Citat:
Nja, jag tror att du missade den bit jag ville säga om "option", klipper in den nedanJag lyckades inte få din länk att fungera, men gissar att du menar detta:
theaircurrent.com/aviation-safety/the-world-pulls-the-andon-cord-on-the-737-max
Mycket intressant artikel!
Några citat (mina fetningar):
En del av historien bakom 737 MAX skulle jag kort sammanfatta så här.
– Airbus gjorde 380. Den var OK men för stor.
– Boeing gjorde Dreamliner. Den är OK men även den för stor. Och för dyr. Svår att få lönsam för både Boeing och köpare.
Marknaden vill ha mindre plan med två stolsrader (single isle). Airbus hade A320neo-familjen som passade många och blev en storsäljare. Boeings "svar" blev 737 MAX med moderna motorer, nya vinglets, ny tail och ny elektronik bl.a. Det var en genväg och nu ska vi snart se om Boeing lyckas visa att det var en lyckad genväg. Just nu ser det lite mörkt ut.
Går det att fixa svagheter när det gäller flygeneskaper, att den kan peka upp med nosen och stalla, med elektronik och programvara? Det är upp till Boeing att bevisa!
–
theaircurrent.com/aviation-safety/the-world-pulls-the-andon-cord-on-the-737-max
Mycket intressant artikel!
Några citat (mina fetningar):
«The 737 Max was born in the Admirals Club Lounge at Dallas-Fort Worth International Airport. On July 20, 2011, American Airlines was announcing it was buying 460 Airbus and Boeing aircraft to renew its fleet.»Jag fetade några delar som jag tyckte var speciellt intressanta.
...
«Every airplane development is a series of compromises, but to deliver the 737 Max with its promised fuel efficiency, Boeing had to fit 12 gallons into a 10 gallon jug.»
...
«In the case of the 737 Max, with its nose pointed high in the air, the larger engines – generating their own lift – nudged it even higher. The risk Boeing found through analysis and later flight testing was that under certain high-speed conditions both in wind-up turns and wings-level flight, that upward nudge created a greater risk of stalling. Its solution was MCAS, the Maneuvering Characteristics Augmentation System control law that would allow for both generations of 737 to behave the same way. MCAS would automatically trim the horizontal stabilizer to bring the nose down, activated with Angle of Attack data. It’s now at the center of the Lion Air investigation and stalking the periphery of the Ethiopian crash.»
...
«The point, made awkwardly by the President of the United States Tuesday morning on Twitter without naming Boeing directly, was that the complexity of aviation technology was being pushed too hard and at too great at cost of safety, all in the name of economics.
“Split second decisions are needed, and then complexity creates danger,” Trump wrote. “All of this for great cost yet very little gain.”
Boeing CEO Dennis Muilenburg reportedly spoke with President Trump earlier Tuesday, urging him not to ground the jet.
Lion Air 610 should never have been allowed to get airborne on October 29, a conclusion shared by those familiar with the inquiry. The plane simply wasn’t airworthy. According to the preliminary investigation, PK-LQP’s Angle of Attack sensors were disagreeing by 20-degrees as the aircraft taxied for takeoff. A warning light that would’ve alerted the crew to the disagreement wasn’t part of the added-cost optional package of equipment on Lion Air’s 737 Max aircraft. A guardrail wasn’t in place. Once the aircraft was airborne, the erroneous Angle of Attack data collided with an apparently unprepared crew with tragic consequences as the MCAS system repeatedly activated, driving the jet’s nose into a fatal dive.»
En del av historien bakom 737 MAX skulle jag kort sammanfatta så här.
– Airbus gjorde 380. Den var OK men för stor.
– Boeing gjorde Dreamliner. Den är OK men även den för stor. Och för dyr. Svår att få lönsam för både Boeing och köpare.
Marknaden vill ha mindre plan med två stolsrader (single isle). Airbus hade A320neo-familjen som passade många och blev en storsäljare. Boeings "svar" blev 737 MAX med moderna motorer, nya vinglets, ny tail och ny elektronik bl.a. Det var en genväg och nu ska vi snart se om Boeing lyckas visa att det var en lyckad genväg. Just nu ser det lite mörkt ut.
Går det att fixa svagheter när det gäller flygeneskaper, att den kan peka upp med nosen och stalla, med elektronik och programvara? Det är upp till Boeing att bevisa!
–
Nedan från http://www.airliners.net
"Boeing has an OPTIONAL module that will warn the pilots while they are still on the ground that the AoA sensors are not in agreement with each other. MCAS depended on AoA being correct. The reason the module is optional is to get around grandfathering laws. This was done even though the AoA is essential for the MCAS to work safely and Boeing did not provide adequate information on how MCAS worked and what the depencies were for it to work safely.
The fix for MCAS is to make it use more than one AoA sensor and not make the AoA a single point of failure.
Why did Boeing implement MCAS in the first place with such a basic safety weakness? The engineers must have known this was inherently flawed.
The culture at Boeing, as created by the management, is probably to blame and needs to be investigated."
