737 Max first flight

[mako88sb]

Looks pretty neat with the new style winglets which has caused some people to nickname it the X-wing.

[Jimbuna]

Very nice, I should imagine young Buna will book a flight if and when BA get some.

[Tchocky]

BA are likely to stick with Airbus for future short-haul. Although 737-MAX has been selling quite well so I'm sure he'll end up on one somewhere!

[Commander Wallace]

Awesome first flight of the revised 737.

The Boeing 737 aircraft has had something of a checkered past. The 737 had an issue with it's rudder control servos resulting in crashes of US Air flight 427 and United Airlines flight 585 and the loss of all aboard. These are just a few of the crashes involving the 737 although they are from various causes.

Quote : The National Transportation Safety Board determines that the probable cause of the USAir Flight 427 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blow down limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and over travel of the primary slide.

https://en.wikipedia.org/wiki/USAir_Flight_427


https://en.wikipedia.org/wiki/United_Airlines_Flight_585

http://airlinesafety.com/faq/B-737Rudder.htm


http://www.airsafe.com/events/models/b737.htm
( List of 737 crashes with at least one fatality )

I hope for the safety and well being of the passengers flying aboard this class of aircraft that these issues have been corrected and the corrections fully implemented.

[mako88sb]

Originally Posted by Commander Wallace

Awesome first flight of the revised 737.

The Boeing 737 aircraft has had something of a checkered past. The 737 had an issue with it's rudder control servos resulting in crashes of US Air flight 427 and United Airlines flight 585 and the loss of all aboard. These are just a few of the crashes involving the 737 although they are from various causes.

Quote : The National Transportation Safety Board determines that the probable cause of the USAir Flight 427 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blow down limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and over travel of the primary slide.

https://en.wikipedia.org/wiki/USAir_Flight_427


https://en.wikipedia.org/wiki/United_Airlines_Flight_585

http://airlinesafety.com/faq/B-737Rudder.htm


http://www.airsafe.com/events/models/b737.htm
( List of 737 crashes with at least one fatality )

I hope for the safety and well being of the passengers flying aboard this class of aircraft that these issues have been corrected and the corrections fully implemented.

There was a Mayday episode about the faulty rudder power control unit that was very sporadic and very difficult to duplicate in the testing facility. It wasn't until they cooled the pcu to -40 F and thermal shocked it with fairly hot hydraulic fluid that they were able to isolate the problem. It was corrected throughout the entire 737 fleet which at that time was thousands of planes. Anyway, the safety statistics for the 737 show it to be a very safe aircraft. Most of the incidents on your link have nothing to do with it's design.
http://www.airsafe.com/events/models/rate_mod.htm

[Commander Wallace]

Originally Posted by mako88sb

There was a Mayday episode about the faulty rudder power control unit that was very sporadic and very difficult to duplicate in the testing facility. It wasn't until they cooled the pcu to -40 F and thermal shocked it with fairly hot hydraulic fluid that they were able to isolate the problem. It was corrected throughout the entire 737 fleet which at that time was thousands of planes. Anyway, the safety statistics for the 737 show it to be a very safe aircraft. Most of the incidents on your link have nothing to do with it's design.
http://www.airsafe.com/events/models/rate_mod.htm

The design of the 737 as you said was sound. It is in wide use, worldwide. The NTSB was slow however with it's finding and rectification of the problems. The identification of the issue as you described was also in the links I listed.

Flight 585 went down march 3, 1991 and flight 427 in September 8, 1994. The crashes in both cases resulted from defective servo controls for the rudders. The crash of flight 427 and the tragic loss of 132 people might have been avoided had the seriousness of the situation been recognized as an inherent problem with the servo and not an anomaly.

I have flown many times on the 737 and liked the aircraft however, my plane didn't go down either.

[Gargamel]

But again, is it poor design, or poor maintenance? Most structural/control failures are from poor maintenance, not design.

I'm curious as to the advantage of the lower winglet. I understand the upper winglet keeps the airflow on the lifting surface, making the entire wing vastly more effecient, but I'm not clear on what the lower one does.

and I've been binging a bit on aircraft videos of late (The ATC ones with subtitles are my current fetish), and I've seen that little parachute thingy on a few planes. Whats with that?

[Tchocky]

Originally Posted by Gargamel

and I've been binging a bit on aircraft videos of late (The ATC ones with subtitles are my current fetish)

I knew you people were out there!

I understand the upper winglet keeps the airflow on the lifting surface, making the entire wing vastly more effecient, but I'm not clear on what the lower one does.

More or less the same function, preventing and then delaying airflow separation and acting as a lightweight wingspan extension. Both of which give you a boost.

[Commander Wallace]

[QUOTE=Gargamel;2382010]But again, is it poor design, or poor maintenance? Most structural/control failures are from poor maintenance, not design.

I think in this case since the servos were redesigned and updated, it was an unseen problem unrelated to maintenance. I'm sure Subsim members in the aviation industry or people with an interest in aircraft like Golden Rivet and others would have a better understanding or insight into how maintenance is carried out. As mako88sb said, changes were made to the surviving aircraft and I'm sure service bulletins were issued to other countries operating the 737 regarding replacement of the offending parts once the problems were known.