Abstract: A non-pressurized accessory gearbox for an aircraft includes: a housing, one or more gears disposed within the housing, an input rotating member to receive input from a main rotor gearbox via a shaft connected to the one or more gears, and one or more output rotating members in communication with the one or more gears. The gearbox is configured to utilize splash lubrication for moving a lubrication fluid within the housing.

Abstract: A removable oil filter system includes an oil filter mount, an oil filter element removably connected to the oil filter mount, an impending-bypass indicator connected to the oil filter mount and in fluid communication with an oil in the oil filter system, and a full-bypass indicator in fluid communication with the oil filter mount. The impending-bypass indicator is capable of reporting an impending-bypass condition of the oil filter system. The full-bypass indicator is capable of reporting a full-bypass condition of the oil filter system.

Abstract: The present invention includes a fastener comprising: a fastener body having a longitudinal axis and a first external male threaded portion, and two or more through-holes perpendicular to the longitudinal axis of the fastener body in the threaded portion.

Abstract: The present invention includes an aircraft drive system comprising a main rotor gearbox comprising a first and a second input; a first drive system comprising a first engine reduction gearbox connecting a first engine to the first input of the main rotor gearbox at a reduced shaft speed; and a second drive system independent from and redundant with the first drive system, the second drive system comprising a second engine reduction gearbox connecting a second engine to the second input of the main rotor gearbox at the reduced shaft speed.

Abstract: An apparatus includes a shared cooling device for cooling one or more systems or components, and a plurality of primary cooling pathways. Each of the primary cooling pathways includes a fan, and each fan is in fluid communication with the shared cooling device.

Abstract: A cooling apparatus includes one or more fans and one or more shafts. Each of the one or more fans includes a fan blade assembly. Each of the one or more shafts is operably coupled to an engine or a gearbox that rotates the shaft. Each fan blade assembly of the one or more fans is disposed on one of the shafts.

Abstract: A ring gear includes a ring having one or more sets of inwardly facing teeth, a circumferential flange extending outward from the ring, and the flange is mounted between a first housing and a second housing. In addition, the flange protrudes into an ambient air outside the first housing and second housing.

Abstract: In one embodiment, an apparatus comprises a thermal barrier configured to surround at least a portion of a driveshaft and to protect the driveshaft from heat. The thermal barrier comprises an inner wall forming a cavity in which the driveshaft lies, an outer wall enclosing the inner wall, and a space between the inner wall and the outer wall. The space is evacuated and forms a vacuum.