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Recently noticed on preflights that tail rotor gearbox oil driptray has occasional black staining in it.Has anyone experienced this ?

HI i am not sure on what your calling drip tray.If you mean skid plate below gear box.The gear box sounds like its coming loose.and if it is black oil its on the box where the long shaft bolts to gear box most likely.. its called making mud.. aluminum when it comes loose it turns the oil black so definitely something is loose ... needs checked before flight and find problem.and I have seen these leak before.run it long enough there could be big problems.like break tail rotor shaft. and.. could be other problems to why its leaking.. bushing in lower box wore out where an 4 bolt holds box to pylon...be safe lets us no what you find out.....tom

Thanks for the response,I mean by drip tray,the plastic tray on the floor of the Hangar to catch the drips from the tail rotor gearbox that you always get.Usually the colour of the oil that you top it up with but recently its had the odd shade of light grey,or patches of black.I suppose it sounds like gear or bearings making metal doesnt it?

HI again .it to me sounds like something is loose.when you fly for a period of time does one of your feet seems to go to sleep. if that happens then you got a vibration and that will make things come loose back there.and there should not be any oil leaks back there at all. maybe a little on vertical shaft just a little spray from vent hole.hope this helps....drain out gear box oil in a clear glass see if there is any gear or bearing fuzz in it.that would be my start.but sounds like it just needs sealed back up.but usually something caused this..so you have to track it down.to weather it was bearing ?tail blades out of track? or wrong sealant used or just wasn't torqued properly something like that........tom

Thanks for reply funny you should say about my foot going to sleep.I always assumed it was because my ankle was held on with screws and plates.When I say drips I am only talking the usual post flight expansion drips on the rear vertical shaft that drip from the point on the rear tail rotor guard.I think I will get my Maintainance place to drain the tail down next time and have a look.By the way when you say vibration Im assuning you mean from an out of balance tail rotor.

HI yes out of balance on tail rotor.and this leads to could be tracking? one blade to heavy? bearings in blade spar or rod end bearings ? hub spindle bearings ? could be brindle.but yes a old helicopter pilot and mechanic told me a long time ago if your foot falls a sleep or goes numb its a high speed out of balance tail rotor.check it with a chadwick balance.you'll be surprised or do the method in brantly manual i think its 1/ 32 on a caliper of movement measured on tail guard.A brantly should be very smooth on main rotor and tail .if all is right.there is so much to no abought a helicopter to be safe. remember brantly has its Owen rotor system that no other helicopter has this is why i tell pilot's..owners to find out as much you can from the old mechanics that worked on these brantlys the manual only gives a basic start.this is why i like brantlys there a breed of its own.but a very good one.... hope this helps...be safe and have fun....tom