I'm going to northern Cyprus with Turkish airlines and want to take a 40 inch smart TV that I bought here in the UK with me. Can't find out if this is possible or how much it would cost as it weighs 14kg and as it is fragile how it should be packed if going in the hold. This would be in addition to my 23 kg luggage. Reason is TVs in northern Cyprus are very expensive compared to UK
Typically 62 linear inches is the allowance for a checked in bag and there is no way the box of 40" HDTV is under that. For example http://www.brandsmartusa.com/Samsung/184264/40+Class+Smart+1080P+LED+HDTV+With+Wi+Fi.htm this 40" HDTV is in a 90 linear inch box and that's typical. You will likely be charged an oversize baggage fee -- typically $100-$200. Possibly double for two legs. If oversize baggage fee would be the only problem you could call Turkish and find it out. But that's the smaller problem.
Then comes the problem of fragility. Typically these things are protected by having shaped rigid foam on their corners (or perhaps the edges) but I have never seen any of these TV boxes containing a huge foam rectangle covering the whole entire screen. And airlines will not take responsibility for fragile items as checked luggage. So says Turkish policy
The passenger should not include in his or her baggage: [...] Items which in the opinion of Carrier are unsuitable for carriage by reason of their weight, size or character, such as fragile or perishable items;
Even if they would accept it they'd make you sign a waiver. I often fly with a 22" LCD monitor in my suitcase (ok, not on Turkish but in this all airlines are the same) and I have signed many of those before getting my Fragile sticker (which is of very dubious value, I know). But my monitor is in a Geargrip LCD harness which well protects the front of the monitor and then it is lying on a normal sized pillow to protect the back and then this whole shebang is packed in a Samsonite Firelite hardshell. This really does protect the monitor but then again it's only 22" and not 40".
My advice: use appropriate cargo service. Turkish Airlines has http://www.turkishcargo.com.tr/en one.