B may have pushed the 737 design a step too far

Post #427,879 by scoenye 3/12/19 8:08:43 PM 3/12/19 8:08:43 PM Reply	B may have pushed the 737 design a step too far The new motors are much larger than the originals and do not fit under the wing, even with an extra 8" of lift in the front undercarriage. Boeing had to move the things forward and up. That in turn has made a previously stable airframe unstable at high angles of attack because the new engine configuration wants to keep lifting the nose. Enter MCAS in an attempt to keep the engines from pulling the plane over the stall threshold. One thing that may not be apparent to all is that the MCAS cutout does not restore things to normal as would shutting down other software controls. The trim change must be undone manually. (And American Airlines apparently told its crews to turn it off after the Lion Air crash. [There's no off button. Read that as "pull the breaker"])
Post #427,893 by mmoffitt 3/13/19 9:00:19 AM 3/13/19 9:00:19 AM Reply	No "off button" but there are "Cut-Out Switches". And they aren't hidden. Normal electric trim control on the yoke can stop the MCAS-driven stabilizer movement, however MCAS will activate again within five seconds after the switches are released if the angle of attack is still sensed too high. Pilots can deactivate MCAS and automated control of the stabilizer trim with the cutout switches and hand-crak the trim wheels on each side of the throttle quadrant for manual trim. More here: https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/ If it turns out that this second CFIT is related to MCAS, what do you want to bet that neither captains nor first officers hit those switches? bcnu, Mikem It's mourning in America again.
Post #427,897 by Ashton 3/13/19 2:47:53 PM 3/13/19 3:00:59 PM Reply	"Pilots complained about the 737 Max in a federal database" CNN. Pilot: Flight Manual on 737 MAX "is inadequate and almost criminally insufficient" Other pilot complaints from the federal database include a report saying it is "unconscionable" that Boeing, the US aviation regulatory agency (the Federal Aviation Administration) and the unnamed airline would have pilots flying without adequate training or sufficient documentation. The same entry also charges that the flight manual "is inadequate and almost criminally insufficient." ..can't add much to that. Prediction: the phrase, "PILOTS DON'T NEED TO KNOW _______" (about whatever predicate) will never again be uttered by anyone in the $$$$Industry, including the bloody-FAA. Guess also: Perhaps the flight Manual departments everywhere will revise their entire M.O. Perhaps writing-in-RED: such hints as EXACTLY how you COMPLETELY-DISABLE a strongly or weakly SUSPECTED item. And no more "six seconds after you kill after a first porpoise": IT COMES BACK TO LIFE! aka "For want of a nail the horse-shoe came off; for want of a horse ...WW-III began" to-coin-a-phrase. :-/ Edited by Ashton March 13, 2019, 03:00:59 PM EDT Expand All History
Post #427,900 by mmoffitt 3/13/19 4:37:44 PM 3/13/19 4:37:44 PM Reply	From that very article. *Emphasis Mine.* In another complaint, a first officer reported that the aircraft pitched nose down after the autopilot was engaged during departure. *The autopilot was then disconnected and flight continued to its destination, according to the database.* Is the system flawed? Obviously. Are there mitigating steps a pilot can perform? Obviously. I'm as disappointed in Boeing as anyone, but the fact remains that it was not exclusively Boeing's fault those aircraft ended up in the ground. I had to look it up and it turns out that for many airlines the autopilot can be turned on as low as 400 ft AGL on take-off. I asked a couple of retired ATP's about that and they both said they hand flew to about 10,000 ft or so before engaging the AP on take-off. I'd bet that isn't common these days. bcnu, Mikem It's mourning in America again.
Post #427,909 by rcareaga 3/14/19 8:21:49 PM 3/14/19 8:21:49 PM Reply	from the WaPo today Pilots were abuzz over publicly available radar data that showed the aircraft had accelerated far beyond what is considered standard practice, for reasons that remain unclear. “The thing that is most abnormal is the speed,” said John Cox, an aviation safety consultant and former 737 pilot. “The speed is very high,” said Mr. Cox, a former executive air safety chairman of the Air Line Pilots Association in the United States. “The question is why. The plane accelerates far faster than it should.” I suppose we can’t rule out “pilot error” when it comes to the crew’s response, but it appears to me that a Boeing product ought not to require the pilots to correct behavior like this a few minutes into the flight. cordially,
Post #427,940 by mmoffitt 3/18/19 8:32:48 AM 3/18/19 8:32:48 AM Reply	Somewhat agree. While I agree "a Boeing product ought not to require the pilots to correct behavior like this", I also hold that it is more important that "any product allow for pilots to correct behavior like this." This is the heart of my rationale for never looking at airlines when booking flights, but only at aircraft and only fly an Airbus product if (1) it is an emergency and (2) there is no other option available. bcnu, Mikem It's mourning in America again.
Post #427,902 by scoenye 3/13/19 6:58:19 PM 3/13/19 6:58:19 PM Reply	Thanks. Misread that first time around. I found that in the wake of the Lion Air crash, but my brain somehow glued the cutout and the 5 sec reactivation together. Not good for reasoned arguments :-/
Post #427,899 by Ashton 3/13/19 3:43:42 PM 3/13/19 3:53:17 PM Reply	'Twas my first wonderment also; IF you've altered ALL the C.G. relationships to such a degree that: you even have to glue-together an MCAS kluge ... [shades of the "flies like a brick"==completely un-Pilotable IF the many feedback systems are cut off: in most War-planes du jour] THEN: (the difficulties always of, 'proving a negative') until you do all the white-knuckle aerobatics tests--so highly unlikely re any gigantic Flying Auditorium-- [save for that period of Inverted-flight for n-minutes : in that Crash (not a MAX IIRC) near LAX wherein they indeed kept the sucker almost stably in-the-air until the same uncontrollability sent it augering-in to the ocean, straight down] THEN: just HOW 'flyable' IS? this NEW-design amidst the vicissitudes of weather, engine-failure on one side [new "virtual-CG physics" re that lopsided-power thing, added to physical CG matters] ..and like that. I mean, when the static-CG MEANS that the plane will always want to fly Nose-^UP^ unless a bloody handful of sensors and software/assumed Perfect ... are always on-line? Acceptable in a Military plane? Yess, one supposes. In an aircraft with hundreds aboard? 'Course then there's Airbus, but I digress. {Don't ask the dis-U.S. Supreme Court to make This call, eh? :-/ } Worst case: what IF this glue-on-some bigger/heavier engines wherever we can make them fit has created a Very-expensive Franken-Liner? (which brings us back to the FACT): that this 'NEW Design" was permitted by FAA et alia: to SKIP the mandatory Flight Simulator Time/per every Pilot: and go into production as a mere ".."made a few improvements", cha. cha. cha. I smell BIG-$$$ payed-out and Boeing public spanking--and a reduced Trust of the entire U.S. plane-certifying process--at least in the minds of the semi-ept ..and maybe even the proles. Edited by Ashton March 13, 2019, 03:53:17 PM EDT Expand All History
Post #427,901 by scoenye 3/13/19 6:23:12 PM 3/13/19 6:23:12 PM Reply	It still handles fine in level flight The nacelles are designed so they do not generate lift at cruising attitude. The problem shows up at higher angles of attack, as at take-off, because then the nacelles do generate lift and the moment acts to push the nose even higher.

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