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Keepitup
11th Feb 2014, 14:44
In need of a little help.

Very simple question - Use of Ty-Wraps and which type.

The engineers have it in their heads but are not sure, the use of Ty-wraps with the metal barbs on electrical wiring has been stopped, due to the potential hazard that the metal barb could cause arcing/fire, if the ty-wrap fails.

Therefore only ALL plastic ty-wraps should be used ?

Does anyone know if this is true and if so, where does it state it ????

Keepitup
EASA Land

Vendee
11th Feb 2014, 18:07
I haven't seen a metal barbed ty-wrap used for quite a few years across different aircraft type. I don't know if this is mandated anywhere.

Lokon
11th Feb 2014, 18:27
Read the IPC it will give you the correct one to use at the specific location or is this a trick question to catch the engineers/company out.

FSXPilot
11th Feb 2014, 19:09
As has already said it depends what is written in the IPC. The ones that I'm aware of that are of the MS-xxxx type all have a metal insert. None of the aircraft we work on have all plastic Ty-raps. Read and follow your aircraft's IPC.

Phalconphixer
11th Feb 2014, 19:48
The UK company I worked for for 15 years were engaged in deep-strip modifications to bring former N reg Falcons onto the UK reg., invariably involving partial or complete rewiring of Avionics systems and more latterly complete glass cockpit installations. At no time were metal barbed ty-wraps used and none were found in the original wiring installed by Dassault, FalconJet or Little Rock Airmotive. Don't think I've ever encountered them in any aircraft installation.

Keepitup
12th Feb 2014, 10:50
LOKON,

Not a trick question !!, it was a question asked by the engineers.

We do follow the IPC as required, but then again you normally have commercial stock of ty-wraps as well, the question was only, can you fit Ty-wraps with the metal barbs or not ?

Keepitup

NB. I have been told an MD11 had an avionics fire and the cause was put down to the failing of a ty-wrap with the metal barb and the barb caused arcing which resulted in a fire.

Phalconphixer
12th Feb 2014, 11:07
keepitup...

Haven't come across any instances of barbed tywraps causing a fire but the potential is there. Your 'incident' could however have been brought about by a related problem... there are many reported incidents of arcing and tracking caused by insulation failures and breaddown of Kapton wiring which I believe was used extensively by both M-D and Boeing.

pp