Abstract: A blade tracking system for a rotary wing aircraft includes a blade sensor mounted on a blade of the rotary wing aircraft, the blade sensor wirelessly transmitting blade data; a reference sensor mounted to the rotary wing aircraft, the blade driven by the rotor hub, the reference sensor transmitting reference data; and a processor receiving the blade data and the reference data, the processor determining at least one of lead-lag, flap and pitch of the blade in response to the blade data and the reference data.

Abstract: A lubrication system includes an external pump system which pumps air out of the housing and develop negative pressure therein in response to a loss of lubrication condition. The negative pressure operates as an air lock to minimize or prevent lubricating oil loss from the housing while an internal lubrication system continues to distribute lubricating oil—which although now increasing in temperature—still operates to lubricate the gearbox components. For further ballistic tolerance, the housing is a compound housing that reduces or closes the penetration and further minimizes lubricating oil and negative pressure loss. The housing may be still further hardened by an armor layer.