Ethiopian 737 MAX 8 crash
03-18-2019, 03:28 PM
#311
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Originally Posted by Peacock
The MAX will most likely be “fixed” with a software update and zero airframe modification.
But hey maybe you’re right and they’ll test and then retrofit new wings, landing gear, tail, and cockpit onto hundreds of planes to make “a lighter weight 757”.
But hey maybe you’re right and they’ll test and then retrofit new wings, landing gear, tail, and cockpit onto hundreds of planes to make “a lighter weight 757”.
03-18-2019, 03:41 PM
#312
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Originally Posted by F4E Mx
Or just reopen the 757 line. The odds of Boeing ever delivering 5,000 of the MAX airplanes, or whatever the back-order number is, are not high. With the 757 you have adequate landing gear for the airframe, no preflattened nacelles, and no Rube Goldberg nose-down system wired in to the stabilizer trim mechanism. They won't do it of course. Makes too much sense. Boeing could call it the 757neo
Without a "NEO" update, it would fail miserably in fuel burn compared to the various A321NEO versions. That would take even more years and $.
Nobody would buy it, they'd just get on the airbus waiting list for NEOs.
03-18-2019, 03:47 PM
#313
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Originally Posted by Peacock
The MAX will most likely be “fixed” with a software update and zero airframe modification.
Agreed.
Originally Posted by UAL T38 Phlyer
My guess:
1. Comparator logic, so that MCAS uses data from BOTH AoA vanes. In the event of disagreement, it would either be inhibited, or an alert. Possibly a disable-switch added.
2. Mandatory sim-training where the MCAS runs away.
3. I think it will happen in phases. AoA mod will happen quickly...I believe it’s there, just needs to be modded in the software.
A disable switch would take a year to get delivered airplanes modded. New would include it.
Sim training: they’ll give them six months to train everyone.
Flying again by May 15.
Just a guess.
1. Comparator logic, so that MCAS uses data from BOTH AoA vanes. In the event of disagreement, it would either be inhibited, or an alert. Possibly a disable-switch added.
2. Mandatory sim-training where the MCAS runs away.
3. I think it will happen in phases. AoA mod will happen quickly...I believe it’s there, just needs to be modded in the software.
A disable switch would take a year to get delivered airplanes modded. New would include it.
Sim training: they’ll give them six months to train everyone.
Flying again by May 15.
Just a guess.
1. Yes, something like that. I assume all sensors feed to a data bus of some sort? As I understand it, each of the 2 FCCs gets data from a single AOA sensor, not both. Wondering if the fix is for the active FCC to read from both AOAs or for the active FCC interact with the non-active FCC to compare AOA inputs?
2. Already done, but I know what you mean...
3. I would assume it could be done fairly quickly, assuming a central data bus or an easy interconnect between data busses which would make the fix purely a programming fix? That may be the fix that Boeing was about to push?
I assume a disable switch would just be a logic input to tell the active FCC to quit the MCAS routine?
03-18-2019, 04:25 PM
#314
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Posts: 659
Originally Posted by F4E Mx
Or just reopen the 757 line. The odds of Boeing ever delivering 5,000 of the MAX airplanes, or whatever the back-order number is, are not high. With the 757 you have adequate landing gear for the airframe, no preflattened nacelles, and no Rube Goldberg nose-down system wired in to the stabilizer trim mechanism. They won't do it of course. Makes too much sense. Boeing could call it the 757neo
03-18-2019, 05:52 PM
#315
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Posts: 936
Originally Posted by F4E Mx
Or just reopen the 757 line. The odds of Boeing ever delivering 5,000 of the MAX airplanes, or whatever the back-order number is, are not high. With the 757 you have adequate landing gear for the airframe, no preflattened nacelles, and no Rube Goldberg nose-down system wired in to the stabilizer trim mechanism. They won't do it of course. Makes too much sense. Boeing could call it the 757neo
03-18-2019, 09:58 PM
#317
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Posts: 6,457
Originally Posted by UAL T38 Phlyer
My guess:
1. Comparator logic, so that MCAS uses data from BOTH AoA vanes. In the event of disagreement, it would either be inhibited, or an alert. Possibly a disable-switch added.
1. Comparator logic, so that MCAS uses data from BOTH AoA vanes. In the event of disagreement, it would either be inhibited, or an alert. Possibly a disable-switch added.
Would FAA really approve a single AoA failure as "extremely improbable" (as required by P25).
03-19-2019, 03:40 AM
#318
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Posts: 936
Originally Posted by dera
Can they do that, given that the plane will not pass Part 25 standards without MCAS?
Would FAA really approve a single AoA failure as "extremely improbable" (as required by P25).
Would FAA really approve a single AoA failure as "extremely improbable" (as required by P25).
03-19-2019, 04:04 AM
#319
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Posts: 281
What happens with the system when the flap lockout mechanism doesn't work and the system actuates at lift-off with take-off flaps extended or on approach with the flaps extended? Those are high angle-of-attack situations.
What happens if the system doesn't work at all when the aircraft approaches a stall, especially at a high altitude?
Those obviously are not issues with other models of the 737 that don't have the system. There was an aircraft designer who famously said: "The parts you leave out never fail".
What happens if the system doesn't work at all when the aircraft approaches a stall, especially at a high altitude?
Those obviously are not issues with other models of the 737 that don't have the system. There was an aircraft designer who famously said: "The parts you leave out never fail".
03-19-2019, 04:13 AM
#320
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Posts: 936
Originally Posted by F4E Mx
What happens with the system when the flap lockout mechanism doesn't work and the system actuates at lift-off with take-off flaps extended or on approach with the flaps extended? Those are high angle-of-attack situations.
What happens if the system doesn't work at all when the aircraft approaches a stall, especially at a high altitude?
Those obviously are not issues with other models of the 737 that don't have the system. There was an aircraft designer who famously said: "The parts you leave out never fail".
What happens if the system doesn't work at all when the aircraft approaches a stall, especially at a high altitude?
Those obviously are not issues with other models of the 737 that don't have the system. There was an aircraft designer who famously said: "The parts you leave out never fail".
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