CargoLux 747 loses Main Gear

[ASpilot2be]

I wouldn't say they lost it. Only misplaced it.

 

[Pilot Fighter]

Sometimes I wish I had mo’ main gear.

 

[inigo88]

There is a sequence valve (shuttle valve) that positions the gear for retraction position and extension position (I forget the terminology). The valve, actuator, or linkage probably failed preventing proper retraction.

Upon landing it would cause a position where the truck angle would not be dampened upon touchdown and cause an oscillation or bounce possibly overstressing and causing separation.

Just a guess. Could have been socialism....

I think it’s a reasonable guess. Somewhere I have a PowerPoint reverse engineering the B744 landing gear schematic flow sequence for… reasons… I recall there being like 7 steps in the sequence where hydraulic fluid flows back and forth based on multiple servo valves (the original valve is actuated from the landing gear handle but there are subsequent ones downstream as well), uplock/downlock position changes and electrical limit switches. If any of those limit switches are out of rig the process can stall out on like step 4 out of 7 and then you never complete the retraction or extension process. As far as the truck angle I do remember a truck position actuator that sets the proper angle for landing during gear extension, but I’ve never heard of the failure mode where the main gear flies off if the truck angle is wrong. I’m also not very up to speed on 747 accidents and incidents though so maybe it has happened.

Here is an appropriately nerdy video:

View: https://youtu.be/Zk42p1zMnbM

 

[DropTank]

I think it’s a reasonable guess. Somewhere I have a PowerPoint reverse engineering the B744 landing gear schematic flow sequence for… reasons… I recall there being like 7 steps in the sequence where hydraulic fluid flows back and forth based on multiple servo valves (the original valve is actuated from the landing gear handle but there are subsequent ones downstream as well), uplock/downlock position changes and electrical limit switches. If any of those limit switches are out of rig the process can stall out on like step 4 out of 7 and then you never complete the retraction or extension process. As far as the truck angle I do remember a truck position actuator that sets the proper angle for landing during gear extension, but I’ve never heard of the failure mode where the main gear flies off if the truck angle is wrong. I’m also not very up to speed on 747 accidents and incidents though so maybe it has happened.

Here is an appropriately nerdy video:

View: https://youtu.be/Zk42p1zMnbM

NERRRRRRRRRRRRRRRRRRRRRRRRRD!!

Just kidding. Awesome post!

 

[mrivc211]

Aircraft is LX-OCV, has always been with Cargolux, and is 23.9 years old.

My understanding is 744 structural D-checks occur on an 8/8/6 schedule (8 years, 16 years, 22 years?). I have no specific information about the maintenance history of this specific aircraft.

I wouldn't be shocked if its written off. The other mains had to pick up the load so theres a good chance theres bends/wrinkles. From the looks of the pictures, theres tons of airframe work to be done. Not looking good for this bird thats for sure.

 

[SFCC/UND]

I wouldn't be shocked if its written off. The other mains had to pick up the load so theres a good chance theres bends/wrinkles. From the looks of the pictures, theres tons of airframe work to be done. Not looking good for this bird thats for sure.

I dunno, when I was at K4 one of our 74's hit a dumpster during takeoff. Left a trail of damage from the nose to the tail. They patched it up in a couple months and had it flying again.

 

[derg]

Redefined "slingin' the gear". Yuk. Yuk. Oh, I kill me.

 

[mrivc211]

I dunno, when I was at K4 one of our 74's hit a dumpster during takeoff. Left a trail of damage from the nose to the tail. They patched it up in a couple months and had it flying again.

What the heck was a dumpster doing on a runway lol

 

[Skåning]

What the heck was a dumpster doing on a runway lol

Taking out the trash!

 

[CFI A&P]

What the heck was a dumpster doing on a runway lol

Is this a joke about Spirit or Southwest ?

 

[CFI A&P]

I wouldn't be shocked if its written off. The other mains had to pick up the load so theres a good chance theres bends/wrinkles. From the looks of the pictures, theres tons of airframe work to be done. Not looking good for this bird thats for sure.

It is a hard guess without knowing the cycles & hours on. Then again, with the 747 out of production, it is probably very lucrative to keep it flying.

 

[thepotato232]

Is this a joke about Spirit or Southwest ?

Actually, we were told it blew over from the Delta ramp...

Accident Boeing 747-412 (BCF) N703CK,

Kalitta Air Flight 368, a Boeing 747-412BCF, struck a trash bin on takeoff from runway 25R at Los Angeles Airport, USA. The takeoff was aborted and the aircraft came to a stop on the runw...

aviation-safety.net

 

[inigo88]

Actually, we were told it blew over from the Delta ramp...

Accident Boeing 747-412 (BCF) N703CK,

Kalitta Air Flight 368, a Boeing 747-412BCF, struck a trash bin on takeoff from runway 25R at Los Angeles Airport, USA. The takeoff was aborted and the aircraft came to a stop on the runw...

aviation-safety.net

Ah man I had a feeling it was LAX!