System deactivation procedure

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System deactivation procedure

Postby danil » 06 Jan 2008, 02:26

Hi,

I have some hard talks with our tech dep regarding the deactivation of different system on the plane. The question is how your company deactivate a sys which it doesn't need (the system works ok)? For instance my company just pull the CB, guard it and label it "INOP" but they do not make any teh log entry. I personally think that ,apart from the procedure described above, there should be an entry into the teh log. Any comment?
The issue is actually the deactivation of the airstair of a 737. The airstair works just OK but the company wants not to use it. The technicians just pulled the cb's and labeled them, along with all the switches associated with it, inop having no log entry. And the airstair is not the only one system. We got the in-flight entertainment in the same situation.
I have checked the AMM but I fond no reference to this procedure. I believe this procedure should be in MOE but it is not there. Anyway, I personally think that it should be some kind of entry into the teh log saying the sys is deactivated and specifying which CB's are pulled along with required labeling.
I have recently been told that there should be a technical procedure controlled by quality department describing the deactivation process. A deactivation being a totally different thing than a defect. In general a deactivation can affect different system and/or performance. Can you check with your tech dep about such a procedure?

danil
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Re: System deactivation procedure

Postby sjap » 06 Jan 2008, 04:57

Hi Danil,

I personally think you are right.
Deactivated systems should be noted in the tech log in any way. We use the ABC (Aircraft Briefing Card), which describes the deactivated systems or other flight operational issues which the pilot must know to operate the aircraft.
The ABC is in front of the techlog, together with the deferred defects list, release documents and so on.
The ABC is updated as soon as there is a change in status of the affected airplane.

The deactivation procedures can be found in the AMM or in the MEL, and the systems can be deactivated as if they where unserviceable. The MEL maintenance (M) items or operational (O) items are then covered too.
See for the master MEL:
http://www.opspecs.com/AFSDATA/MMELs/Final/transport/

Fleetwide deactivated systems must be known by the flight department and communicated to the flight crew. This can be done by the engineering department in coop with your flight operation department or similar department. this is also true for different aircraft mod status and so on.
I hope this answer helps you a bit.
Best regards
sjap
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Re: System deactivation procedure

Postby danil » 06 Jan 2008, 13:11

sjap,

Thanks a lot. It clarifies a lot. Actually we have in the ATL the "Briefing Card" system but apparently the Tech department just do not know that they have to put the info there. Also, we definitely have a big communication problem between flight ops management and Tech management. Thanks a lot again.

PS. A short question. Is there any rule or a standard regarding the collar s to guard the CB, open? I have seen some collars specially designed having an opening for easy removal and re-use. Our technicians just use a white strip designed for sealing (I do not how to correctly describe this thing) which tighten and blocks the CB. To remove such a thing you need a clipper because it is really difficult to remove it.

Rgds,

Danil
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Re: System deactivation procedure

Postby sjap » 06 Jan 2008, 15:14

Hello Danil,

Yes there are officially red colored CB clips. They go over the extended CB. They are indeed removable.
I think it is p/n G57NB5
We use also green ones (for deactivation of dangerous systems during maintenance).

Image

Hope this helps you a bit
best regards
sjap
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Re: System deactivation procedure

Postby Stan » 10 Jan 2008, 09:52

Gday Sjap

those clips , do they restrict u to close c/b or they are just for marking??

thanks Stan
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Re: System deactivation procedure

Postby sjap » 10 Jan 2008, 10:44

Hi Stan,

The red ones are to prevent the cb from closing. You have to pull the cb and then install the collar around it.
The green ones are to mark them , and you can normally open / close this cb. They are a bit smaller of course.

I ve seen some companies who use a tyrap around the pulled cb, just as Danil wrote. But the problem is that a tyrap is :
-not removable without a tool (you must cut it)
-its white colored, so the difference with a popped cb is hardly visible. This can be dangerous, because a pilot looks over his shoulder and sees a white band, thinking the cb is popped, while it is clipped with a white tyrap (or the cb is popped indeed...)

Best regards
sjap
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Re: System deactivation procedure

Postby Pete » 10 Jan 2008, 11:16

HI SJAP,I DONT AGREE WITH YOU THAT TY WRAP AROUND A PULLED CB IS DANGEROUS BECAUS IF YOUR PILOT THINKS ITS POPPED HE TRIES TO RESET IT,BUT AS WE KNOW ITS BLOCKED AND BY THE WAY IF YOU PULL A CB ,YOU MUST MAKE AN ENTRY IN THE LOG BOOK, SO THE CREW KNEW THIS BEFORE THE FLIGHT.AND TO REMOVE IT YOU CUT IT WITH A SIDE CUTTER,I ASSUME THATS A STANDARD TO HAVE IN YOUR TOOL BOX.
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Re: System deactivation procedure

Postby sjap » 10 Jan 2008, 11:27

Pete wrote:HI SJAP,I DONT AGREE WITH YOU THAT TY WRAP AROUND A PULLED CB IS DANGEROUS BECAUS IF YOUR PILOT THINKS ITS POPPED HE TRIES TO RESET IT,BUT AS WE KNOW ITS BLOCKED AND BY THE WAY IF YOU PULL A CB ,YOU MUST MAKE AN ENTRY IN THE LOG BOOK, SO THE CREW KNEW THIS BEFORE THE FLIGHT.AND TO REMOVE IT YOU CUT IT WITH A SIDE CUTTER,I ASSUME THATS A STANDARD TO HAVE IN YOUR TOOL BOX.


Thats exactly what Danil states in his message: They make no entry in their techlog. so their pilots dont know.
I still think its not a good thing if you can mistake a popped cb by a deactivated (tyrapped) cb. It makes the cb panel confusing leading to errors.
It must be clearly and quickly visible what the status is of the cb panel.

Of course we have cutters. But not in my pocket when i enter the cockpit. I dont carry all tools in my pockets all the time. Thats another discussion.
sjap
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Re: System deactivation procedure

Postby lookilook » 18 Jan 2008, 11:11

hi,

in my company we have internal procedures for deactivation of a non defective system,like airstair lets say,relevant cb is pulled and collar is placed for protection and then we unplug all connectors and secured them with tierabs and covered them.on the airstair panel we placed a sticker"inoperative see tech log" and in the tech log an entry is made on that day and also an LSR(line station requirement)for periodic check
of plugs and cb to be carried out every weekly check.

a tierab around a cb is dangerous especially when inexperienced mechanic is called to cut it since usually there is not enough space to place your cutter you force it to fit in and then the cb breaks...it happened once but no more since the collar policy.
WE KEEP 'EM UP!!
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Re: System deactivation procedure

Postby troubleshooter » 20 Jan 2008, 14:11

Deactivated systems should be noted in the tech log in any way. We use the ABC (Aircraft Briefing Card), which describes the deactivated systems or other flight operational issues which the pilot must know to operate the aircraft.
The ABC is in front of the techlog, together with the deferred defects list, release documents and so on.
The ABC is updated as soon as there is a change in status of the affected airplane.


We do it exactly like this in our company.
This job sucks!!! I love this job!!!
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