and there's more of them every year.
CASE IN POINT:
The Lion 610 and previous flight's MCAS problem would not have been handled successfully by HAL, especially if the same sfwe shop did the design and code. At the time of Lion 610, the problem facing the plane was not the basic "runaway trim" that most of us think about. Then there;s the stall warning! HAL would likely have commanded some nose down, huh? Did HAL know altitude above the terrain or note the rising terrain ahead? Did the sfwe folks think that MCAS would activate at takeoff speed, and a few hundred feet and not at the other end of the envelope doing a banked turn at 20,000 feet? Would HAL have reduced power at 700 feet with stall warning shaking and been aware that getting too fast would reduce elevator effectiveness due to "blow up" with AND trim being commanded?

The single point of failure, the AoA doofer, that everyone points out was only the first event in the sequence that eventually resulted in loss of control. Just like almost all crashes. Few are the result of one thing going tango uniform. And that is where HAL has trouble, but the carbon-based lifeforrms can connect things that HAL's father had not thot of, and then do something not "programmed". You know, turn off both electric stab switches before treating the stall warning and not experiencing continuous trim in one direction.

Gums opines...
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Old 2nd Apr 2019, 20:17
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Originally Posted by Ian W
My highlight.
Sim training in some places seems from comments here to be very samey. So the expectations of the people writing the NNC and the trained reactions of the crews have diverged significantly.

The designers obviously felt that the worse thing to happen would be a crew switching stab trim off in the highly unlikely event that the AoA failed (they probably checked failure rates in NGs). Seems that for some crews switching stab trim off is very unlikely even when the trim is motoring way down and making things uncomfortably heavy and for some reason the AoA vanes have a lot higher failure rate in the Max.
Yes but I find this response unconscionable.

I think I would have found it.

You think you would have found it.

Two professional crews flew it into the ground within a few months very early in the adoption cycle of this aircraft.

Training and experience didn't change.

What changed was the introduction of MCAS.

I can't find that the fault of the aircrew and don't see how anyone else can.
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Old 2nd Apr 2019, 20:26
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Originally Posted by Turbine70
Yes but I find this response unconscionable.

I think I would have found it.

You think you would have found it.

Two professional crews flew it into the ground within a few months very early in the adoption cycle of this aircraft.

Training and experience didn't suddenly change.

What changed was the introduction of MCAS.

I can't find that the fault of the aircrew and don't see how anyone else can.
See Ferry Pilot #2945
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Old 2nd Apr 2019, 20:33
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Originally Posted by IFixPlanes
To test the control cable and chain adjustment you have among others "Operate the stabilizer system through 5 full cycles."
So I do not see an overheat problem...
Thanks Ifix,
That is on ground, with no aerodynamic load I guess?
The two accidents happened in warm places...
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Old 2nd Apr 2019, 20:46
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Originally Posted by gums
Salute Ferry !!
I love it.

Although I flew very sophisticated aerospace vehicles, I am not quite ready to let HAL run everything at this time. And you are correct about not providing the human crewmembers with realistic training and practice for that one day they may have to actually perform their 'Chuck Yeager" routine. The "children of the magenta line" still live, and there's more of them every year.
CASE IN POINT:
The Lion 610 and previous flight's MCAS problem would not have been handled successfully by HAL, especially if the same sfwe shop did the design and code. At the time of Lion 610, the problem facing the plane was not the basic "runaway trim" that most of us think about. Then there;s the stall warning! HAL would likely have commanded some nose down, huh? Did HAL know altitude above the terrain or note the rising terrain ahead? Did the sfwe folks think that MCAS would activate at takeoff speed, and a few hundred feet and not at the other end of the envelope doing a banked turn at 20,000 feet? Would HAL have reduced power at 700 feet with stall warning shaking and been aware that getting too fast would reduce elevator effectiveness due to "blow up" with AND trim being commanded?

The single point of failure, the AoA doofer, that everyone points out was only the first event in the sequence that eventually resulted in loss of control. Just like almost all crashes. Few are the result of one thing going tango uniform. And that is where HAL has trouble, but the carbon-based lifeforrms can connect things that HAL's father had not thot of, and then do something not "programmed". You know, turn off both electric stab switches before treating the stall warning and not experiencing continuous trim in one direction.

Gums opines...
/sarcasm/ Ahhh but you miss the magic of automation: Hal would -never- get itself into a incipient stall in the first place./sarcasm/

Gums: thanks very much for your 'real world' perspective on all of this

It is true that MCAS is only active when autopilot is disabled, the autotpilot does not get confused by the non-linear change in control force.
Also true HAL could handle all the available sensors without sensory overload so in this case quite possibly the AOA disagree would have just been logged and flight continued.
Although there would have been more than 2 if HAL was in full charge, I hope

Very long term I can see that a fully automatic system might -overall- be safer but anything that has to rely on 'human exception handling' is a far from there.

If anything this whole mess point to a major issue when different philosophies are intermingled, 9 parts "the pilot is in control", one part "except when we don't think so".
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Old 2nd Apr 2019, 21:17
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Originally Posted by Ian W
See Ferry Pilot #2945
Actually I agree with Ferry Pilot and concur that the inevitable and unstoppable answer to imperfect automation is improved automation.

That said he is discussing a long term trend and I am discussing a step change.

That yesterday's crews can deal with faults in today's automation is irrelevant or at least of very limited utility.

It was unreasonable to expect today's crews to deal with this automation now.

The conclusion is that this automation should not have been introduced, and Boeing are recognising this by fixing it so that it is safe for today's pilots.

Last edited by pilot9250; 2nd Apr 2019 at 22:57.
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Old 2nd Apr 2019, 22:57
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Whistleblowers claim aviation inspectors who evaluated Boeing 737 MAX were poorly trained

April 2, 2019 4:34 pm

The U.S. Senate Commerce Committee is investigating claims by a number of whistleblowers that aviation safety inspectors, including some who worked to evaluate the now-grounded Boeing 737 MAX, were not properly trained or certified, the committee chairman said on Tuesday.

More than 300 Boeing 737 MAX jets have been grounded worldwide after two crashes -- in Indonesia in October and in Ethiopia last month -- killed nearly 350 people.

Senator Roger Wicker, a Republican, said in a letter to the Federal Aviation Administration that the FAA may have been notified about the training and certification concerns as early as August 2018 -- before the Indonesia crash -- citing information from the whistleblowers and documents.

The letter did not disclose if the whistleblowers worked for Boeing, the FAA or another entity. The FAA has come under criticism for delegating some of its certification responsibilities to Boeing and other manufacturers.

In his letter, Wicker asked acting FAA administrator Daniel Elwell to provide answers to detailed questions by April 16...

...Wicker's letter said the whistleblowers alleged that safety inspectors without proper safety training could have been participants on the Flight Standardization Board that evaluated the 737 MAX 8 to "determine the requirements for pilot type ratings, to develop minimum training recommendations, and to ensure initial flightcrew member competency."...


Source:
- https://globalnews.ca/news/5123264/b...histleblowers/
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Old 2nd Apr 2019, 23:05
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The days of good hands and feet flying are never coming back, and this is not news to those who make the software.
I don’t want to agree with you. Hopefully you’re incorrect.
At the moment the regulator mandates that I get 8 hours of simulator time p/a. In reality it’s more like 16 because the pilot I am teamed up with also needs 8 hours. We complete this over two checks held six months apart. If the regulator mandated that I need 12 hours, and the extra four hours had to be sans automation and both high level and circuit work, the difference in my handling skills and confidence as a pilot would be significant. The cost would easily be passed onto the flying public and would effect all operators equally.
With all the cosy relationships between Airlines and regulators and manufactureres globally I won’t hold my breath but it would go a long way to making our Industry safer for very little cost.
This is one situation that would benefit from some autocratic leadership and hang the corporate consequences......anyone know a leader like that?
Edited to add; A ‘bad outcome’ from the Max saga would be that Boeing tinker with their software and manage their corporate relationships to get the aircraft flying again.
A ‘good outcome’ to the saga would be if pilots around the world became more competent through mandated automation-free sim time that is in addition to the current requirements.

Last edited by 73qanda; 2nd Apr 2019 at 23:17.
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Old 2nd Apr 2019, 23:15
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Gums,

HAL just eats the data coming down the wire and keeps going. Human can notice things are going pearshaped, point Mark I eyeball out nearest viewport and evaluate real-world situation, hopefully even recover..

On the other hand, sadly, it's harder to postmortem diagnose and later avoid human error than mechanical error, even when honest efforts at discovery are made.

Edmund



Originally Posted by gums
Salute Ferry !!
I love it.

Although I flew very sophisticated aerospace vehicles, I am not quite ready to let HAL run everything at this time. And you are correct about not providing the human crewmembers with realistic training and practice for that one day they may have to actually perform their 'Chuck Yeager" routine. The "children of the magenta line" still live, and there's more of them every year.
CASE IN POINT:
The Lion 610 and previous flight's MCAS problem would not have been handled successfully by HAL, especially if the same sfwe shop did the design and code. At the time of Lion 610, the problem facing the plane was not the basic "runaway trim" that most of us think about. Then there;s the stall warning! HAL would likely have commanded some nose down, huh? Did HAL know altitude above the terrain or note the rising terrain ahead? Did the sfwe folks think that MCAS would activate at takeoff speed, and a few hundred feet and not at the other end of the envelope doing a banked turn at 20,000 feet? Would HAL have reduced power at 700 feet with stall warning shaking and been aware that getting too fast would reduce elevator effectiveness due to "blow up" with AND trim being commanded?

The single point of failure, the AoA doofer, that everyone points out was only the first event in the sequence that eventually resulted in loss of control. Just like almost all crashes. Few are the result of one thing going tango uniform. And that is where HAL has trouble, but the carbon-based lifeforrms can connect things that HAL's father had not thot of, and then do something not "programmed". You know, turn off both electric stab switches before treating the stall warning and not experiencing continuous trim in one direction.

Gums opines...
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Old 2nd Apr 2019, 23:33
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For years military aviation has been going down the path, where the aircraft needs a certain level of automation just to be able to fly. It seems that that philosophy is creeping into commercial aviation in the never ending quest for cost reduction & the 737 MAX & itís MCAS is evidence of that trend. The thing the designers seem to have forgotten or ignored is that in an airliner we canít eject when the automation fails or does what is unintended.
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Old 3rd Apr 2019, 00:32
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If Ethiopian Airlines experienced controllability problems very shortly after takeoff, at 400-500 ft AGL, is it likely that the plane was in clean configuration already?
And if not, what does that say about the issues the pilots were facing ?
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Old 3rd Apr 2019, 01:08
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Hand fly the darn thing

Today I had the opportunity to talk with a line pilot from a major US carrier that has both 737NGs and MAX 9ís in their fleet, and we chatted about both Lion and Ethiopian incidents. He routinely flys 737NGs and had only flown the MAX on one leg to date, but had nothing other than good things to say about it.

Thatís not the point of this post - what is, was his absolute certainty that ANY pilot flying the MAX post-Lion crash should have known in a heartbeat the symptoms of a misbehaving AOA sensor and how to disable MCAS. He was unequivocal that this would be a non-event.

Additionally he noted that he routinely hand-flys the aircraft on departure to 10,000 or 18,000 feet (route dependent) and would only then switch on the AP. Equally, on approach he would switch off the automatics around 6,000 feet and hand-fly the aircraft. This is encouraged by his airline. This seems rather different than many these days.

His point was any time the airplane isnít doing something he expected - turn off all the automatics including electric trim and figure out what was going on.

I asked whether he felt he would have turned off the trim BEFORE he knew about MCAS, and he was adamant that any repeated trim as experienced by Lion Air would have had the electric trim disabled no more than the second iteration. Itís simply not the same trim action as that which occurs with the STS, and would have turned off.

Of course this anecdotal and simply one pilotís input, but take it for what it is. This pilot said he would fly a MAX tomorrow without concern.

- GY
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Old 3rd Apr 2019, 01:10
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Originally Posted by Oakape
For years military aviation has been going down the path, where the aircraft needs a certain level of automation just to be able to fly. It seems that that philosophy is creeping into commercial aviation in the never ending quest for cost reduction & the 737 MAX & itís MCAS is evidence of that trend. The thing the designers seem to have forgotten or ignored is that in an airliner we canít eject when the automation fails or does what is unintended.
The real problem with 737 MAX is the overlaying of FBW features (some initially hidden) on an updated legacy design to make it mimic an earlier version to keep it 'in family'.

A 737 MAX airframe made fully FBW Airbus sidestick style would be a safe airplane with no need for kludges such as MCAS or STS.
From what I have read even 'raw mode' would be fine although a bit touchy in some cases.

Of course then it would no longer be a 737 so that would be a non-starter.



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Old 3rd Apr 2019, 01:24
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Originally Posted by Garage Years
Additionally he noted that he routinely hand-flys the aircraft on departure to 10,000 or 18,000 feet (route dependent) and would only then switch on the AP. Equally, on approach he would switch off the automatics around 6,000 feet and hand-fly the aircraft. This is encouraged by his airline. This seems rather different than many these days.
I have no doubt that the automation policies of some outfits reduces the ability of pilots to detect and counter abnormal handling characteristics when they are (forced to) hand flying. The autopilot is an aid, not a crutch.
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Old 3rd Apr 2019, 02:00
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The problem is the autopilot is a crutch to perhaps 85% of airline pilots in Asia, Europe, India and the Middle East. As is the flight director, too. The FOQA computer transmits all handling back to the engineering base and flight crew heads roll if it detects FD turned off, or AP not engaged. It depends on the operator of course but the knowledge that FOQA is monitoring so many parameters is enough to discourage flight crews from keeping their hand in during line flying.
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Old 3rd Apr 2019, 02:15
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Sheppey, I have no doubt what you say is true, even though it is not right.
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