A leg mechanism includes an articulated leg system, a passive device and a cable. The articulated leg system has a leg portion. The passive device is coupled to the articulated leg system and is configured to apply a first force to a portion thereof. The cable is coupled to the articulated leg system and is configured to apply a second force, in opposition to the first force, to a portion thereof. When the cable is drawn away from the articulated leg system, the second force moves the leg portion in a first direction. When tension is released from the cable, the passive device exerts the first force so as to move the leg portion a second direction that is opposite the first direction.

An aircraft tail skid energy absorption indicator including a crushable indicator cartridge disposed within the an outer shock absorber canister of the aircraft tail skid, and an indicator rod coupled to the crushable indicator cartridge so as to move with a portion of the crushable indicator cartridge as a unit, where the indicator rod extends through an aperture in a wall of the outer shock absorber canister, where the indicator rod includes at least one graduation that indicates an amount of remaining energy absorption of the aircraft tail skid energy absorption indicator.

A wheel well fairing for reducing drag on an aircraft fuselage configured with an open wheel well for stowing landing gear of the aircraft. The wheel well fairing includes a Coanda fairing having a convex-shaped lower portion and an upper portion. The upper portion is configured for positioning adjacent an interior vertically-orientated sidewall of the wheel well, and the convex-shaped lower portion has a bottom surface configured to extend substantially parallel to and positioned adjacent with an outer hull surface of the fuselage. The convex-shaped lower portion is curved inwardly within the wheel well between the upper portion and bottom surface. The Coanda fairing is positioned at an aft portion of the wheel well to redirect airflow out of the wheel well in a rearward direction along the bottom hull surface of the fuselage.

A system 100 to detect aircraft ground proximity including: a transmitter 110 for transmitting a radio frequency signal along an extended landing gear 20 of an aircraft 10, a sensor 120 configured to detect a parameter of the radio frequency, and a controller 130 configured to detect a change in the detected parameter on the basis of an output of the sensor 120, and to issue a landing signal when the change in the detected parameter meets a predetermined criterion. The predetermined criterion is indicative of a certain aircraft ground proximity.

Methods and systems are provided that facilitate the maintenance of levered landing gears by monitoring the condition of the stop pads of such landing gears. One embodiment provides for calibrating a sensor for measuring a condition of a stop joint formed by a first stop pad and a second stop pad of a levered landing gear against a nominal condition of at least one of the first stop pad and the second stop pad; monitoring, by the sensor, a current condition of the at least one of the first stop pad and the second stop pad from the nominal condition; determining whether a non-conformance from the nominal condition of the at least one of the first stop pad and the second stop pad has been detected by the sensor for the current condition; and in response to determining that the non-conformance has been detected, generating an alert.

Systems and methods for mechanically rotating an aircraft about its center-of-gravity (C.sub.G) are disclosed. The system can enable the rear, or main, landing gear to squat, while the nose landing gear raises to generate a positive pitch angle for the aircraft for takeoff or landing. The system can also enable the nose gear and main gear to return to a relatively level fuselage attitude for ground operations. The system can include one or more hydraulically linked hydraulic cylinders to control the overall height of the nose gear and the main gear. Because the hydraulic cylinders are linked, a change on the length of the nose cylinder generates a proportional, and opposite, change in the length of the main cylinder, and vice-versa. A method and control system for monitoring and controlling the relative positions of the nose gear and main gear is also disclosed.

An unmanned aerial vehicle according to certain embodiments generally includes a chassis, a power supply mounted to the chassis, a control system operable to receive power from the power supply, at least one rotor operable to generate lift under control of the control system, a line having one end coupled to the chassis and an opposite free end, wherein the free end is positioned below the chassis, and a severing mechanism operable to sever the line under control of the control system.

A tow-bar fitting for connecting a tow-bar to an aircraft landing gear is disclosed including a tow-bar attachment to which, in use, the tow-bar is coupled. The tow-bar fitting also includes a first fuse member via which linear loads but not torque loads are transmitted from the tow-bar attachment to the rest of the landing gear. The first fuse member is configured to fail at a predetermined linear load threshold. The tow-bar fitting includes a second fuse member via which torque loads are transmitted from the tow-bar attachment to the rest of the landing gear. The second fuse member is configured to fail at a predetermined torque load threshold. A method of towing an aircraft is also disclosed.

A method according to certain embodiments generally involves operating a system including an unmanned aerial vehicle (UAV) and a base station. The base station includes a nest including an upper opening having an upper opening diameter and a lower opening having a lower opening diameter less than the upper opening diameter. The lower opening is accessible from within the base station. The method generally includes landing the UAV within the nest such that a portion of the UAV is accessible via the lower opening, releasably attaching a load to the UAV, and operating the UAV to deliver the load to a destination.

An unmanned aerial vehicle according to certain embodiments generally includes a chassis, a power supply mounted to the chassis, a control system operable to receive power from the power supply, at least one rotor operable to generate lift under control of the control system, a line having one end coupled to the chassis and an opposite free end, wherein the free end is positioned below the chassis, and a severing mechanism operable to sever the line under control of the control system.