hoistop
8th Apr 2015, 08:16
I am looking for info regarding configuration of Transmission oil filter housing on A-109 Power.
Namelly, original design (same as old A-109 A-C) has (quite large) oil filter bowl, containing filter element, which is attached to filter housing (magnesium) with single long, thin bolt, that goes straight thru bowl and filter cartridge itself, screwed into (magnesium) filter housing and its prescribed torque is really low - almost hand tight.
Sealing accomplished thru large O-ring on bowl and small sealing washer under long bolt head.
For my taste, it is an unusual, old fashioned design and I really don`t like it (thinking of Cougar Helicopters S-92 disaster).
I noticed that later serial No`s have different-more typical design where filter bowl is attached to housing via four studs / nuts, as most filter housings are installed (like PT6...)
It is interesting to note that AW never published an SB to optionally replace old design with new one, they only made that option available thru IPC with notice that tells you that old design is superseded by new design (but I don`t see how in real world you would come to a need to replace entire oil filter housing and thus change it for newer design, as old one is not procurable anymore)
My question is:
has anyone heard of the reasons of this design change? Any known problems-incidents on this item (oil leaks...)
Any info very much appreciated.
Regards,
hoistop
Namelly, original design (same as old A-109 A-C) has (quite large) oil filter bowl, containing filter element, which is attached to filter housing (magnesium) with single long, thin bolt, that goes straight thru bowl and filter cartridge itself, screwed into (magnesium) filter housing and its prescribed torque is really low - almost hand tight.
Sealing accomplished thru large O-ring on bowl and small sealing washer under long bolt head.
For my taste, it is an unusual, old fashioned design and I really don`t like it (thinking of Cougar Helicopters S-92 disaster).
I noticed that later serial No`s have different-more typical design where filter bowl is attached to housing via four studs / nuts, as most filter housings are installed (like PT6...)
It is interesting to note that AW never published an SB to optionally replace old design with new one, they only made that option available thru IPC with notice that tells you that old design is superseded by new design (but I don`t see how in real world you would come to a need to replace entire oil filter housing and thus change it for newer design, as old one is not procurable anymore)
My question is:
has anyone heard of the reasons of this design change? Any known problems-incidents on this item (oil leaks...)
Any info very much appreciated.
Regards,
hoistop