Larger diameter engines which are more efficient. I think some more passenger room. Move more people using less fuel, that is the name of the game.
What issues or inefficiencies did the Maxx 8's predecessors have that required the new designs now in question?
The larger diameter engine was mounted further fwd , which with a very light aircraft and way aft CG exposed enough engine cowling bottom to add to the normal pitch change of adding power.
COPIED From Aviation Week 20 May page 24
" When we looked at JT 610 data and realized that the flight data showed the runaway pitch trim procedure WAS NOT DONE ...we knew that this needs to be emphasized"
" The ET 302 crew depowered the stabilizer trim motors , but did not counter the MCAS inputs with electric trim inputs before hand. They turned the motors back on , which the stabilizer runaway procedure says should NOT be done . This reactivated the MCAS and lead to an uncontrollable dive."
Flip the "stab cutout " switches to OFF and fly with the hand trim wheel as gramps did , problem solved.
This is a MEMORY procedure!!!
Except that with the MCAS system it is reported that as long as the pilots use the electric trim switches then the MCAS was inhibited for a few seconds after the switch was released. It would seem to me that all they had to do was keep retrimming the airplane every time the MCAS started moving the trim. I would've thought that the first thing to do when the airplane goes out of trim is to trim it back. It would be annoying and might not have made for the smoothest flight, but it should have worked.
I think that's correct, provided you know that MCAS is there and that it's the cause of the problem. And that you know that manual trim actions disable it for a little while. But by all indications, the pilots didn't know that, because they were never told. That's where the Boeing/FAA part of the problem starts to rear it's head.
CHICAGO, May 16, 2019 – Boeing has completed development of the updated software for the 737 MAX, along with associated simulator testing and the company’s engineering test flight. To date, Boeing has flown the 737 MAX with updated MCAS software for more than 360 hours on 207 flights.
Boeing is now providing additional information to address Federal Aviation Administration (FAA) requests that include detail on how pilots interact with the airplane controls and displays in different flight scenarios. Once the requests are addressed, Boeing will work with the FAA to schedule its certification test flight and submit final certification documentation.
MCAS is designed to activate in manual flight, with the airplane’s flaps up, at an elevated Angle of Attack (AOA).
Boeing has developed an MCAS software update to provide additional layers of protection if the AOA sensors provide erroneous data. The software was put through hundreds of hours of analysis, laboratory testing, verification in a simulator and two test flights, including an in-flight certification test with Federal Aviation Administration (FAA) representatives on board as observers.
The additional layers of protection include:
- Flight control system will now compare inputs from both AOA sensors. If the sensors disagree by 5.5 degrees or more with the flaps retracted, MCAS will not activate. An indicator on the flight deck display will alert the pilots.
- If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.
- MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.
Since they pretty much hobbled MCAS, seems that the next question should be "Is MCAS really necessary at all?"
My non-pilot guess is that MCAS was not necessary at all. It was only there so the Max was similar enough to previous models that it could be considered "in type". Not that MCAS was needed to make the AC safe, but to make it less different.
If it wasn't for how the rules were structured, MCAS probably would never have been there.
What a mess. Hopefully will get this sorted soon.
No idea about accuracy, but it sure qualifies as QI(quite interesting)
https://mattstoller.substack.com/p/the-coming-boeing-bailout
The right policy path would be Congressional hearings to explore what happened to this once fine company
The right policy path would be Congressional hearings to explore what happened to this once fine company
" The 737 started coming off the assembly line in 1967, and it was such a good design it was still the company’s top moneymaker thirty years later."
The first ones coming off the line could not go from LGA to ORD (NYC to Chicago)in bad winter conditions with out naming a fuel stop.
THe pilots called them FLUF, Fat Little Ugly Fellow ( last name changed to protect the kids)
The "good design " is now, transatlantic , no sweat.
IF anyone is interested this weeks issue of Aviation Week has a great in depth article on the MAX mess.
Airbus has its issues too. Read up on Air France 447 that crashed in the Atlantic after pitot tubes iced up and the automation didn't have enough data to prevent an aerodynamic stall.
Air France Flight 447 and the safety paradox of airline automation on 99 Percent Invisible.
I don't fly these planes, as the Lear I fly has "delta fins" on the tail that provide enough lift in deep stall situations to push the tail up and "unstall" the wing if you will. At least it starts the pitch motion in the right direction. Its a super simple system that works on a smaller jet.
But I have many friend who fly the Airbus and they indicate that if the computer looses a sensor (airspeed/pitot) it will degrade to a lower level and basically "you are now flying the aircraft." So pitch and bank angle protections might not be there. From what I read the pilot in the right seat pulled the side stick fully aft and in normal "law" the plane should pitch to a maximum angle of attack and advance the auto throttles to prevent a stall. But they had flown through severe icing conditions at the top of a thunderstorm and iced up the pitot tubes.
My point being they relied on automation when it wasn't there. An otherwise perfectly good airplane was flown in a stalled condition with plenty of room to recover from the stall - if the crew had only realized it was stalled and acted on basic training from their early days of flying. Lower the nose and regain lift over the wing.
Boeing will get it right - but I agree the pilots need more simulator training on a newer aircraft. Most US pilots got an hour training program on an iPad.