Hidden Danger Part 5 - Air Crash Investigation/Mayday

The rudder fails on a Boeing 737 operating as United Airlines Flight 585 and the aircraft spins out of control during approach to Colorado Springs, killing 25. Investigators are unable to determine the cause although they suspect a problem in the power control unit (PCU) which controls the rudder. Then three years later, another Boeing 737 flying as USAir Flight 427 crashes after a similar event during final approach. This time, the PCU survives intact but functions normally during testing. Two years on, Eastwind Airlines Flight 517 experiences two massive rolls to the right but the pilot is able to control the rolls and lands the 737 safely. This time an intact PCU is available for inspection. Investigations determine that thermal shock caused the rudders of the three aircraft to "hardover" and jam.

Category:

Education

Tags:

• United
• Airlines
• Flight
• 585
• USAir
• 427
• Eastwind
• 517

[geckodust]

hello, can i have a small request, i'm a big fan of these vids, however i can't really tell which part i would be clicking on the related videos as the title is too long and it turned into ... instead of telling me what part it is... i know it's some hard work, but it would be great if the parts are at the front of the title instead of the end. :)

[AirCrashMayday]

Sure

[geckodust]

thanks for the prompt reply, loving the vids :) (tho i don't like this narrator, the british one was much better imho)

[AirCrashMayday]

you like the english accent better?

[geckodust]

yep, this one you uploaded has a strange rhythm that sort of drives you to fall asleep..

[AirCrashMayday]

sorry bout that , I have no power to change it

[Darthbelal]

Hats off to the NTSB dudes who worked a very long, hard, arduous, tedious and perplexing case in trying to figure out why two 737s crashed. 737 pilots everywhere owe those guys a beer.

[ProtoCosmos]

At 30,000 Ft it's freezing no matter where you are.

[HACKERMASTERDESTROY]

seyyyy lets see the title says hidden danger eyyyy maybe the pilots can't control gravity so that it crashed Lol

[HACKERMASTERDESTROY]

@ProtoCosmos ya

[6Zebulon5]

@ProtoCosmos How very true

[methanbreather]

well another case of greed at Boeing killed people.

[ObsenityofAtomicTech]

Notice the hero in this whole thing is some unname guy that just happened to have a clue about what the hell was going on. If not for him telling them about a military test done on military aircraft we would still be seeing these planes falling out of the sky while the feds keep looking for scratches on shafts not even knowing metals are frozen in solid state and expand and contract with temp. Still can not get over them expecting the part maker to find the problem for them.

[ObsenityofAtomicTech]

I hope they got that value right this time ! Did anybody get put in jail for designing that piece of crap servo valve? Were the people in management involved in screwing up the design process by inserting there egos into the science of mechanical engineering costing hundreds of lives? Strange how the people in management get let off when they get people killed, hide in there offices with security gaurds and lawyer to cover there asses. This I am sure goes right to the top managers at boeing

[ObsenityofAtomicTech]

I wonder if that so called thermal shock has anything to do with clearences between bore and shaft of these valve spools. When you have a sliding part of bore and shaft of one or more layers there are mcroscopic differences between the bore ID, and the shaft OD called the clearance. Some machines are assembled using heated bores onto chilled shafts to get the tighest fit possible. As they equalize in temp the clearce disapears and the shaft and bore merge. Different temps equal bigger clearances

[MegaMaster456]

@AirCrashMayday take it from Nat Geo?

[antonmigr]

so why did it roll in the first place? and why did all those incidents happen only when the plane was approaching landing?