Azerbaijan Airlines plane crashes in Kazakhstan (1 Viewer)

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

And on the topic of aircraft losing hydraulics because of shrapnel damage, thanks to a previous accident all modern aircraft have redundancy and failsafes built into them.

United Flight 232, a DC-10crash landed in 1989 at Sioux Gateway Airport in Sioux City, Iowa, after suffering a catastrophic failure of its tail-mounted engine due to an unnoticed manufacturing defect in the engine's fan disk, which resulted in the loss of all flight controls. Of the 296 passengers and crew on board, 112 died during the accident, while 184 people survived.


Since then all airline manufacturers design hydraulic fuses that isolate systems to prevent total loss of hydraulics power, and no longer route hydraulic systems together so that the likelihood of all three systems failing is rare.
 
I thought the doors needed juice to open. This is why I don't work for the FAA.

Nope, there is a mechanical extension for emergencies. And…

Gravity

On the aircraft I would perform tests on, the uplocks would mechanically disengage, allowing the gear to swing down with gravity, and then a mechanical handle was used to move the gear the rest of the way into the downlock position. There are other aircraft with emergency hydraulic reservoir's not part of the regular system just to extend the gear as well.
 
Gear does not require hydraulics to be extended.

I used to do emergency extension tests all the time on aircraft jacked up on the hangar floor.

Emergency extension without hydraulic or electric power is a certification requirement on all transport aircraft. On some the crew must use a hand crank and a winch built into the floor to close the main gear doors enough to prevent them dragging on the runway.
 
Last edited:

and to prevent loss of hydraulic power when one engine is shut down or one system pump fails there are units that use the other (or another) engines system to drive one or more pumps in the system that has lost its normal pressure source.
 
and to prevent loss of hydraulic power when one engine is shut down or one system pump fails there are units that use the other (or another) engines system to drive one or more pumps in the system that has lost its normal pressure source.

Absolutely, and all of these redundancies and designs are designed in blood.
 
Per this Embraer 190 training vid (at about 36:45), they have a mechanical override for freefalling the landing gear:

View: https://www.youtube.com/watch?v=B-wPhSECeO4
In most aircraft I'm familiar with, you can tell if the mechanical override was used because the landing gear doors won't come up afterward. I can't tell from that video, but I don't see any obvious hanging doors.
 

Users who are viewing this thread