Hydro seal retainer

In an aircraft engine that normally supplies oil under pressure to a chamber formed by the front portion of a crankshaft, said oil under pressure being utilized to manipulate the blade angle pitch of a constant speed, controllable pitch propeller, said chamber being subsequently sealed off at its exit end by an expansion plug that is engaged with the interior wall portion of said crankshaft forming said chamber when a fixed pitch propeller is substituted for said controllable pitch propeller, the improvement which comprises:

• a backup seal apparatus positioned downstream and adjacent to said expansion plug, said apparatus having outer peripheral walls that conform concentrically with and are sealingly engaged with said interior wall portion formed by said crankshaft to prevent escape of said oil under pressure if said expansion plug should fail, said backup seal apparatus having a first oil seal end and a second seal retaining end, said second seal retaining end positioned downstream of said first end and connected to said first seal end by a shaft means therebetween, said second retaining end having at least a pair of flanges extending outwardly therefrom 180 degrees apart adapted to accept at least two of the fixed pitch propeller retaining bolts through holes formed in said flanges to retain said backup seal apparatus within said chamber.