Southwest uses the same new Boeing plane in Indonesia crash
Nov 17, 2018, 12:11 pm
#91
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FAA evaluates a potential design flaw on Boeing’s 737 MAX after Lion Air crash
Any pilot’s natural reaction when a plane’s nose begins to tilt down uncommanded is to pull back on the yoke and raise the nose. In normal flight mode, that would work, because pulling back on the yoke triggers breakout switches that stop any automatic tail movement tending to move the nose of the plane down.
But with the MCAS activated, said Fehrm, those breakout switches wouldn’t work. MCAS assumes the yoke is already aggressively pulled back and won’t allow further pullback to counter its action, which is to hold the nose down.
Fehrm’s analysis is confirmed in the instructions Boeing sent to pilots last weekend. The bulletin sent to American Airlines pilots emphasizes that pulling back the control column will not stop the action.
Fehrm said that the Lion Air pilots would have trained on 737 simulators and would have learned over many years of experience that pulling back on the yoke stops any automatic tail maneuvers pushing the nose down.
“It fits in your feel memory,” said Fehrm of this physical way of learning. But on the Lion Air flight, if MCAS was active because of a faulty sensor, the pilots would have pulled back and found the downward nose movement didn’t stop.
Fehrm is convinced this led to confusion in the cockpit that contributed to the loss of control. There is a standard procedure to shut off any automatic pitch control, but somehow the pilots didn’t recognize that’s what was happening.
“MCAS had the wrong information and they reacted to that.,” he said. “MCAS is to blame.”
However, he cautions that there’s not enough information yet to know that the single AOA sensor failure triggered everything that happened, and that the entire sequence of events that led to the disaster won’t be clear until the investigation is completed. “It may not be as simple as a single sensor,” he said.
But with the MCAS activated, said Fehrm, those breakout switches wouldn’t work. MCAS assumes the yoke is already aggressively pulled back and won’t allow further pullback to counter its action, which is to hold the nose down.
Fehrm’s analysis is confirmed in the instructions Boeing sent to pilots last weekend. The bulletin sent to American Airlines pilots emphasizes that pulling back the control column will not stop the action.
Fehrm said that the Lion Air pilots would have trained on 737 simulators and would have learned over many years of experience that pulling back on the yoke stops any automatic tail maneuvers pushing the nose down.
“It fits in your feel memory,” said Fehrm of this physical way of learning. But on the Lion Air flight, if MCAS was active because of a faulty sensor, the pilots would have pulled back and found the downward nose movement didn’t stop.
Fehrm is convinced this led to confusion in the cockpit that contributed to the loss of control. There is a standard procedure to shut off any automatic pitch control, but somehow the pilots didn’t recognize that’s what was happening.
“MCAS had the wrong information and they reacted to that.,” he said. “MCAS is to blame.”
However, he cautions that there’s not enough information yet to know that the single AOA sensor failure triggered everything that happened, and that the entire sequence of events that led to the disaster won’t be clear until the investigation is completed. “It may not be as simple as a single sensor,” he said.
Nov 19, 2018, 5:45 am
#92
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Nov 20, 2018, 8:01 am
#93
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Nov 20, 2018, 1:38 pm
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Nov 23, 2018, 10:14 pm
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Nov 28, 2018, 4:39 pm
#96
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Latest info suggests the plane shouldn't have been approved by maintenance to fly following similar issues on previous flights. Also, apparently the crew on one of those previous flights did disable the MCAS, so it's unclear yet why the crew of the doomed flight failed to do so. The cockpit voice recorder has not yet been recovered.
Lion Air Jet Was 'Un-Airworthy' In Lead-Up To Fatal Crash, Investigators Say
Nov 29, 2018, 5:18 pm
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Preliminary report confirms crashed Lion Air MAX was not airworthy Safety content from ATWOnline
".....early findings by Indonesia National Transportation Safety Committee (NTSC) confirm that mechanics with Lion Air subsidiary Bantam Aero Technic, tasked with correcting problems on the aircraft, failed to do so. As a result, both the JT610 pilots and the crew that flew the aircraft’s previous flight—an Oct. 28 leg from Denpasar to Jakarta—were assigned aircraft that never should have flown."
".....early findings by Indonesia National Transportation Safety Committee (NTSC) confirm that mechanics with Lion Air subsidiary Bantam Aero Technic, tasked with correcting problems on the aircraft, failed to do so. As a result, both the JT610 pilots and the crew that flew the aircraft’s previous flight—an Oct. 28 leg from Denpasar to Jakarta—were assigned aircraft that never should have flown."
Nov 30, 2018, 6:53 am
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Nov 30, 2018, 8:14 am
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Dec 6, 2018, 12:44 am
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Dec 25, 2018, 11:38 pm
#102
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Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash
Crash investigators have concluded preliminarily that improper calibration of an airspeed sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.
The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board. Investigators also continue to delve into shortcomings discovered in the design of a new safety system on the plane.
I haven't heard this bit of info before:
Cockpit displays and a warning light intended to flag problems with angle-of-attack sensors in flight were optional on the Lion Air jet that crashed, according to people familiar with the matter. The carrier, like some others, chose not to purchase the feature, people familiar with the matter said, so pilots didn’t receive any such alerts. Some of the safeguards are standard on many older 737 models.
In recent weeks, Boeing, some of its customers and U.S. aviation authorities have discussed steps to ensure that 737 MAX pilots in the future will benefit from those safeguards, say many people in the industry.
In the U.S., Southwest Airlines , the launch customer for 737 MAX aircraft last year, will now have those options turned on each time it takes delivery of additional aircraft, a spokeswoman said. She also confirmed the carrier will retroactively install a Boeing-devised software change so that some two dozen aircraft already flying as part of the Southwest fleet eventually will get those added protections.
Crash investigators have concluded preliminarily that improper calibration of an airspeed sensor during maintenance touched off the sequence of events that led to October’s fatal Lion Air jetliner crash in Indonesia, according to people familiar with the details.
The conclusion is subject to further analysis, these people said, but it is the firmest indication so far that a suspected maintenance lapse was the initial misstep that ended with the months-old Boeing Co. 737 MAX aircraft plunging into the Java Sea, killing all 189 people on board. Investigators also continue to delve into shortcomings discovered in the design of a new safety system on the plane.
I haven't heard this bit of info before:
Cockpit displays and a warning light intended to flag problems with angle-of-attack sensors in flight were optional on the Lion Air jet that crashed, according to people familiar with the matter. The carrier, like some others, chose not to purchase the feature, people familiar with the matter said, so pilots didn’t receive any such alerts. Some of the safeguards are standard on many older 737 models.
In recent weeks, Boeing, some of its customers and U.S. aviation authorities have discussed steps to ensure that 737 MAX pilots in the future will benefit from those safeguards, say many people in the industry.
In the U.S., Southwest Airlines , the launch customer for 737 MAX aircraft last year, will now have those options turned on each time it takes delivery of additional aircraft, a spokeswoman said. She also confirmed the carrier will retroactively install a Boeing-devised software change so that some two dozen aircraft already flying as part of the Southwest fleet eventually will get those added protections.
Dec 26, 2018, 9:53 am
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NYTImes story. https://www.nytimes.com/interactive/...gtype=Homepage
Dec 27, 2018, 7:47 pm
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Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash
Cockpit displays and a warning light intended to flag problems with angle-of-attack sensors in flight were optional on the Lion Air jet that crashed, according to people familiar with the matter. The carrier, like some others, chose not to purchase the feature, people familiar with the matter said, so pilots didn’t receive any such alerts. Some of the safeguards are standard on many older 737 models.
Cockpit displays and a warning light intended to flag problems with angle-of-attack sensors in flight were optional on the Lion Air jet that crashed, according to people familiar with the matter. The carrier, like some others, chose not to purchase the feature, people familiar with the matter said, so pilots didn’t receive any such alerts. Some of the safeguards are standard on many older 737 models.