Ethiopian airliner down in Africa
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Both the FDR and CVR have been found.
https://www.bbc.co.uk/news/world-africa-47521744
https://www.bbc.co.uk/news/world-africa-47521744
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Aerolineas Argentinas pilots concerned and demanding a decision from management. My guess is that if the decsion isn't to ground the Max they'll decline to operate it till matters are clarified
https://www.pagina12.com.ar/180169-p...olineas-argent
https://www.pagina12.com.ar/180169-p...olineas-argent
We most likely know now with 20/20 hindsight, that the AD was not a sufficient reaction to prevent further fatalities.
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Some rough working assumptions (probably overly optimistic):
350 aircraft
In service for 2 years, each aircraft available 340 days/yr, 5 sectors/day.
Total number of departures: approx 1.2m giving a fatal accident rate of 1.67 per million flights.
In comparison using figures up to 2017:
Banderantie - 3.07. (Ouch!)
Concorde - 11.36 (indicative of very low numbers in service and utilisation)
F28 - 1.65
A310 - 1.34
B747 (early models) 1.02
B747 (-400 onwards) - 0.06
B737 (all models) - 0.28
A320 series - 0.11
350 aircraft
In service for 2 years, each aircraft available 340 days/yr, 5 sectors/day.
Total number of departures: approx 1.2m giving a fatal accident rate of 1.67 per million flights.
In comparison using figures up to 2017:
Banderantie - 3.07. (Ouch!)
Concorde - 11.36 (indicative of very low numbers in service and utilisation)
F28 - 1.65
A310 - 1.34
B747 (early models) 1.02
B747 (-400 onwards) - 0.06
B737 (all models) - 0.28
A320 series - 0.11
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Has anyone considered the idea that MCAS was activated appropriately and the crew fought through it even though it was trying to “help” them? ie- they were in a nose high, low airspeed condition. I believe in the Colgan Dash-8 crash, the Captain pulled through the shaker and pusher not believing the aircraft had stalled but (speculation) perhaps believed he was in a tailplalne stall.
They were not in a speed low situation. Their speed was steadily increasing.
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A aircraft with uncommanded trim does not pitch uncontrollably nose down. As the trim motor adds nose down trim up elevator can compensate until the stabilizer overpowers the elevator. At that point the nose will start down. Normally it’s a smooth progression unless the aircraft is on autopilot.
The 737 may have hydraulic power assist to the controls, but please do not think of this as the equivalent of power steering on a car. To counteract the MCAS trim forwards you need to pull with some 60 kg of force, using both control columns, to stop the aircraft nosing into the ground. If you are not prepared for that, or you are busy with something else, you are going down....
A bit like placing the fire handles (and fire warning lamps) out of your field of vision - to confuse you even more.
(The fire handles were originally on the coaming, in front, but Boeing needed somewhere to put the MCP on the classic series. So rather than designing a new flightdeck, they shoved the fire handles on the center panel, where you cannot see them, nor easily access them. The 737-Max still has the standard B-707 and 727 flight deck.)
Silver
Last edited by silverstrata; 11th Mar 2019 at 17:09.
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And the 737 seems to have very few switches in places that aren't the overhead, so the overhead upside-down scheme prevails. But the stab cut out switches are on a place where the normal (up = on) scheme is in place.
@ Indigo A mod too far?
Salute!
For those wondering why MCAS is being discussed. A brief look.
As discussed on another forum and its references, the MCAS was implemented to cope with some aerodynamic "characteristics", as the name suggers:" Maneuvering Charteristics Augmentation System" As others have pointed out, the new engines and their mounting can provide nose up forces at higher than normal AoA. So looks to this old pilot, who has lottsa high AoA experience, the MCAS was supposed to make it harder to command more nose up.
I include a small diagram of pitch coefficient for one plane I flew. At one AoA and higher, the plane "digs in" with neutral controls, and further, it "pitches up" even with forward stick. So it is not surprising Boeing would add something to "help" keep the nose down and not enter that arena where even nose down commands would not be enough. A poster has commented that the 737 stall has plenty of warning, and I doubt it has that one area where nose down stick won't help. Nevertheless, the MCAS looks like it will make it hard to get there. We saw over 100 pounds of back force for JT610 once the trim was way nose down.
You can see the problem.
Gums sends....
Salute!
For those wondering why MCAS is being discussed. A brief look.
As discussed on another forum and its references, the MCAS was implemented to cope with some aerodynamic "characteristics", as the name suggers:" Maneuvering Charteristics Augmentation System" As others have pointed out, the new engines and their mounting can provide nose up forces at higher than normal AoA. So looks to this old pilot, who has lottsa high AoA experience, the MCAS was supposed to make it harder to command more nose up.
I include a small diagram of pitch coefficient for one plane I flew. At one AoA and higher, the plane "digs in" with neutral controls, and further, it "pitches up" even with forward stick. So it is not surprising Boeing would add something to "help" keep the nose down and not enter that arena where even nose down commands would not be enough. A poster has commented that the 737 stall has plenty of warning, and I doubt it has that one area where nose down stick won't help. Nevertheless, the MCAS looks like it will make it hard to get there. We saw over 100 pounds of back force for JT610 once the trim was way nose down.
You can see the problem.
Gums sends....
Last edited by gums; 11th Mar 2019 at 18:19. Reason: typo, et l
Thread Starter
Several more airlines pull the 737 Max after the 2nd crash in Ethiopia.
Royal Air Maroc RAM, and now BA RSA franchise Comair.
This afternoon German press Spiegel say TUI HQ is now considering the grounding of its Boeing 737 Max 8 aircraft . "We are in close contact with Boeing and will evaluate soon the situation with the manufacturer," said Tuifly spokesman Aage Dünhaupt.
But TUI UK are not saying much.
The fleet of the world's largest travel group Tui now includes 15 jets of this type, which are stationed in the United Kingdom and the Benelux countries.
Royal Air Maroc RAM, and now BA RSA franchise Comair.
This afternoon German press Spiegel say TUI HQ is now considering the grounding of its Boeing 737 Max 8 aircraft . "We are in close contact with Boeing and will evaluate soon the situation with the manufacturer," said Tuifly spokesman Aage Dünhaupt.
But TUI UK are not saying much.
The fleet of the world's largest travel group Tui now includes 15 jets of this type, which are stationed in the United Kingdom and the Benelux countries.
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you are busy with something else
I have lost count the number of times that I had to ask the PF to fly the aircraft and I will do any thing required heads down. while at low level. Even in the sim with abnormals people just get sucked into the MCDU while PF. Unreliable airspeed means the PF has to set 80% n1 and fly 10 degrees pitch, that is his only job. If the trim is running against you it should be quite obvious right away as it will be harder and harder to fly 10 degrees pitch. If you are trying to do something else at the same time by the time you look at the pitch again it might be too late.
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Old IT engineer here. Years writing code and more years supervising those who do.I read that after years of outsourcing, Boeing is now reversing that trend and doing more work onshore.
Do we know how much of the design, coding, and testing of the MCAS function was done in-house vs out-sourced? In my experience it’s so hard to manage development when it’s being done off shore, for a variety of reasons, but the same applies to testing. I’d be interested to know of the QA plan, most obviously failure modes, and how it was executed and signed off.
Do we know how much of the design, coding, and testing of the MCAS function was done in-house vs out-sourced? In my experience it’s so hard to manage development when it’s being done off shore, for a variety of reasons, but the same applies to testing. I’d be interested to know of the QA plan, most obviously failure modes, and how it was executed and signed off.
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just had the painfull experience to listen to "aviation expert " on Canadian cbc tv. Where do they find these idiots. CNN is no better. Check out the female ex FAA director. She can't spell plane let alone give any info. These idiots probably get good bucks for this bs
rant over feel a little better.
Operators of the max are experiencing a nightmare as is boeing
rant over feel a little better.
Operators of the max are experiencing a nightmare as is boeing
(pax)Was looking for the unreliable airspeed drill for the 737 and found this
737 airspeed unreliable QRH
Can I ask if the -8 differs ?
737 airspeed unreliable QRH
Can I ask if the -8 differs ?
10 degrees/80% with flap extended, 4 degrees/75% clean. At low altitudes you climb and at high levels descend slightly, but at any altitude the aircraft is under control whilst the PM reads the QRH, asks ATC for a block of altitudes to work in, and then gets the accurate thrust settings and pitch attitudes you need from the performance in flight section of the QRH.
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A couple of thoughts on the recent discussion....
Sorry, a good few places do it the other way around. And therein lies one problem with a global industry.
Perhaps more important is requirement capture before it goes off to the coders (wherever they may be). If assumptions are made at this point - be they about what pilots will know or be able to handle, or the training that they will get to ensure they have sufficient knowledge/competence of a particular system, to pull a couple of examples out of the air - it is vital that they are verified to be correct.
Originally Posted by Vessbot
Yes. The scheme is, on any vertical surface (like the instrument panel, or a wall) up = on, same as any switch in the rest of the world.
Originally Posted by JoeJosh999
Do we know how much of the design, coding, and testing of the MCAS function was done in-house vs out-sourced? In my experience it’s so hard to manage development when it’s being done off shore, for a variety of reasons, but the same applies to testing. I’d be interested to know of the QA plan, most obviously failure modes, and how it was executed and signed off.
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The farmer on whose land it crashed claims it was trailing smoke and debris including clothes.
Per reuters. Can't post urls.
"After Ethiopia crash horror, some nations ground Boeing 737 MAX 8s" posted an hour ago.
Per reuters. Can't post urls.
"After Ethiopia crash horror, some nations ground Boeing 737 MAX 8s" posted an hour ago.
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Requirement capture indeed
Is huge, and again out-source makes everything harder including communications w possible different native language speakers.
It’s that QA failure-mode test I’d like to see. And does anyone w a piloting background get a look before approval? 10-sec on 5-sec off indefinitely unless disabled I’d think would have gotten attention ? I’m naive perhaps.
It’s that QA failure-mode test I’d like to see. And does anyone w a piloting background get a look before approval? 10-sec on 5-sec off indefinitely unless disabled I’d think would have gotten attention ? I’m naive perhaps.
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The farmer on whose land it crashed claims it was trailing smoke and debris including clothes
