OV9

yikes

This could prove expensive for Boeing.....

They've fucked this right up. Because of the high bypass engines on the Max 8 they've been pushed forward and high up on the wing (for ground clearance). This has apparently affected the CofG and airflow over the wing, necessitating this bodged safety measure.

Simon wrote: Tue Mar 12, 2019 7:41 pm They've fucked this right up. Because of the high bypass engines on the Max 8 they've been pushed forward and high up on the wing (for ground clearance). This has apparently affected the CofG and airflow over the wing, necessitating this bodged safety measure.

Is that from the air accident investigators or aircraft forum experts?

Mito Man wrote: Tue Mar 12, 2019 7:49 pm

Simon wrote: Tue Mar 12, 2019 7:41 pm They've fucked this right up. Because of the high bypass engines on the Max 8 they've been pushed forward and high up on the wing (for ground clearance). This has apparently affected the CofG and airflow over the wing, necessitating this bodged safety measure.

Is that from the air accident investigators or aircraft forum experts?

No, it’s Boeing’s explanation for why they introduced the MCAS system, which is believed to be responsible for the Lion Air crash, which followed the same flight pattern as this crash.

Their stock took a big hit. Wonder if there are penalties in their contracts if the planes prove not to be air worthy within a "warranty" period.

Statistically, the 737 Max 8 now has the worst safety record of any newly launched airliner since the DeHaviland Comet, which kept falling out of the sky because the windows were the wrong shape.

The MCAS system - or more specifically the fact that it’s automatic and unannounced intervention doesn’t appear to have been properly explained/documented as part of flight crew training - seems rather strange.

Would be interesting to get IanF’s opinion on that (if you are able to share it of course Ian)..

Doesn't Ian fly Airbus?

I drive an Audi but still know quite a lot about Porsches

mik wrote: Wed Mar 13, 2019 12:08 am The MCAS system - or more specifically the fact that it’s automatic and unannounced intervention doesn’t appear to have been properly explained/documented as part of flight crew training - seems rather strange.

Would be interesting to get IanF’s opinion on that (if you are able to share it of course Ian)..

They introduced MCAS in order to automatically compensate for the handling difference due to the larger engines so that pilots who already had their 737NG rating wouldn’t need to be retrained, which is a massive advantage. Even the override procedure is the same as overriding the autotrim on a 737NG, and MCAS is basically just a fancy autotrim.

What they hadn’t factored in was MCAS doing something odd, and pilots not understanding wtf was going on. It’s like a car manufacturer knowing their car veers right on the brakes, so they make it automatically apply some left steering whenever you brake, but then it sometimes applies some left steering without the brakes being applied. If you know it’s coming, you can drive round it, but if it suddenly happens you might end up fucked.

Did you intentionally post at 737 Dave?

More light reading here https://theaircurrent.com/aviation-safe ... cas-jt610/

The must surprising thing to me is that moving the engines forward causes the pitch to go up a little.

Broccers wrote: Wed Mar 13, 2019 8:50 am Did you intentionally post at 737 Dave?

NotoriousREV wrote: Wed Mar 13, 2019 7:37 amWhat they hadn’t factored in was MCAS doing something odd, and pilots not understanding wtf was going on. It’s like a car manufacturer knowing their car veers right on the brakes, so they make it automatically apply some left steering whenever you brake, but then it sometimes applies some left steering without the brakes being applied. If you know it’s coming, you can drive round it, but if it suddenly happens you might end up fucked.

From an outsider's point of view, it sounds like Boeing have their arse exposed right out in the wind on this one. Interesting to see how it pans out.

Mito Man wrote: Wed Mar 13, 2019 9:06 am The must surprising thing to me is that moving the engines forward causes the pitch to go up a little.

Engines are below and ahead of the Centre Of Lift. (Which is always behind the Centre Of Gravity on commercial planes for stability reason). Thrust therefore pitches the nose up. Mount them lower or further forward and the “lever” increases, so the pitch effect under power increases.

The worrying part of that link is Boeing decided against providing Pilots with more detailed information on the system to prevent "Average Pilots" getting confused

What sort of people are flying these things

mik wrote: Wed Mar 13, 2019 9:45 am

Mito Man wrote: Wed Mar 13, 2019 9:06 am The must surprising thing to me is that moving the engines forward causes the pitch to go up a little.

Engines are below and ahead of the Centre Of Lift. (Which is always behind the Centre Of Gravity on commercial planes for stability reason). Thrust therefore pitches the nose up. Mount them lower or further forward and the “lever” increases, so the pitch effect under power increases.

It must be an odd sensation when they idle engines coming in to land! Although I guess the computer sorts out the pitch so it feels ‘normal’.

Carlos wrote: Wed Mar 13, 2019 10:19 am The worrying part of that link is Boeing decided against providing Pilots with more detailed information on the system to prevent "Average Pilots" getting confused

What sort of people are flying these things

Don't forget, AF447 was a perfectly serviceable aircraft was flown into the sea due, partly, to the fact the FO just kept pulling full back on the stick whilst the stall warning went off for nearly a minute. I'm not a pilot, but even I know that there's not many situations where that's going to be the correct answer.

mik wrote: Wed Mar 13, 2019 9:14 am

Broccers wrote: Wed Mar 13, 2019 8:50 am Did you intentionally post at 737 Dave?

Sure, why not?