Lufthansa has already tried to respond to a person asking a similar question on their Facebook page:
Dear Lufthansa My sister is flying with Lufthansa on Thursday, from
Johannesburg to Zagreb. She will be flying with her musical
instrument, the violin. Please let me know how we can get permission
for her to take her violin on board as hand luggage, as she cannot let
it out of her sight, even for a second.
In the past, it was no problem to take it on board, but lately I know
of some challenges. The violin in its case is les than 2 kg.
Dear Katrien, if your sister is travelling in Economy Class, then she
is allowed to bring on piece of hand luggage into the cabin. The
maximum weight is 8 kg and the maximum dimensions are 55 cm x 40 cm x
23 cm. If these restrictions are not exceeded than it shouldn’t be a
problem to bring her violin into the cabin. More information about
hand luggage can be found here: http://f.lh.com/eFkB
Thank you. The dimensions are 15 x 25 x 85 though.
Dear Katrien, as one of the given dimensions is exceeded I can't
guarantee from my side that your sister will be allowed to bring her
violin into the cabin. This decision needs to be made by my colleagues
at the airport.
So it's going to depend on what size your case is, I suspect, and the feelings of staff at the airport, on the day, as to whether it's allowed as carry-on.
As for checking it, Lufthansa, like other airlines does their utmost to ensure it's safe. However, airports employ non-airline staff to handle luggage, so sometimes it's out of Lufthansa's control.
In the event it IS damaged (unlikely but possible), their page on how to handle this suggests:
- Report the damage immediately at the airport
- Make a subsequent complaint about damage
- and that they'll compensate you according to their liability - roughly 1200 Euros, which can fluctuate.
So ideally you'll want good travel insurance, with your instrument itemised on that policy beforehand, with photos and details to prove it before you depart.