Boeing accidents

[Bayless]

What I can't understand is why was it necessary to take a perfectly balanced aircraft and ad bigger engines which made it inherently unstable?

 

[NutmegCT]

What I can't understand is why was it necessary to take a perfectly balanced aircraft and ad bigger engines which made it inherently unstable?

Bigger engines allow enlargement of fuselage for more passengers!

 

[TR3driver]

IIRC, it was because the physically larger engines are more fuel efficient. That both increases range and lowers operating costs, making it more competitive with other newer aircraft designs. They also can produce more thrust than the previous engines. The fuselage was slightly reshaped and slightly longer, but again mostly to reduce fuel consumption and improve range.

Passenger capacity is actually the same as the previous 737-900ER, but range increased by roughly 20%.

PS see https://www.b737.org.uk/737maxdiffs.htm for more info about the mods.
Here's another comparison with the 737-800
https://www.aviatorjoe.net/go/compare/737-800/737_MAX_8/

 

[NutmegCT]

Randall - those are the best descriptions of the 737 MAX variants I've seen. Thanks for posting the links.
Tom M.

 

[70herald]

The larger diameter engines are more efficient. The problem on the 737 is that the diameter has gotten so large that the engines are now scraping the ground.
Boeing apparently looked into increasing the height of the plane when on the ground but that required redesigning the landing gear. Basically they are dealing with a 50 year old design decision on landing gear height

 

[John Turney]

...
It's also amazing how often the decision to ship product is made by management over objections from engineering. Then when it turns out to really not work, it's usually cast as engineering's fault.
https://www.nytimes.com/2012/02/04/us/roger-boisjoly-73-dies-warned-of-shuttle-danger.html

It certainly keeps Scott Adams (Dilbert) in business.

 

[Bob McElwee]

There was an episode on Smithsonian channel Air Disaster program tonight with the Airbus 330 (?) concerting a system malfunction. The symptom was the automated safety system 'thought' the plane was climbing and put the plane in a steep dive to correct. Problem was the plane was in level flight. The safety function also locked out any manual inputs from the pilot. The investigators eventually found the binary code of the source problem, the airspeed and altitude data(I think) got transposed by one other the three subsystems and confused the main autopilot system. (not a good explanation, I know).
The 'good' news was this happened at 37,000 feet and the pilots eventually got control of the plane and landed safely.
I am expecting the Boeing crashes to make the program some day.

 

[Deleted member 8987]

There was an episode on Smithsonian channel Air Disaster program tonight with the Airbus 330 (?) concerting a system malfunction. The symptom was the automated safety system 'thought' the plane was climbing and put the plane in a steep dive to correct. Problem was the plane was in level flight. The safety function also locked out any manual inputs from the pilot. The investigators eventually found the binary code of the source problem, the airspeed and altitude data(I think) got transposed by one other the three subsystems and confused the main autopilot system. (not a good explanation, I know).
The 'good' news was this happened at 37,000 feet and the pilots eventually got control of the plane and landed safely.
I am expecting the Boeing crashes to make the program some day.

Saw it.
Question:
You think the timing of the airing (or re-airing) was an accident?

 

[Bob McElwee]

TOC, that thought crossed my mind when the researching the problem got the the automated systems. It seems like this was some time ago so it very well may have been a re-airing. I do enjoy the show.

 

[DNK]

[FONT=&quot]https://airfactsjournal.com/2019/03/can-boeing-trust-pilots/

[/FONT]

 

[glemon]

I read this today linked from another site, same basic story is repeated on a number of news sites. https://www.google.com/amp/s/www.se...ystem-implicated-in-the-lion-air-crash/?amp=1

Three things stuck out to me, system relies on a single sensor, system corrects at four times the initial certified angle of adjustment on the stabilizer, system resets itself quickly if pilot tries to manually override.

Pure armchair hillbilly observations, seat of the pants it feels like commercial jets seem to climb at a much steeper angle than they did 20-30 years ago. If true is this because they have the stall alarms and autopiloting features to try to eliminate stalls so they fly closer to the limit? Better low speed power and efficiency of modern turbojets? Traffic concerns? I am totally off base, they climb like they always did?

If in fact this system relies on one sensor, why? Surely there is more than one way to sense that a plane is climbing vs. diving? Gaining altitude vs. losing? Wouldn't a modern plane have sophisticated enough systems to integrate this data from multiple sources and adjust accordingly? Isn't that basically what autopilot does now?

 

[DavidApp]

I think there are 2 of the angle of attack sensors one on each side of the aircraft and it seems there may have been a disagreement between the 2 sensors indicating different angles of attack..
Seems that they are easily damaged when the aircraft is on the ground so a backup system or a way of verifying the information would seem like a good idea.

David

 

[GregW]

it feels like commercial jets seem to climb at a much steeper angle than they did 20-30 years ago.

Planes outta' Burbank climb steeply to keep noise down for the city, except for the area right around the airport where I think it is even louder than if they used a shallow climb rate.

 

[TR3driver]

Pure armchair hillbilly observations, seat of the pants it feels like commercial jets seem to climb at a much steeper angle than they did 20-30 years ago. If true is this because they have the stall alarms and autopiloting features to try to eliminate stalls so they fly closer to the limit? Better low speed power and efficiency of modern turbojets? Traffic concerns? I am totally off base, they climb like they always did?

I believe it is mostly to reduce noise pollution to the surrounding neighborhoods. Sound follows an inverse square law, doubling the distance cuts the noise level by 75% (-6db). So the quicker they get up in the air, the less noise is heard on the ground.

Some areas actually have noise rules; climbing too slow can put you in violation. A friend of mine used to build noise monitoring systems that would ultimately link back to which flight and which pilot violated the rules.

 

[Popeye]

https://qph.fs.quoracdn.net/main-qimg-f5b0df04f344fb44ce7b3a6dc98d49ff

 

[DavidApp]

Even the old ones do that.

David

https://blog.virginatlantic.com/wp-content/uploads/2017/01/BC103-759x1024.jpeg

 

[Popeye]

Sustained? Impressive!

 

[DavidApp]

I saw one taking off in England. The Lightening was still in operational service at the time We were standing by the airfield fence only a few 100 feet away. Still remember the diamond shock waves in exhaust at the pilot engaged the afterburner. The noise was a physical thing and probable was not the best thing for young ears.

David

 

[SaxMan]

Some may recall that when the 727 first came out, there were several crashes. Pilots were trying to fly the plane "by the seat of their pants" rather than following the manual. Better training resulted in the 727 going on to have a very good safety record.

Even back in the days of propliners, there was a national concern when three DC-4s crashed in about a week's time in 1946.

 

[DrEntropy]

https://qph.fs.quoracdn.net/main-qimg-f5b0df04f344fb44ce7b3a6dc98d49ff

One of my first performance aircraft rides! T-38 Talon.