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29erUSA187
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Procedure In A Landing Gear Failure

Mon Jan 19, 2015 8:01 pm

Hello All,
I was just wondering what would happen to a plane with only 3 sets of gear if one of the two main struts failed (god forbid this ever happens)

I know that with the VS 744 at LGW, the 744 has 4 main wheel structures, so it was landed with 2 on one side and only one on the other.

Now, lets say a 737 has a similar problem. If they landed with the gear down, there would be no gear on one side, and the engine would hit ground. Would they attempt to land like this and risk swerving off the runway, or would they risk a belly landing like the LOT 763 in WAW a few years back?

Any input would be appreciated,

-29er
 
barney captain
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RE: Procedure In A Landing Gear Failure

Mon Jan 19, 2015 8:06 pm

https://www.youtube.com/watch?v=WD-bcocienM


There have been several 737 landings with MLG failures. Our procedures require using all available down gear to absorb touchdown and differential braking to maintain control.

The one thing we are not to do is arm the speed brakes - as was done in the video above. You can see why - as soon as the one MLG touched down, the speed brakes deployed causing the other wing/nacelle to slam down on the runway. This is not a desirable state.

[Edited 2015-01-19 12:15:36]

[Edited 2015-01-19 12:16:25]
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29erUSA187
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RE: Procedure In A Landing Gear Failure

Mon Jan 19, 2015 8:13 pm

Wow that had to be scary! Thanks for showing me that. Are there any other videos out there like that?
 
bueb0g
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RE: Procedure In A Landing Gear Failure

Mon Jan 19, 2015 8:51 pm

Both Boeing and Airbus recommend landing with all available gear. This can however lead to a loss of directional control and, especially in 4 holers, the risk of engine contact with the runway.

This is a problem than a Virgin Atlantic A340 crew at Heathrow in the late 90's had to deal with, and the Airbus procedures were not very helpful, so the commander modified them on the spot. The crew's changes were later incorporated into Airbus's own recommended procedures. The report is an interesting read:

http://www.aaib.gov.uk/cms_resources.cfm?file=/4-2000%20G-VSKY.pdf

And here's a video of the landing:

https://www.youtube.com/watch?v=NprTbTVl1Uk
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simairlinenet
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RE: Procedure In A Landing Gear Failure

Thu Jan 22, 2015 3:22 pm

Very old guidance (1970s? article from Boeing):
-If you lose the nose gear, land on the mains and hold off the nose as long as possible
-If you lose one main gear, angle the landing (and passengers if possible) to the side with the gear
-If you lose both main gears, land on the belly

Based on the above, it appears the thinking has changed over the decades.
 
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flyingturtle
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RE: Procedure In A Landing Gear Failure

Thu Jan 22, 2015 5:07 pm

http://www.youtube.com/watch?v=2gmpbua5N0E is another one.

Quoting simairlinenet (Reply 4):
-If you lose the nose gear, land on the mains and hold off the nose as long as possible

With the important point that you should plant the nose on the runway as long as you still got elevator authority, which requires speed. You want to touch down with the nose in a controlled way - not with a loud crash.

Reverse thrust and air brakes (ground spoilers) are not used if you land with one or two MLG disabled. Fuel to the engines is to be cut off immediately before they touch the ground.


David
Reading accident reports is what calms me down
 
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litz
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RE: Procedure In A Landing Gear Failure

Thu Jan 22, 2015 6:06 pm

Don't forget, that aircraft are designed to take into account the possibility of a LG failure, up to (and including) a full failure of all three components of the tricycle carriage.

LOT's 767 is a perfect example.

In this extreme case, even this airframe was repairable, it just wasn't economical to do so.
 
wingscrubber
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RE: Procedure In A Landing Gear Failure

Sun Feb 01, 2015 10:49 pm

This sort of failure happened to A320 a few times due to the door actuators jamming. Fortunately this issue is all sorted now they got rid of all the bad door actuators and implemented an effective AD.

http://news.aviation-safety.net/2013...idents-prompt-tougher-inspections/
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rfields5421
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RE: Procedure In A Landing Gear Failure

Sun Feb 01, 2015 11:29 pm

Quoting simairlinenet (Reply 4):
Very old guidance (1970s? article from Boeing):
-If you lose the nose gear, land on the mains and hold off the nose as long as possible
-If you lose one main gear, angle the landing (and passengers if possible) to the side with the gear
-If you lose both main gears, land on the belly

I've seen that in NATOPS manuals for C-121 (Super Connie) and C-118 (DC-6) aircraft. It has long been the preferred method of dealing with a gear failure.

As mentioned above -

Quoting barney captain (Reply 1):
procedures require using all available down gear to absorb touchdown

Touchdowns are seldom - smooth as glass - especially in emergencies. The gear is needed to cushion the impact. Then gently lower the ungeared part of the aircraft to contact the runway.

The risk of a hard impact which breaks the fuselage is too great.

---------------

That said - sometimes unique ideas are used and are successful.

In early 1974 I was cleaning out some old file cabinets in an office in my squadron - and came across several spools of 16mm film. They were film shot of accidents the squadron had had over the years.

One film showed a C-121 with the nose gear frozed at a 45 degree angle. The film showed two low passes past the tower, two hard bounce TNG landings on the main gear, and the final landing. In the final landing - the pilots rotated the aircraft back until the tail made contact with the runway. The plane slowed to a stop DC-3 style. The reports in the file cabinet explained that there was worry about the plane tipping over. The C-121 is very tail heavy compared to many aircraft. During the landing most of the passengers - military dependent wives - were standing in area of the wing. As the plane slowed the flight engineer sent more and more to the rear of the plane to make it tail heavy. The airport - NAF Atsugi - was ready with a truck padded with mattresses which was quickly run under the plane to keep it from falling over on the nose, and ropes tied to heavy GSE were thrown over the aft fuselage. No one should make up a procedure on the fly - this evolution from the first normal gear lowering until the final landing took almost four hours. A lot of people worked the problem.

And the aircraft and dependents flew back to Guam three days later. And I flew several hundred hours on that aircraft a decade later.

.
Not all who wander are lost.
 
roseflyer
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RE: Procedure In A Landing Gear Failure

Mon Feb 02, 2015 6:23 pm

If the landing gear do not extend, there is a manual extension option to the pilots. For manual extension sometimes this is a button or lever which sends an electronic signal for the gear uplocks to release the gear or sometimes it is a manual cable that rotate the uplocks. When doing a manual extension, the landing gear free falls.

If one or more gear are not deployed, the procedure calls for no speed brakes, no autobrakes, no reverse thrust, engine bleed off, and for the fuel pumps to be turned off just before flare. Other than maximum flaps, the actual flare and landing aren't different.
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