More....
Maintenance say that the correct TR gearbox oil level is when the oil is halfway filling the sight glass with the aircraft in the 'rigged' position, ie. when it has the front of the skids raised to such a height that a spirit level placed by the mixture control (pointing fore/aft) shows the aircraft is level over the ground, not relying on the skids.
The amount that the skids must be lifted (and the tail moved down) would depend on the individuality of R22's, something which is due to many things. (not least that they are all hand built and vary from new) A major factor is how the undercarriage may have changed from its original shape due to engine off landings and so on. It is one of the reasons the 'stinger' has to be over 36" from level ground on an R22B.
The tail is higher with the skids fully aground than it would be with the Heli. in the rigged position. Does this suggest that the Gbox oil level cannot be properly checked unless the tail is lowered?
I did give some thought to another aspect. If moving the Heli out of a hangar (or anywhere) for the first flight of the day you'd be using the wheels and lowering the tail to push and steer.....So, the sight glass should show its level then and no separate lowering of the tail is required......Until you have to do the aft TR flex coupling check!
This has been an interesting exercise in understanding the POH. It seems that even these can have anomalies and it looks as though at least two have shown up here. The POH should tell you how to check the oil level, from which position and how to get it to the required position, not just say 'Full and no leaks'.
I'm sure that more info will come to light yet.
....And it HAS....
Rotorhead 4 is correct, POH 8.8 says this;
'If the sight gauge of the Helicopter does not fill when the tail of the Helicopter is pulled all the way down, oil muct be added'
and it goes on to describe how oil is added... (Although I'm sure you'd have to be a licenced engineer to do it).
So, two pieces of info suggect that you should lower the tail and one fails to tell you to do it in the pre-flight. Confusing?
Well it could be!
Anyway, I'm sure that some find this interesting and others find it all rather boring but there was a point to it -
If a habit of incorrectly checking TR Gbox oil had circulated, one which did not appear in the POH then it might just have been significant. Would any of us advocate tilting the engine to make the dipstick read apparently more sump oil content?
Finally for Muffin... Today I had a description of a 'crease' being put in the front lower part of the tailcone by someone who tried to do the check whilst his passenger was in the cockpit....Repair bill
$15,000 NZ.
The advice that tail lowering can be a good way to check that your skids are not stuck to the ground was included in a previous post and I just happen to know the guy who gave it..!
Thanks all.