Abstract: A method of obtaining data with a sensor of an autonomous underwater vehicle (AUV), the AUV comprising a bladder which contains a gas and is exposed to ambient water pressure. A downward thrust force is generated which causes the AUV to descend through a body of water, wherein the bladder contracts as the AUV descends due to an associated increase in the ambient water pressure, the contraction of the bladder causing the gas to compress and the AUV to become negatively buoyant. Next the AUV lands on a bed of the body of water. After the AUV has landed on the bed, the sensor is operated to obtain data with the AUV stationary and negatively buoyant and a weight of the AUV supported by the bed.

Abstract: A marine thruster includes a cylinder with a front opening and a rear opening; radial baffles positioned within an interior of the cylinder to separate the interior into equally divided water chambers; pistons positioned within a corresponding one of the equally divided water chambers; and an inner-ring rotary valve engaged with the cylinder to allow for side intake of water and the separation of each of the equally divided water chambers into a dry section and a wet section by pistons; the pistons engage with a power source, the power source providing axial reciprocating motion; and the pistons push water through the equally divided water chambers.

Abstract: The invention relates to a center-axis oarlock and methods of providing constant gearing throughout the arc of an oar in a boat or shell.

Abstract: Embodiments of a watercraft are disclosed herein. One embodiment of a watercraft includes a board and a propulsion system secured to the board. The propulsion system has a water outlet portion and a water intake portion. The water intake portion includes a rim having a cross-sectional area that tapers along a length of the rim in a direction moving toward the water outlet portion. The propulsion system further includes a first blade having a first end connected to the rim and a second end opposite the first end. The second end of the first blade is a free floating end. The propulsion system also includes a first motor located between the water outlet portion and the water intake portion. The first motor has a first rotor component and a first stator component. The first rotor component is configured to rotatably drive the rim.

Abstract: Example transmissions for rotating coaxial drive shafts in opposite directions are described herein. An example apparatus includes a first face gear coupled to a first drive shaft, a first elliptically interfacing gear coupled to a second drive shaft and facing toward the first face gear, the second drive shaft disposed within and coaxially aligned with the first drive shaft, and a wobble plate disposed between the first face gear and the first elliptically interfacing gear. The wobble plate has a second face gear on a first side of the wobble plate engaged with the first face gear and a second elliptically interfacing gear on a second side of the wobble plate engaged with the first elliptically interfacing gear. The wobble plate is to rotate the first face gear and the first elliptically interfacing gear in opposite directions.

Abstract: A rudder blade is provided with a rudder blade hub, which, in comparison to rudder blades known from the prior art, has a lower overall weight and can be produced with a reduced outlay on materials and costs, while simultaneously ensuring a sufficiently high strength in order to be able to absorb the large forces and torques acting during operation of the rudder blade and to be able to conduct them away to a rudder stock. The rudder blade includes a leading edge, a trailing edge, a first side wall and a second side wall lying opposite the first side wall, and a rudder blade hub, which is arranged in a connection space, for connecting a rudder stock. The rudder blade hub has a hub body including an inner bore for receiving the rudder stock, and a hub outer surface running in the circumferential direction, for the hub outer surface to be entirety spaced apart from an inner side of the first side wall and from an inner side of the second side wall.

Abstract: A ballast water treatment apparatus 1 comprises a ballast pipe 11 which guides ballast water to a ballast tank 60 and a sterilizing agent supply unit 30 which supplies a constant amount of a sterilizing agent per unit time to the ballast pipe 11 in accordance with a flow rate of ballast water flowing in the ballast pipe 11. A ballast water treatment method using the ballast water treatment apparatus 1 comprises steps of supplying ballast water to a ballast tank 60 via a ballast pipe 11 and supplying a constant amount of a sterilizing agent 33 per unit time to the ballast pipe 11 in accordance with a flow rate of the ballast water flowing in the ballast pipe 11.

Abstract: An aerodynamic cover panel for a landing gear wheel well in an undercarriage of an aircraft includes at least one embodiment having a peripheral lip that defines a plane. Movements of the cover panel to open and close the wheel well are confined to pivotal rotation within the plane, and occur within an aerodynamic boundary layer of the undercarriage about a pivot axis in one rotational direction to open the wheel well, and in an opposite rotational direction to close the wheel well. The cover panel includes a flange, to which a rotary shaft is secured at one end for rotation about the pivot axis. The other end of the rotary shaft is secured to an actuator fixed within the undercarriage. In one embodiment, the cover panel rotates about an arc of least 75° between fully opened and fully closed positions of the wheel well.

Abstract: A monument arrangement for a cabin of a vehicle has a first monument, with a washroom formed therein, a second monument and an aisle. The first and second monuments enclose the aisle, wherein an access opening to the washroom is directed toward a side wall of the second monument and is adjacent to the aisle. The distance between the access opening and the relevant side wall of the second monument is at most 1 m, and the side wall of the second monument has a first, rigid side wall portion and at least one second side-wall portion, which is mounted on the first side wall portion such that it can be pivoted about a vertical axis and which can be pivoted from a neutral position, running in the direction toward the first side wall portion, into an angled position, directed away from the first monument and the aisle.

Abstract: A flight deck barrier door for an aircraft, the flight deck barrier door including a door frame and a door panel in the door frame. The door panel has a plurality of vents. The door panel and door frame have a minimum total vented surface area of 1000 square inches.

Abstract: Fuselage assemblies, over-frame blanket assemblies, and methods of installing over-frame blanket assemblies are provided. A fuselage assembly for an aircraft includes a fuselage skin, a cabin liner, and an over-frame blanket assembly. The cabin liner has an outer side facing the fuselage skin. The over-frame blanket assembly is disposed between the fuselage skin and the cabin liner and has a first blanket piece. The first blanket piece includes a first sound barrier layer that defines a first outer surface of the over-frame blanket assembly and a first sound absorbing layer that defines a second outer surface of the over-frame blanket assembly facing the fuselage skin. A method of installing the over-frame blanket assembly includes positioning the first blanket piece in an orientation such that the first sound barrier layer is directly adjacent the cabin liner.

Abstract: Aircraft, aircraft wings and associated shear ties are disclosed. An example apparatus includes a first panel coupled to a second panel to define a wing box; a rib disposed chordwise within the wing box; and a stringer disposed spanwise within the wing box immediately adjacent at least one of the first panel or the second panel, the rib including a shear tie including first and second legs extending in opposite directions, the first and second legs to be coupled to at least one of the first panel, the second panel, or the stringer.

Abstract: A closed-angle composite airfoil spar is provided for an airfoil assembly. The composite airfoil spar comprises a web portion having a thickness. The composite airfoil spar also comprises a flange portion having a thickness. The flange portion extends transverse to the web portion. The composite airfoil spar further comprises a radius portion interconnecting the web and flange portions. The radius portion is an acceptable amount thinner relative to thickness of the web portion and thickness of the flange portion based on design requirements and material properties.

Abstract: An aerofoil has at least one space frame and at least one pre-stressed cover supported by the space frame. The space frame has one or more structural members, the structural members including a structural foam material; and the pre-stressed cover forms at least a part of an external aerodynamic surface of the aerofoil.

Abstract: A thermal management system for transferring heat from a heat load includes a composite structural member that supports a heat load source and a heat transfer member in thermal contact with the composite structural member, and in thermal contact with a heat sink. The system further includes at least one thermally-conductive first fastener that is in thermal contact with the heat transfer member, couples the heat load source to the composite structural member, and conducts heat from the heat load source into the heat transfer member. The heat transfer member conducts heat from the thermally-conductive first fastener to the heat sink.

Abstract: An example method of mounting a first component to a second component includes receiving at least a fastening assembly within an aperture established in the first component, the fastening assembly coupled to the second component via a linking member, positioning a felt metal material between the fastening assembly and the first component, securing the fastening assembly, and compressing the felt metal material during the securing.

Abstract: A self-adjusting flight control system is disclosed. In various embodiments, an input interface receives an input signal generated by an inceptor based at least in part on a position of an input device comprising the inceptor. A processor coupled to the input interface determines dynamically a mapping to be used to map input signals received from the inceptor to corresponding output signals associated with flight control and uses the determined mapping to map the input signal to a corresponding output signal. The processor determines the mapping at least in part by computing a running average of the output signal over an averaging period and adjusting the mapping at least in part to associate a neutral position of the input device comprising the inceptor with a corresponding output level that is determined at least in part by the computed running average.

Abstract: A method for operating a motor controller includes obtaining an electrical signal via a port on the motor controller and selecting a motor control parameter from a plurality of different motor control parameters based on the electrical signal. The port is configured to be electrically connected to a motor. The motor controller is configured to control the motor based on the selected motor control parameter.

Abstract: A starter air valve comprising a housing comprising an inlet at a first end and an outlet at a second end opposite the first end, the inlet being fluidly connected to the outlet through a fluid pathway; a valve injected into the fluid pathway dividing the fluid pathway into a first chamber and second chamber, the valve in operation adjusts fluid flow through fluid pathway; an actuator operably connected to the valve; a solenoid in variable electrical connection with the actuator; and a rotary spool valve fluidly connected to the first chamber, the rotary spool valve operable to rotate to at least one of a normal start position, a full manual override position, and a plurality of partial manual override positions, wherein the rotary spool valve is in variable fluid connection with the actuator, wherein the solenoid is in variable electrical connection with the actuator through the rotary spool valve.

Abstract: A method and apparatus are presented. An active flow control system comprises a flow control valve, a manifold, and a temperature control system. The flow control valve is configured to control a flow of air into the manifold. The manifold is operatively connected to a number of actuators. The temperature control system is configured to heat at least a portion of the flow of air.

Abstract: A shrink mechanism for use with a landing gear of an aircraft is provided. The landing gear includes an outer sleeve at least partially surrounding a shock strut, the shrink mechanism has a shaft rotatably coupled to the outer sleeve about a shaft rotation axis, the shaft being disposed perpendicular to a centerline of the shock strut, an anchor arm coupled to the shaft, the anchor arm being configured to couple to a structure within a wing of the aircraft, a shrink arm coupled to the shaft, the shrink arm and the anchor arm being coupled to the shaft so as to rotate as a unit with the shaft about the shaft rotation axis, and a shrink link rotatably coupled to the shrink arm, the shrink link being configured to rotatably couple to the shock strut.

Abstract: An aircraft landing gear 2 is disclosed having a first arm 6a configured to have one or more wheels 8a mounted at one end, the first arm 6a being configured for mounting to a pivot 10a. The landing gear 2 includes a second arm 6b configured to have one or more wheels 8b mounted at one end, the second arm 6b being configured for mounting to a pivot 10b. The landing gear 2 further includes a first link 18a pivotally coupled to the first arm 6a, a second link 18b pivotally coupled to the second arm 6b; and a main link 20 pivotally coupled to each of the first and second links 18a, 18b and to a shock absorber 22 arranged to provide a biasing force via (i) the main linkage 20 and the first link 18a which opposes rotation of the first arm 6a about the pivot 10a and (ii) the main linkage 20 and the second link 18b which opposes rotation of the second arm 6b about the pivot 10b.

Abstract: An electronic braking arrangement includes a brake stack assembly, a driver circuit, a current limiter circuit, and a voltage limiter circuit. The driver circuit is operably connected to the brake stack assembly. The current limiter circuit and the voltage limiter circuit are connected in series between the driver circuit and the brake stack assembly to drive friction brake loads in the brake stack assembly with a voltage limited constant drive current.

Abstract: A buoyancy method for deploying a plurality of floats of a buoyancy system of an aircraft. The plurality of floats comprises a plurality of main floats and a plurality of secondary floats that are folded in flight. The method comprises a step of deploying the main floats in flight prior to ditching, and a step of deploying the secondary floats after ditching.

Abstract: A control system for resonant inertial actuators estimates operating parameters of the resonant inertial actuators based on voltage and current feedback and dynamically limits selected parameters to maintain the safe, efficient, and cost effective operation of the resonant inertial actuators. Resistance within the electrical drives for the resonant inertial actuators is estimated from the voltage and current feedback and in conjunction with the modeling of the resonant inertial actuators other operating parameters are calculated or otherwise estimated. Having regard for the responsiveness of the resonant inertial actuators to changes in command signals, the command signals are adjusted to dynamically limit the estimated parameters.

Abstract: The invention relates to a drive system for a vehicle, comprising at least one asymmetrical rotor (18), which has at least one rotor blade (20) extending radially from a rotor axle, and a counterweight (22) which is opposite the rotor axle, the system further comprising a control device for the electric motor (24), which connects the electric motor (24) to a battery for the power supply thereof, and is configured and designed, during a revolution cycle, which includes 1-3 revolutions of the rigid rotor blade (20), to bring about at least one acceleration phase, in which the electric motor (24) can be accelerated to accelerate the rotor (18), and at least one braking phase, in which the electric motor (24) can be braked, the control device being designed, during at least part of the braking phase, to connect the electric motor (24) to at least one battery element (28) in generator mode.

Abstract: Systems, methods, lift fans, and aircraft involving active flow control of a ducted fan or fan-in-wing configuration are described.

Abstract: A hub system comprises at least one yoke, at least one shear bearing, and at least one mast adapter. The at least one mast adapter is configured to support the at least one yoke and the at least one shear bearing, and the at least one yoke has a flapping hinge that is non-coincident with a flapping hinge of the at least one shear bearing. Another hub system comprises a stacked yoke and a mast adapter. The mast adapter is configured to transfer rotation from a rotor mast to the hub system to rotate the hub system about a central axis of rotation. The mast adapter is further configured to support the stacked yoke such that each yoke in the stacked yoke is configured to accommodate at least some amount of rotation about an axis that is perpendicular to or about perpendicular to the central axis of rotation.

Abstract: An autopilot actuator includes first and second motors each including a rotatable motor output shaft such that either one or both of the motors can drive an actuator output shaft. An autopilot main unit enclosure is removably mounted to the helicopter proximate to a cyclic control and commonly houses autopilot actuators as well as main autopilot electronics. A cyclic vibration isolator is removably supported by an actuator shaft for co-rotation and coupled to the cyclic control to attenuate a cyclic vibration frequency at the actuator shaft while output rotations of the actuator shaft below a resonant frequency are coupled to the cyclic control. A force limited link includes first and second ends and a variable length between. The force limited link having a relaxed length when less than an unseating force is applied and the variable length changes when an applied force exceeds the unseating force to permit pilot override.

Abstract: Systems and methods are contemplated for favorably improving flight dynamics of aircraft, including enhanced aerodynamic braking and improved flight maneuverability. Air braking systems selectively position a first set of blades at a negative thrust pitch to product a net negative thrust across first and second sets of blades, while balancing torque of the drive shafts to zero. First and second sets of IBC blades can be driven by the same shaft or torque-linked shafts. Flight maneuver systems operate a powerplant at a high power mode, and dissipate the energy from the high power output by positioning a first set of IBC blades at a low efficiency pitch while maintaining constant thrust. As increased or rapid flight maneuverability is required, the first set of blades is positioned toward a high efficiency pitch to instantly increase thrust to the aircraft without requiring a related increase in energy output from the powerplant.

Abstract: An aircraft includes a fuselage and a pair of symmetric fixed wings. The fuselage includes a head and a tail spaced from the head along a longitudinal axis. Each fixed wing extends along a lateral axis. The fuselage further includes a top and a bottom spaced from the top along a vertical axis. Each symmetric fixed wing includes a first propelling mechanism mounted thereto. Each first propelling mechanism is operable to pitch about the lateral axis together with one of the symmetric fixed wings or to pitch independently about the lateral axis. A simple control device is mounted along the longitudinal axis between a center of gravity of the fuselage and the tail and is configured to generate a resistance to a torque between the center of gravity of the fuselage and the head. The simple control device is selectively operable to generate an upward or downward control torque.

Abstract: Disclosed is a multipurpose air vehicle including a frame (1) on which a propeller (11) and a mechanical unit (10) equipped with an engine are mounted, and a cabin (2) is coupled inside the frame (1). The frame (1) is constructed by upper and lower circular plates (101, 102) and curved posts (111, 112, 113, 114) that interconnect the upper and lower circular plates (101, 102), and is provided with two or more arms (12) that can protrude and retract, and a propeller (11) is provided on the tip end of each arm (12). The cabin (2) includes a circular plate member (3) and further includes at least four connectors (21) provided on the front, the rear, the left, and the right ends thereof, and each connector (21) has a tip end installed on a rail (13) of the frame (1) so as to guide pivoting of the cabin (2). The multipurpose air vehicle may freely perform upward and downward movement and forward and rearward movement, and thus may be used anywhere in the air, ground, or water.

Abstract: A droneboarding system is disclosed. The droneboarding system includes an unmanned aerial vehicle (drone) for pulling a droneboarder riding a board over a surface, a harness, a tow handle and a plurality of tension lines. Each tension line is attached to the drone and to either the tow handle or the harness. The tension lines are configured in a manner that provides mechanical control of the flight path of the drone. A remote power supply is adapted to be carried by the droneboarder. One of the tension line carries an electrical conductor from the remote power supply to the drone. The electrical conductor provides electrical power from the remote power supply to the drone.

Abstract: A droneboarding system is disclosed. The droneboarding system includes an unmanned aerial vehicle (drone) for pulling a droneboarder riding a board over a surface, a harness, a tow handle and a plurality of tension lines. Each tension line is attached to the drone and to either the tow handle or the harness. The tension lines are configured in a manner that provides mechanical control of the flight path of the drone. A remote power supply is adapted to be carried by the droneboarder. One of the tension line carries an electrical conductor from the remote power supply to the drone. The electrical conductor provides electrical power from the remote power supply to the drone.

Abstract: A vehicular alert system includes an autonomous aerial vehicle and a central computer. The autonomous aerial vehicle includes a processor, a display, and a detector. The processor controls a data transceiver. The detector detects one or more vehicular condition. The central computer communicates with the autonomous aerial vehicle via the data transceiver. The central computer includes a memory device. The memory device stores vehicular condition data and road condition data. The central computer communicates one of a vehicular condition or a road condition to the autonomous aerial vehicle. The processor of the autonomous aerial vehicle displays the received condition on the display.

Abstract: An air-conditioning system includes a motor vehicle, in particular a passenger vehicle, and a drone. The drone is configured to be secured, in a secured state, to the motor vehicle and released from the motor vehicle. The drone is a flying drone that is driven using propellers. The drone, in the secured state, serves to air-condition the motor vehicle using the propellers by pushing air into the passenger vehicle through a roof of the vehicle. The roof defines openings that correspond to a propeller circumference that allow air, generated by the propellers, to flow into the passenger vehicle.

Abstract: Methods and apparatus to harvest renewable energy are provided herein. In some embodiments, a wind-powered aircraft includes an airframe suitable for untethered flight in an open airspace; and an airborne kinetic energy conversion system attached to the airframe, the airborne kinetic energy conversion system comprising a turbine, a generator connected to the turbine, and an energy storage means connected to the generator.

Abstract: A droneboarding system is disclosed. The droneboarding system includes an unmanned aerial vehicle (drone) for pulling a droneboarder riding a board over a surface, a harness, a tow handle and a plurality of tension lines. Each tension line is attached to the drone and to either the tow handle or the harness. The tension lines are configured in a manner that provides mechanical control of the flight path of the drone. A remote power supply is adapted to be carried by the droneboarder. One of the tension line carries an electrical conductor from the remote power supply to the drone. The electrical conductor provides electrical power from the remote power supply to the drone.

Abstract: According to an aspect, a package transport container for a UAV includes a manifest device having a computer processor, a receptacle including a base that secures contents of the receptacle, a locking mechanism that couples the manifest device to the receptacle during transport, and a connector coupling the manifest device to the UAV. The processor transmits material properties of the contents of the receptacle to the UAV, receives routing information for a package to be transported, monitors coordinates of the package transport container during transport, and upon determining the coordinates match coordinates of a delivery location specified in the routing information: sends a release request signal to the UAV to release the receptacle; receives a release command from the UAV; and disengages the locking mechanism to release the manifest device from the base. The routing information is determined at least in part based on the material properties of the contents.

Abstract: The mobile platform cabin (20) disclosed herein comprises a passenger portion (22), a first cargo portion (24) disposed aft of the passenger portion (22), a partition (36) separating the passenger portion (22) from the first cargo portion (24), a second cargo portion (26) disposed aft of the first cargo portion (24) and a barrier net (38) separating the first cargo portion (24) from the second cargo portion (26). The first cargo portion (24) comprises a cargo-receiving zone (40) and a stay-out zone (44) in which cargo is not permitted. The barrier net (38) is configured to distend into the first cargo portion (24) when restraining forward movement of cargo (48) in the second cargo portion due to the cargo (48) in the second cargo portion being subjected to an acceleration relative to the cabin. At least part of the distension of the barrier net (38) is accommodated by the stay-out zone (44) of the first cargo portion (24).

Abstract: An in-flight service cart (1) for use on an aircraft for maintaining a payload such as foodstuffs and the like within a selected temperature range, said in-flight service cart (1) including: a housing (3) having a storage volume; and at least one thermally insulated container (5) removably mounted within the housing (3), said container having an outer casing (7), a thermally conductive inner casing (11), thermal insulation (9) located between the outer casing (7) and the inner casing (11), said thermal insulation including at least one vacuum insulation panel (9a-e), a payload volume for storing foodstuffs, an opening (29,47) providing access to the payload volume, a closure member (13) for closing the opening (29,47), at least one thermal energy storage unit (15) located within the inner casing (11), said thermal energy storage unit(s) (15) including a phase change material that is arranged to change phase at a temperature greater than or equal to ?10° C.

Abstract: A header assembly including a structural core member, at least one branding panel removably coupled to the structural core member, and at least one quick-connect coupling having a first quick-connect portion coupled to the structural core member and a second quick-connect portion coupled to the at least one branding panel, the second quick-connect portion being configured to mate with the first quick-connect portion to removably couple the at least one branding panel to the structural core member.

Abstract: Class dividers for aircraft passenger cabins comprising pivoting luggage bins (20) are disclosed. The class divider comprises a curtain (24B) mounted inside the passenger cabin to extend into a space allotted for movement of the pivoting luggage bin. The curtain (24B) is resiliently deformable to accommodate the movement of the pivoting luggage bin (20).

Abstract: An aircraft passenger seat having a dynamic breakover assembly includes a seat bottom frame and a seat back pivotally-mounted to the seat bottom frame that allows the angle of the seat back relative to the seat bottom frame to be varied from an upright taxi takeoff and landing (TTOL) position to a reclined position. The seat may include a means for sensing acceleration corresponding to a force indicative of an abnormal event; and a breakover mechanism coupled to the seat bottom frame and the seat back in which the means for sensing acceleration is coupled to the breakover mechanism. The breakover mechanism can prevent movement of the seat back in a forward direction past the TTOL position during normal use, and permit forward movement of at least a portion of the seat back in the forward direction past the TTOL position upon activation by the means for sensing acceleration.

Abstract: The present disclosure provides a swivel stop comprising a rotating member, a first boss coupled to the rotating member and a second boss coupled to the rotating member, and a second plate having a first interference surface and a second interference surface. An interference between the first boss and the first interference surface and the second boss and the second interference surface tends to limit the rotation of the rotating member with respect to the second plate. The swivel stop may further comprise a rail wherein the second plate is configured to translate along the rail.

Abstract: Tubular bodies for use in frames for seats of vehicles such as aircraft are described. A tube can include a sidewall that has a variable thickness along the length of the tube. The variable thickness of the sidewalls can result in the tube having a variable inner diameter along the length of the tube. The tube may also include a variable outer diameter.

Abstract: A servo valve for an actuator is described. The servo valve comprises a housing having a plurality of ports, a sleeve disposed within the housing, the sleeve comprising an axis (A), an inner surface defining a cavity for the servo valve and a plurality of metering holes, each in communication with one of the ports, and a metering rod extending axially in the cavity for reciprocation along the axis to meter flow through the metering holes. The servo valve additionally comprises a first spring seal extending between the metering rod and the sleeve to close off a first end of the cavity and a second spring seal extending between the metering rod and the sleeve to close off a second, opposite end of the cavity.

Abstract: A servo valve for an actuator is described. The servo valve comprises a housing and a sleeve provided within the housing having a plurality of metering holes for communication with a cavity within. The servo valve further comprising a metering rod provided with metering members on a central rod for metering flow into and out of the cavity through the metering holes. The metering members comprise annular elements which are located axially on the central rod by an interference fit. The position of the metering members can be adjusted through using heat to thermally expand the metering member relative to the central rod to release the hold of the friction fit, allowing the metering member to be repositioned by being slid along the central rod.

Abstract: Disclosed is an area sensor for air quality in the cockpit, crew rest or other area of an aircraft. Noxious fumes, fuel vapors, carbon monoxide and other vapors can cause significant risks to the flight crew of an aircraft. Fumes may cause drowsiness, inattentiveness or confusion to the pilot of an aircraft placing all persons on board an aircraft in danger. There exists a need to monitor and warn the cabin crew of such an event so that measures can be taken, such as donning an oxygen mask, to mitigate the fumes. Many of the vapors encountered that can cause this issue are colorless and/or odorless and therefore not always detected by the flight crew especially if they are in sufficient quantities and exposure is long enough to compromise the pilots cognitive skills.

Abstract: An aircraft comprising a main engine to provide a supply of bleed air, an APU housing within an APU compartment and having an APU bleed valve, an APU bleed air duct connecting main engine with the APU, and a bleed air heating system for the APU compartment comprising an auxiliary pipeline connecting the APU bleed air duct with the APU compartment, a temperature sensor, an auxiliary pipeline valve to control the discharge of bleed air into the APU compartment, and a temperature controller configured to establish a heating operation mode, when the sensed temperature falls below a minimum temperature threshold value, and a standby operation mode, when the sensed temperature surpasses a maximum temperature threshold value. The temperature controller operates the main engine and the valves to establish these operation modes.