ET302 crash taking off
Posted: Sun Mar 10, 2019 9:01 pm
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https://www.cbsnews.com/news/ethiopian-plane-crash-flight-et-302-crashes-minutes-after-takeoff-boeing-737-8-max-live-updates-2019-03-10/ wrote:In October, another Boeing 737-8 MAX plunged into the Java Sea just minutes after taking off from Jakarta, Indonesia's capital, killing all 189 people on board the plane Lion Air flight. The cockpit data recorder showed that the jet's airspeed indicator had malfunctioned on its last four flights, though Lion Air initially claimed that problems with the aircraft had been fixed.
IAHM-COL wrote:eerily, these two crashes are similar enough to be hair-rising.
For the past several months and in the aftermath of Lion Air Flight 610, Boeing has been developing a flight control software enhancement for the 737 MAX, designed to make an already safe aircraft even safer. This includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.
V12 wrote:Why the hell is automatic system "stronger" than pilot's input ?
IAHM-COL wrote:V12 wrote:Why the hell is automatic system "stronger" than pilot's input ?
The ages old question of whether the philosophy behind "fly-by-wire" or "die-by wire" technology is fundamentally sound, or not.
I had assumed that the AoA source for MCAS was always the Captains AoA probe but the following explanation from an engineer suggests that it alternates between AoA probes each flight:
MCAS is implemented within the two Flight Control Computers (FCCs). The Left FCC uses the Left AOA sensor for MCAS and the Right FCC uses the Right AOA sensor for MCAS. Only one FCC operates at a time to provide MCAS commands. With electrical power to the FCCs maintained, the unit that provides MCAS changes between flights. In this manner, the AOA sensor that is used for MCAS changes with each flight.
https://www.latimes.com/politics/la-na-pol-trump-ground-boeing-max-20190313-story.html wrote:President Trump grounded Boeing’s 737 Max planes Wednesday, following the lead of 51 other countries that have ordered an indefinite freeze on flying the model involved in two calamitous crashes.
https://www.latimes.com/politics/la-na-pol-trump-ground-boeing-max-20190313-story.html wrote:The union for American’s pilots, the Allied Pilots Assn., said Tuesday that American’s 737 Max planes are unique because they are the only ones equipped with two displays, one for each pilot, related to the software in question. That provides “an extra layer of awareness and warning,” the union said.