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ojjunior
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A MD-11 w/out main center landing gear??

Mon May 15, 2017 2:32 pm

Browsing a.net I found this lovely pic taken in 2005 in AMS, however AFAIK there's no MD-11 w/out center landing gear but couldn't find any info.
Image
Any thoughts?
Tks
 
kalvado
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Re: A MD-11 w/out main center landing gear??

Mon May 15, 2017 2:38 pm

Here is another pic of same jet, PP-VQJ, with center gear: http://www.airliners.net/photo/Varig/Mc ... ER/1063275
As far as I remember, there was a discussion about center gear on at least some types being deployed only if above certain weight. That would be my bet.
 
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Starlionblue
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Re: A MD-11 w/out main center landing gear??

Mon May 15, 2017 3:09 pm

AFAIK the MD-11 the center gear is a MEL item. If it isn't working, you read the book and figure out what you need to dispatch with it retracted.

It's not trivial through. One of the comments in a past thread was "alert the crew to the coming weight and balance nightmare"... :D
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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zeke
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Re: A MD-11 w/out main center landing gear??

Mon May 15, 2017 3:16 pm

Can do the same with the A340 as well.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
kalvado
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Re: A MD-11 w/out main center landing gear??

Mon May 15, 2017 4:02 pm

Starlionblue wrote:
AFAIK the MD-11 the center gear is a MEL item. If it isn't working, you read the book and figure out what you need to dispatch with it retracted.

It's not trivial through. One of the comments in a past thread was "alert the crew to the coming weight and balance nightmare"... :D

Wasn't that for the situation when the gear had to be deployed, as plane would be close to MTOW?
 
kalvado
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Re: A MD-11 w/out main center landing gear??

Mon May 15, 2017 4:37 pm

kalvado wrote:
Starlionblue wrote:
AFAIK the MD-11 the center gear is a MEL item. If it isn't working, you read the book and figure out what you need to dispatch with it retracted.

It's not trivial through. One of the comments in a past thread was "alert the crew to the coming weight and balance nightmare"... :D

Wasn't that for the situation when the gear had to be deployed, as plane would be close to MTOW?

Nope, my bad. Here is that ancient thread: viewtopic.php?t=742615
 
BravoOne
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Re: A MD-11 w/out main center landing gear??

Mon May 15, 2017 7:12 pm

I seem to recall that if you were at 430K for T.O. you could operate. You could not retract the Center gear while on the ground so you had to plan ahead.
 
RetiredWeasel
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Re: A MD-11 w/out main center landing gear??

Mon May 15, 2017 7:51 pm

BravoOne wrote:
I seem to recall that if you were at 430K for T.O. you could operate. You could not retract the Center gear while on the ground so you had to plan ahead.


You would be close according this World MD-11 Flash Quiz that I stumbled on. Go to the bottom and see the limitations:

https://quizlet.com/2624065/world-md-11 ... ash-cards/
 
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Horstroad
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Re: A MD-11 w/out main center landing gear??

Tue May 16, 2017 12:16 am

The MEL allows for a dispatch of 1 inoperative brake. (number installed 10, number required 9). So if you had two brakes inoperative and no spare parts on hand your plane would be grounded. Similarly if you had a damaged wheel/tire assembly. You can't fly with that.
But you can put the broken parts on the CLG and and set the CLG inop according MEL.
By doing so you reduce the MTOW to 201849kg which means you might need to unload some cargo, but at least you get the plane back home.
 
FlyHossD
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Re: A MD-11 w/out main center landing gear??

Tue May 16, 2017 3:52 am

Horstroad wrote:
The MEL allows for a dispatch of 1 inoperative brake. (number installed 10, number required 9). So if you had two brakes inoperative and no spare parts on hand your plane would be grounded. Similarly if you had a damaged wheel/tire assembly. You can't fly with that.
But you can put the broken parts on the CLG and and set the CLG inop according MEL.
By doing so you reduce the MTOW to 201849kg which means you might need to unload some cargo, but at least you get the plane back home.


As I recall, the D.C.-10-30 could be dispatched without the center main gear , but it was about a 100,000 pound weight hit.
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AA737-823
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Re: A MD-11 w/out main center landing gear??

Tue May 16, 2017 4:56 am

FlyHossD wrote:
Horstroad wrote:
The MEL allows for a dispatch of 1 inoperative brake. (number installed 10, number required 9). So if you had two brakes inoperative and no spare parts on hand your plane would be grounded. Similarly if you had a damaged wheel/tire assembly. You can't fly with that.
But you can put the broken parts on the CLG and and set the CLG inop according MEL.
By doing so you reduce the MTOW to 201849kg which means you might need to unload some cargo, but at least you get the plane back home.


As I recall, the D.C.-10-30 could be dispatched without the center main gear , but it was about a 100,000 pound weight hit.


Yes, and I recall that the Japanese would convert DC-10 aircraft (I believe the -40, which is just a -30 with Pratt engines, more or less) back and forth from domestic to international configs as the market required, by removing and reinstalling the center gear.
Not something you'd do on a gate turn! But doable, none the less.
 
BravoOne
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Re: A MD-11 w/out main center landing gear??

Tue May 16, 2017 9:04 am

430K is the max weight of the DC10-10 and of course it does not have the CLG. I recall the tower at SFO asking a National crew on a five final if they could leave the CLG retracted per a request from National Ops. hey replied it was to late ate they were already configured for landing. I think that was the 1st time I became aware of this capability. Later flew bot the DC10--10 and occasionally the -30 , but never left the CLG in the up position. As for CLG brakes we flew the MD11's for almost a year without arming the ABS because of issues with the CLG braking systems. I do not recall the mD11 having the CLG extension as an option but I would think that the MD10 might have that capability?
 
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Horstroad
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Re: A MD-11 w/out main center landing gear??

Tue May 16, 2017 11:12 am

BravoOne wrote:
As for CLG brakes we flew the MD11's for almost a year without arming the ABS because of issues with the CLG braking systems.

I'm not too familiar with the operational procedures but I think to remember that flight crews must not use auto brakes if they are below a certain landing weight because it can rip off the center gear in the worst case
 
BravoOne
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Re: A MD-11 w/out main center landing gear??

Tue May 16, 2017 11:19 am

Apparently that's what happened during some flight tests, but I do not recall any landing weight restrictions being applied as such. Keep in mind that I have not flown the MD11 since the late nineties when I went to he 777 so my recent knowledge is minimal
 
Apprentice
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Re: A MD-11 w/out main center landing gear??

Thu May 18, 2017 7:50 pm

Hi:, from MMEL:
"Center Landing Gear"
"(M) (O) May be inoperative provided:
a) Center Landing Gear is retracted,
b) Lock links are verified to be stowed overcenter,
c) At least one Center Gear Downlock/Uplock Spring is installed,
d) At least one tire is inflated, and
e) AFM performance penalties are applied."
Rgds
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BravoOne
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Re: A MD-11 w/out main center landing gear??

Thu May 18, 2017 8:58 pm

Apprentice wrote:
Hi:, from MMEL:
"Center Landing Gear"
"(M) (O) May be inoperative provided:
a) Center Landing Gear is retracted,
b) Lock links are verified to be stowed overcenter,
c) At least one Center Gear Downlock/Uplock Spring is installed,
d) At least one tire is inflated, and
e) AFM performance penalties are applied."
Rgds


I think that what we have all been saying but thanks for the affirmation. Your material sounds like it comes from the DDG and not the MMEL?
 
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Horstroad
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Re: A MD-11 w/out main center landing gear??

Thu May 18, 2017 10:20 pm

BravoOne wrote:
Your material sounds like it comes from the DDG and not the MMEL?

This is actually a quote from the "REMARKS OR EXCEPTIONS" section of the MMEL item 32-30-2 Center Landing Gear ;)
 
Apprentice
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Re: A MD-11 w/out main center landing gear??

Fri May 19, 2017 12:21 am

Hello: My material it's a quote of faa.gov"s: http://fsims.faa.gov/PICDetail.aspx?docId=M MD-11 R12.Last Rev: Rev. 12 Date -- 08/18/2016; MMEL It. 32. 30-1 PAGE 32-1:

30-2 30-2 Center Landing Gear C 1 0 (M) (O) May be inoperative provided: a) Center Landing Gear is retracted, b) Lock links are verified to be stowed overcenter, c) At least one Center Gear Downlock/Uplock Spring is installed, d) At least one tire is inflated, and e) AFM performance penalties are applied.

More simple, for our topic: " Center Landing Gear.... May be inoperative provided: a) Center Landing Gear is retracted.... "

Rgds

RGDS
A "NO" is a positive answer., "DON'T KNOW" is not. My Tutor
 
Max Q
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Re: A MD-11 w/out main center landing gear??

Fri May 19, 2017 3:37 am

Curious why 'at least one tire is inflated' is on the MEL ?
The best contribution to safety is a competent Pilot.
 
Apprentice
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Re: A MD-11 w/out main center landing gear??

Fri May 19, 2017 6:24 am

Max, Hello, as Spaniards said: "npi" No Idea
I will not try to guess. May be some one knows?

Thanks/ Rgds
A "NO" is a positive answer., "DON'T KNOW" is not. My Tutor
 
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zeke
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Re: A MD-11 w/out main center landing gear??

Fri May 19, 2017 7:41 am

Max Q wrote:
Curious why 'at least one tire is inflated' is on the MEL ?


Some gear designs use a stop inside the gear bay on a centreline retraction type gear where the tyre makes contact to a stop, the stop is used to arrest the tyre rotation. Without a tyre installed the gear will go beyond the design retraction arc at the tyre is not there to make contact with the stop.

Don't know if that is the case here.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
Max Q
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Re: A MD-11 w/out main center landing gear??

Fri May 19, 2017 7:52 am

zeke wrote:
Max Q wrote:
Curious why 'at least one tire is inflated' is on the MEL ?


Some gear designs use a stop inside the gear bay on a centreline retraction type gear where the tyre makes contact to a stop, the stop is used to arrest the tyre rotation. Without a tyre installed the gear will go beyond the design retraction arc at the tyre is not there to make contact with the stop.

Don't know if that is the case here.



That makes complete sense whether its a tyre or a tire !
The best contribution to safety is a competent Pilot.
 
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Horstroad
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Re: A MD-11 w/out main center landing gear??

Fri May 19, 2017 2:03 pm

I could not find any information as to why one tire needs to be inflated. Neither in the MMP and the AMM nor in my training documents.
The CLG on the MD11 does not have tire stops in the wheel well. The landing gear cant't travel past its normal retracted position because the lock link goes into the overcentered position when the CLG is fully retracted, similarly to when it is extended.

Only reason I could think of was that during retraction the gear rolls forward on the tires. Even though the shock strut needs to be deflated during the process, the stresses might be too great when both tires are deflated and the gear cant properly roll forward.

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