Originally Posted by
JamesT73J
I think it might be the same operator, perhaps a sister aircraft.
No. Blade is a different operator than the accident aircraft.
Originally Posted by
helispotter
First of all, is it fair to assume the two broken tubes emerging from within the tail boom are the tail rotor pitch control and the elevator control links?
Yes. The larger diameter one is to the elevator.
Will start by including a layout drawing of a 206L-3 from a Bell brochure (the L-3 is presumably mostly similar to the L-4):
Yes. But in general the L-4 has a different MR/TR drive system and higher gross weight.
Next, a pair of views near the fractured tail boom but also looking forward to what I understand from Kulwin Park (#139) is the Oil Cooler Fan (dark green). A spline end of a portion of tail rotor drive shaft is visible where marked by arrows, with support bearing still intact at that location:
Yes. But its technically called the oil cooler blower. The splines are part of the blower which is also called the #2 TR shaft.
a seemingly fractured section of tail rotor drive shaft further forward below the engine (see again arrow):
That is the #1 TR driveshaft and it appears to be sheared near the middle of the shaft. Given the engine was torn loose seems plausible it would break there since the blower is still intact which would be where that #1 shaft connected to.
It isn't obvious to me the fracture of the tail boom is due to a drive shaft flailing about given the bearing seat near that fracture isn't massively distorted.
Except if the aft end of the #4 TR shaft came lose or failed it would have hit the t/boom in the area of where the t/boom tore off. Plus the remains of the #4 shaft hangar bearing can still be seen in its deformed mount on the forward edge of the installed t/boom portion.
Drive shaft may have been pulled apart at spline aft of oil cooler fan when the tail boom folded as seen in video?
The #3 TR shaft only slides onto the aft blower splines as does the #1 TR shaft at the fwd blower splines. The aft end of the #3 shaft would bolt to the #4 shaft at the distorted hangar bearing mount.
I think a good question would be what caused the #4 hangar bearing to fail and where are the #3, #4, #5 TR shafts?