bio15
Posts: 1048
Joined: Fri Mar 23, 2001 8:10 am

RAT Positioning On A/c

Thu Jan 16, 2003 7:04 am

I just learned the RAT on the DC-10 (and I assume on the MD-11) is located near the front of the fuselage, just as in some business jets. Considering aircraft manufacturers are always taking into account a lot of safety issues with the aircraft integrity, isn't it a risk to put the RAT foreward considering if it breaks the engines might ingest debris? What sort of requirements are needed for a RAT being certified? Am I being too paranoid?  Smile

-Alfredo
 
Staffan
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RE: RAT Positioning On A/c

Thu Jan 16, 2003 7:07 am

Thing is, the RAT is usually not used until the engines are actually broken..

Staffan
 
bio15
Posts: 1048
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RE: RAT Positioning On A/c

Thu Jan 16, 2003 7:59 am

Well, that's very logical and evident. Don't know how I missed that point!! Thanks
 
LMP737
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RE: RAT Positioning On A/c

Thu Jan 16, 2003 10:12 am

There are several things to remember about the placement of the RAT on the DC-10 and MD-11. If the RAT does come apart for some reason chances are the debris will not be ingested by the #1 and #3 engine. Besides if you deploy your RAT and it fails you have some serious problems other than worrying whether the pieces damage an engine. Since there are fewer and fewer DC-10's and MD-11's flying passengers the chances of you actually being on one when they have to deploy the RAT are slim.
Never take financial advice from co-workers.
 
brons2
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RE: Etops Regs Could Be Expanded To 3- & 4-eng

Thu Jan 16, 2003 3:11 pm

Pardon my ignorance, but what is the "RAT"?
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dash8tech
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Joined: Mon Jul 05, 1999 8:40 pm

RE: RAT Positioning On A/c

Thu Jan 16, 2003 3:16 pm

The RAT is the "Ram Air Turbine", sometimes also called the ADG or "Air Driven Generator". Used to supply back up electrical and hydraulic power in the event of a serious failiure of the afformentioned.

As far as my experience goes in aircraft MTX, the RAT as it was called in the Navy on the A-6 Intruder was mounted on the left wing. The ADG on the CRJ is mounted on the right side of the nose just aft of the radome.

But like many have mentioned, if you need to use it the least of your worries would be it fodding an engine (if you have one running!) if it too came apart.

Cheers!
 
covert
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RE: RAT Positioning On A/c

Fri Jan 17, 2003 1:43 am

Whew, we sure are giving the RAT its fair share of attention this month, are we not?
none
 
Rick767
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RE: RAT Positioning On A/c

Fri Jan 17, 2003 1:53 am

"Used to supply back up electrical and hydraulic power"

Remember the RAT (or ADG) does not always provide both backup electrical and hydraulic power. On the 767, for example, it only provides hydraulic power to the flight controls portion of the Centre Hydraulic System (which theoretically gives us enough juice to still be able to control the aircraft).
I used to love the smell of Jet-A in the morning...
 
dash8tech
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RE: RAT Positioning On A/c

Fri Jan 17, 2003 3:47 pm

Good point Rick767 in fact thinking back I believe in the A-6 Intruder the RAT only provided emergency electrical power, no hydraulics at all.

Cheers!
 
FDXmech
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RE: RAT Positioning On A/c

Fri Jan 17, 2003 4:20 pm

Basically, on the DC10/MD11 the ADG provides A/C power to either the right emergency bus system or an auxiliary hydraulic pump (#3 system).

I've never actually seen an instance where the ADG was deployed by the flight crew.
You're only as good as your last departure.
 
FDXmech
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RE: RAT Positioning On A/c

Fri Jan 17, 2003 4:31 pm

Here's a good photo of the ADG's location (on the DC10). It's the red panel just to the right of the right nose gear door.

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Photo © Jason Knutson

You're only as good as your last departure.
 
DL_Mech
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RE: RAT Positioning On A/c

Fri Jan 17, 2003 7:40 pm

I would assume that RAT (ADG) positioning has a lot to do with cable run lengths or hydraulic plumbing complexities.

The DC-10/MD-11 ADG is located near the cockpit, so that the mechanical deploy linkage from the cockpit is kept as simple as possible. It is also near the Avionics Compartment which houses some of the components that power the Aux Hyd Pump -1.

The L-1011 has a hydraulic-generating RAT that is located just forward of the main wheel wells. It was deployed by an explosive squib (no mechanical cables) and is close to the Hydraulic Service Center, minimizing the hydraulic plumbing needed from the reservoirs.

The 757/767's have a similar hydraulic-generating setup near the main wheel wells.

The 777 has both Electrical power and Hydraulic power generation from its RAT.
This plane is built to withstand anything... except a bad pilot.
 
Airbus_A340
Posts: 1439
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RE: RAT Positioning On A/c

Fri Jan 17, 2003 7:59 pm

Just a little joke here from a friend from Lufthansa Technik.
The RAT is sometimes nicknamed the "Ramp Agent Terminator" because of the speed it drops down from the fuselage, lol  Smile

Airbus_A340
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muddydawg
Posts: 56
Joined: Fri Jan 17, 2003 10:17 am

RE: RAT Positioning On A/c

Sat Jan 18, 2003 5:50 am

When I was stationed at Travis on KC-10's every time they came home from "C Check" they used to deploy the RAT. After they did the FMS 800 mods the first two that came home from "C Check" that deployed the RAT caught the #1 Aux pump on fire. I never did find out why. Does anybody know if this happened much on the civilian side of the -30 series 10's.

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