Ethiopian airliner down in Africa
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High angle of attack
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The key phrase is "along the lines of" , as apparently Boeing preferred not to admit to the possibility, let alone produce a procedure for it. In the absence of any guidance, what would be the quickest way to inhibit the MCAS system under pressure ? I suspect it would be to reproduce a configuration where it is inactive ?
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Well, I did.
And he is wrong, that is why I responded....
What is your point exactly?
10 degrees/80% with flap extended, 4 degrees/75% clean. At low altitudes you climb and at high levels descend slightly...
At low airspeed you descend and accelerate. At high airspeed you climb and decelerate.
737 experts - please tell us that Boeing didn't do that - or if they did, can anyone explain or justify it?
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The key phrase is "along the lines of" , as apparently Boeing preferred not to admit to the possibility, let alone produce a procedure for it. In the absence of any guidance, what would be the quickest way to inhibit the MCAS system under pressure ? I suspect it would be to reproduce a configuration where it is inactive ?
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Isn't the procedure something more like "if the trim automation is trying to kill us we will switch it off, grab the trim wheel if necessary, then continue to trim manually. This we know from memory?" The only difference is in recognizing the insidious hand of MCAS.
One question though. IIRC the failures in the Lionair incident also messed with the elevator feel system. How would that impact your ability to trim?
One question though. IIRC the failures in the Lionair incident also messed with the elevator feel system. How would that impact your ability to trim?
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No, you follow Boeing procedures. You can read them a few posts above this one.
Switch direction
Trident up on
VC 10 down on
DC9 below windshield up on; above windshield down on.
my first three aircraft.
light switches England down on inside of room.
light switches Ireland down on outside of room.
light switches in Bed and breakfast in Ghent up on outside the room..set a bathrobe alight in the loo after a heavy night out.
only got it wrong once in heavy icing on a dark and dirty night when I switched the engine anti icing off instead of on...and got away with it (switched it back on one at a time with a delay just in case).
VC 10 down on
DC9 below windshield up on; above windshield down on.
my first three aircraft.
light switches England down on inside of room.
light switches Ireland down on outside of room.
light switches in Bed and breakfast in Ghent up on outside the room..set a bathrobe alight in the loo after a heavy night out.
only got it wrong once in heavy icing on a dark and dirty night when I switched the engine anti icing off instead of on...and got away with it (switched it back on one at a time with a delay just in case).
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They are though. Excluding some lights that can be turned on or off from multiple locations, light switches throughout all the houses and apartments I have lived so far (also Western and Eastern Europe) have been down for on.
It's a bit of a silly thing to argue about though. The type that I fly has the basic logic that everything pointing forward means normal ops. "Down" is then usually reserved for AUTO instead of ON, but same difference. I thought the larger issue with switches regarding 737 MAX is that they (the cut-off switches) function in the opposite way from the 737 NG. Not really any point dragging in regular light switches if we are talking about a manufacturers cockpit philosophy.
It's a bit of a silly thing to argue about though. The type that I fly has the basic logic that everything pointing forward means normal ops. "Down" is then usually reserved for AUTO instead of ON, but same difference. I thought the larger issue with switches regarding 737 MAX is that they (the cut-off switches) function in the opposite way from the 737 NG. Not really any point dragging in regular light switches if we are talking about a manufacturers cockpit philosophy.
The reason I'm going on about light switches in rooms (as it turns out, incorrectly) is exploring the pre-existing human factors universal (or not) scheme that that part of aircraft ergonomics is based on. So the up=on scheme is restricted in scope to aircraft, and excludes overhead panels. But to get back to where this branch of the discussion started, the MAX stab cutout switches aren't reversed from previous 737's. Their names are relabeled from "MAIN ELECT" and "AUTOPILOT" to "PRI" and "B/U" but they're all "NORMAL" up and "CUT OUT" down.
http://www.airlinereporter.com/wp-co...light-Deck.jpg
https://s3.amazonaws.com/dsg.files.a...9/Edwilson.jpg
Last edited by Vessbot; 11th Mar 2019 at 22:55.
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MCAS is not and cannot be 100% wrong all the time, so why assume that is the problem if you're thrown into that scenario?
Last edited by positiverate20; 11th Mar 2019 at 23:11.
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All I'm saying is, if in the exact conditions in which you speak, if stick shaker triggered, if either your ASI or AoA indicator in front of you is showing something abnormal, then how can you instantly confirm it's an MCAS error in those circumstances? So, given that scenario, how can you automatically set flap one and reduce power?
MCAS is not and cannot be 100% wrong all the time, so why assume that is the problem if you're thrown into that scenario?
MCAS is not and cannot be 100% wrong all the time, so why assume that is the problem if you're thrown into that scenario?
Gender Faculty Specialist
Trident up on
VC 10 down on
DC9 below windshield up on; above windshield down on.
my first three aircraft.
light switches England down on inside of room.
light switches Ireland down on outside of room.
light switches in Bed and breakfast in Ghent up on outside the room..set a bathrobe alight in the loo after a heavy night out.
only got it wrong once in heavy icing on a dark and dirty night when I switched the engine anti icing off instead of on...and got away with it (switched it back on one at a time with a delay just in case).
VC 10 down on
DC9 below windshield up on; above windshield down on.
my first three aircraft.
light switches England down on inside of room.
light switches Ireland down on outside of room.
light switches in Bed and breakfast in Ghent up on outside the room..set a bathrobe alight in the loo after a heavy night out.
only got it wrong once in heavy icing on a dark and dirty night when I switched the engine anti icing off instead of on...and got away with it (switched it back on one at a time with a delay just in case).
I've flown ex Lufthansa 737s one day and ex Ansett the next where switches operated in the opposite sense. Didn't take much getting used to.
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In the UK:
While the universal standard for light and power/socket switches is down for on, you can easily get three pole bathroom "run on" fan isolator switches in both configurations. Ie those which have up as off and those which have down as off.
Additionally the standard for items in consumer units (house fuse boards) being circuit breakers/MCBs, Rcbo's, and RCD units is up for on.
While the universal standard for light and power/socket switches is down for on, you can easily get three pole bathroom "run on" fan isolator switches in both configurations. Ie those which have up as off and those which have down as off.
Additionally the standard for items in consumer units (house fuse boards) being circuit breakers/MCBs, Rcbo's, and RCD units is up for on.
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Its a fair point. And a clear AOA indication will grant further cognition of the condition. However a trim system that repeatedly trys to shove the nose in to the deck despite the crews efforts to trim back to level flight and cumulatively builds up forces that quickly require two sets of hands pulling on the control column might be the clue that MCAS is trying to kill you ?
Cast my vote with the "follow the procedure" crowd.
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To be clear, which switches are you talking about? The stab cutouts? The overhead?
