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HAWK21M
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Tcas & ATC Transponder U/s Despatch

Tue Dec 14, 2004 3:11 pm

What are the conditions under which an Aircraft can be despatched under MEL with unserviceable TCAS system.
Secondly what about if both ATC Transponders are unserviceable,under what conditions can an Aircraft be despatched.
ie the Aircraft will not be squaking & will not show up on Radar.Is constant reporting of Altitude a condition for despatch.
Is Ferry an only option.
Anyone with Experience.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
PhilSquares
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RE: Tcas & ATC Transponder U/s Despatch

Tue Dec 14, 2004 3:30 pm

It all depends.

First of all, I don't have the MEL in front of me, but if I remember correctly, if you're flying into RVSM airspace, you have to have a transponder with altitude capability. There is no relief in the MEL.

If TCAS is inop, I can't remember at all. I think again, depending on the airspace, you might be stuck, especially if it's RVSM.

Again, there is no relief for a ferry flight.

I will say, it's extremely rare of one transponder to fail, let alone both.
Fly fast, live slow
 
LAXintl
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RE: Tcas & ATC Transponder U/s Despatch

Tue Dec 14, 2004 4:42 pm

At a major US airline, one can dispatch with inop TCAS as long as interestingly one does not overfly the Indian continent (remember Saudia B747 inflight accident). The system needs to be made servicable within 10 days.

One cannot dispatch with both ATC transponders inop.

From the desert to the sea, to all of Southern California
 
A320-Tech
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RE: Tcas & ATC Transponder U/s Dispatch

Tue Dec 14, 2004 6:32 pm

MEL,

Dispatch is possible with BOTH TXPDRs inoperative and is considered a CAT - D MEL (120 Days). The conditions that the FAA has placed on US operators include:
- ATC with jurisdiction over airspace to be utilized grants approval BEFORE departure
- Operations in RVSM airspace is prohibited
- TCAS will also be considered to be inoperative in this case.

You can read all the FAA MMELs at http://www.opspecs.com/AFSDATA/MMELs/Final/transport/

R'gds,

A320-Tech
 
PhilSquares
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RE: Tcas & ATC Transponder U/s Despatch

Tue Dec 14, 2004 7:06 pm

A320-Tech..Just a note of caution. Your reference is the MMEL. Most airlines have an MEL that is more stringent than the MMEL. I would be very surprised if any airline in the US has the ability to dispatch with a transponder due to their own more restrictive MEL.

I say this because, there is no guarantee the ARTCC(s) that will utilized will grant the exemption and based on that the airlines wouldn't really be able to count on getting it. Makes a/c routing a little difficult.

I did a little research and in our (SQ) MEL on the 744, you can't be dispatched with both XPDRS inop, no can you be dispatched if the TCAS is inop.
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HAWK21M
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RE: Tcas & ATC Transponder U/s Despatch

Tue Dec 14, 2004 7:25 pm

ATC with jurisdiction over airspace to be utilized grants approval BEFORE departure
Are you saying ATC will grant approval not FAA.

Also U/s Transponder would require verbal reporting of Altitude at frequent intervals.If flight is permitted.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
crjdispatchkid
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RE: Tcas & ATC Transponder U/s Despatch

Wed Dec 15, 2004 2:01 am

I know with our CRJ's you can be dispatched with both transponders INOP, but you need to get pre-flight approval from ATC centers. So usually you hope it's on a short flight so you do't have to call too many traffic management units!
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air2gxs
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RE: Tcas & ATC Transponder U/s Despatch

Wed Dec 15, 2004 4:25 am

If I remember correctly, our MEL(s) allow dispatch with a dual transponder failure as long as all the ATC centers enroute are notified and approve it. I can't remeber if its a CAT A (time limited, sometimes hours) or CAT C (10 day). As a practical consideration, in a post 9/11 world, the operator would get the system fixed as fast as possible as the centers may deny permission anywhere along the route.
 
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HAWK21M
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RE: Tcas & ATC Transponder U/s Despatch

Fri Dec 17, 2004 5:31 pm

Referring to the Master MEL it does permit despatch with Both Transpondersu/s provided ATC of the Area covered is aware.But our MEL only permits One Transponder u/s.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
air2gxs
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RE: Tcas & ATC Transponder U/s Despatch

Fri Dec 17, 2004 11:15 pm

The MMEL is what the FAA and manufacturer have come up with to permit safe flight. The operator can be as restrictive as it wants to be in configuring its MEL, the operator just can't be more liberal than the MMEL without a whole lot of permission.
 
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HAWK21M
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RE: Tcas & ATC Transponder U/s Despatch

Sat Dec 18, 2004 1:58 pm

Can a MEL be relaxed further as long as its not less restrictive than the MMEL.
What would be the procedure.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
PhilSquares
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RE: Tcas & ATC Transponder U/s Despatch

Sat Dec 18, 2004 6:38 pm

I am just starting a 7 day trip, the first day is now done. I had a chance to review our MEL on the issue of transponders and TCAS.

Our MEL does not allow dispatch with both transponders inop. Simply stated, you just can't go.

TCAS can be inop provided you are not flying into RVSM airspace. Practical application: You can't go.

As far as the MEL being relaxed, that process is not a quick process. Initially, the courtry's regulatory body, ie., FAA/CAA approves the MEL. To have something "relaxed" you have to now re-write the MEL and submit it to the CAA/FAA. As with any regulatory body, the wheels don't move quick.
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air2gxs
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RE: Tcas & ATC Transponder U/s Despatch

Sun Dec 19, 2004 10:53 am

ONce an operator's MEL is approved any changes, and I mean any changes (typos, format, structure, wording, restrictions) must be approved by the FAA. Theonly time I've seen the process move at anything resembling a fast speed was an AD driven change to the B757 center fuel pump system. The AD was released and we were restricted almost immediately.

To change an MEL, we submit a request to fligt ops (it is a flight document) and justification. They get together with us, review it and make a decision as to whether to resent it to the FAA. The FAA then reviews the change, the justification and the MMEL. Then the FAA renders its decision.
 
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HAWK21M
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RE: Tcas & ATC Transponder U/s Despatch

Sun Dec 19, 2004 3:00 pm

The AD case was an added restriction hence it moved fast.In cases where relaxation to the MEL is required,that takes a long time.
But can that be considered as long as its not less restrictive than the MMEL.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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