Aircraft elevator feel computer test apparatus
An apparatus for testing an aircraft Elevator Feel Computer (EFC) including a test box including a housing having a base and a first cover attached to the base. The apparatus includes a pressurized air delivery subsystem with an air pump disposed entirely within the base enclosure. A pressure regulator is to adjustably regulate an air pressure delivered through a regulated air port simultaneously to first and second pitot probes. The apparatus includes a two-channel pneumatic pressure measurement subsystem including first and second pressure gages connected respectively to first and second visco drains, which are connected, respectively to the first and second pitot probes. The apparatus includes a two-channel hydraulic pressure measurement subsystem including first and second hydraulic pressure displays connected respectively to first and second hydraulic transmitters, which are to connect to first and second metered pressure hydraulic inputs of a dual feel actuator from the EFC.
1 . An apparatus for testing an aircraft Elevator Feel Computer (EFC), comprising:
a test box including a housing having a base and a first cover attached to the base;
an interface panel mounted on the base to define a base enclosure;
an electrical power supply interface including a power on-off switch and an electrical connector for connecting the apparatus to an electrical power cable;
a pressurized air delivery subsystem including:
an air pump disposed entirely within the base enclosure;
a regulated air port in selectable fluid communication with the air pump, the regulated air port disposed through the interface panel;
a pressure regulator to adjustably regulate an air pressure delivered through the regulated air port, the pressure regulator including a pressure regulator knob, located on the interface panel, for adjusting the air pressure delivered through the regulated air port;
a pump power switch disposed on the interface panel to selectably close an electrical power circuit that delivers electrical power to the air pump and to indicate whether or not the electrical power circuit is energized;
a shut off valve having a shut off valve knob disposed on the interface panel wherein the shut off valve is to selectably block the pressurized air from being delivered from the air pump to the regulated air port; and
a pressure relief valve disposed on the interface panel, the pressure relief valve to selectably exhaust pressurized air in a pneumatic circuit within the base enclosure, the pneumatic circuit connected to the regulated air port;
a two-channel pneumatic pressure measurement subsystem including:
a first air inlet connector disposed on the interface panel, the first air inlet connector to connect to a first visco drain in fluid communication with the first pitot probe;
a first pneumatic circuit to fluidically connect the first air inlet connector to a first pitot pressure gage to indicate a first pneumatic pressure in the first pneumatic circuit;
a second air inlet connector disposed on the interface panel, the second air inlet connector to connect to a second visco drain in fluid communication with a second pitot probe; and
a second pneumatic circuit to fluidically connect the second air inlet connector to a second pitot pressure gage to indicate a second pneumatic pressure in the second pneumatic circuit;
a two-channel hydraulic pressure measurement subsystem including:
a first electrical connector disposed on the interface panel, the first electrical connector to connect to a first hydraulic transmitter;
a first electrical circuit defined within the base enclosure to electrically connect the first electrical connector to a first hydraulic pressure display to indicate a first hydraulic pressure;
a second electrical connector disposed on the interface panel, the second electrical connector to connect to a second hydraulic transmitter; and
a second electrical circuit to electrically connect the second electrical connector to a second hydraulic pressure display to indicate a second hydraulic pressure.
2 . The apparatus of claim 1 wherein the pressurized air delivery subsystem further comprises:
a first pitot probe adapter to connect to a first pitot probe wherein the first pitot probe adapter is to reversibly form a pressure tight connection with the first pitot probe;
a second pitot probe adapter to connect to a second pitot probe wherein the second pitot probe adapter is to reversibly form a pressure tight connection with the second pitot probe; and
a pitot hose assembly including an air input hose, a T-fitting connected to the air input hose, a first pitot adapter hose to connect the T-fitting and the first pitot probe adapter, and a second pitot adapter hose to connect the T-fitting and the second pitot probe adapter, wherein the pressurized air delivery system is to deliver pressurized air simultaneously to the first pitot probe and the second pitot probe.
3 . The apparatus of claim 1 wherein the first pitot pressure gage and the second pitot pressure gage each include a liquid crystal display (LCD) and wherein the first pitot pressure gage and the second pitot pressure gage each have an operating span of 0 psig to 10 psig with an accuracy within 0.1 percent of the operating span.
4 . The apparatus of claim 1 wherein the pneumatic pressure measurement subsystem further comprises:
a first pressure return hose assembly to fluidically connect the first air inlet connector to the first visco drain; and
a second pressure return hose assembly to fluidically connect the second air inlet connector to the second visco drain.
5 . The apparatus of claim 1 , further comprising:
a first hydraulic signal cable to connect the first electrical connector to the first hydraulic transmitter; and
a second hydraulic signal cable to connect the second electrical connector to the second hydraulic transmitter.
6 . The apparatus of claim 1 wherein:
the first hydraulic transmitter is to fluidically connect to a first metered pressure hydraulic input of a dual feel actuator from the EFC to measure the first hydraulic pressure and transmit a signal indicative of the first hydraulic pressure; and
the second hydraulic transmitter is to fluidically connect to a second metered pressure hydraulic input of the dual feel actuator from the EFC to measure a second hydraulic pressure and transmit a signal indicative of the second hydraulic pressure.
7 . The apparatus of claim 6 wherein:
the first hydraulic transmitter is to be connected to a first hydraulic T-connector in fluid communication with the first metered pressure hydraulic input of the dual feel actuator from a first metered pressure hydraulic output of the EFC;
a first metered pressure hydraulic line is to remain connected between the first metered pressure hydraulic output of the EFC and the first metered pressure hydraulic input of the dual feel actuator during operation of the apparatus;
the second hydraulic transmitter is to be connected to a second hydraulic T-connector in fluid communication with the second metered pressure hydraulic input of the dual feel actuator from a second metered pressure hydraulic output of the EFC; and
a second metered pressure hydraulic line is to remain connected between the second metered pressure hydraulic output of the EFC and the second metered pressure hydraulic input of the dual feel actuator during the operation of the apparatus.
8 . The apparatus of claim 6 wherein:
the first hydraulic transmitter is to be connected to a first metered pressure hydraulic line in fluid communication with the first metered pressure hydraulic output of the EFC;
the first metered pressure hydraulic line is to remain connected to the first metered pressure hydraulic output of the EFC during operation of the apparatus;
the first metered pressure hydraulic line is to be disconnected from the first metered pressure hydraulic input of the dual feel actuator during operation of the apparatus;
the first metered pressure hydraulic input of the dual feel actuator is to be capped during operation of the apparatus;
the second hydraulic transmitter is to be connected to a second metered pressure hydraulic line in fluid communication with the second metered pressure hydraulic output of the EFC;
the second metered pressure hydraulic line is to remain connected to the second metered pressure hydraulic output of the EFC during operation of the apparatus;
the second metered pressure hydraulic line is to be disconnected from the second metered pressure hydraulic input of the dual feel actuator during operation of the apparatus; and
the second metered pressure hydraulic input of the dual feel actuator is to be capped during operation of the apparatus.
9 . The apparatus of claim 1 , further comprising:
at least one tethered dust cap assembly having a dust cap and a tether connected to the dust cap wherein the tether is to be fastened to the interface panel to retain the dust cap when the dust cap is removed from a coverable connector, wherein the coverable connector includes at least one of: the regulated air port, the first air inlet connector, the second air inlet connector, the first electrical connector, or the second electrical connector.
10 . The apparatus of claim 1 wherein at least one of the first hydraulic transmitter or the second hydraulic transmitter comprises:
a hydraulic pressure transducer having an operating pressure range from about 0 psi to about 3000 psi;
a hydraulic connector having ¼ inch male National Pipe Thread (NPT) threads;
an electrical connector having 4 pins; and
a signal output range from about 4 mA to about 20 mA.
11 . The apparatus of claim 1 , the test box further comprising:
a first hinge to attach the first cover to the base;
a latch to selectably secure the first cover to the base in a sealed configuration; and
a test box handle attached to the test box to facilitate lifting and carrying the test box, wherein the housing fits in a space that is about 14 inches long, about 12 inches wide, and about 6 inches tall to facilitate setup and operation of the test box in an aft galley of an airliner.
12 . An aircraft Elevator Feel Computer (EFC) test kit, comprising:
a rigid case having:
a bin;
a second cover attached to the bin by a second hinge;
a second latch to selectably secure the second cover to the bin in a closed configuration;
a test kit case handle attached to the rigid case; and
a pair of wheels attached to the rigid case, wherein the rigid case fits in a space that is about 32 inches long, about 21 inches wide, and about 12 inches tall to facilitate setup of the EFC test kit in an aft galley of an airliner;
a test box including:
a housing having a base;
a first cover attached to the base;
a first hinge to attach the first cover to the base;
a latch to selectably secure the first cover to the base in a sealed configuration;
a test box handle attached to the test box to facilitate lifting and carrying the test box, wherein the housing fits in a space that is about 14 inches long, about 12 inches wide, and about 6 inches tall to facilitate setup and operation of the test box in an aft galley of an airliner;
an interface panel mounted on the base to define a base enclosure;
an electrical power supply interface including a power on-off switch and an electrical connector for connecting the apparatus to an electrical power cable;
a two-channel pneumatic pressure measurement subsystem including:
a first air inlet connector disposed on an interface panel, the first air inlet connector to connect to a first visco drain in fluid communication with a first pitot probe;
a second air inlet connector disposed on the interface panel, the second air inlet connector to connect to a second visco drain in fluid communication with a second pitot probe;
a two-channel hydraulic pressure measurement subsystem including:
a first electrical connector disposed on the interface panel, the first electrical connector to connect to a first hydraulic transmitter;
a first electrical circuit defined within the base enclosure to electrically connect the first electrical connector to a first hydraulic pressure display to indicate a first hydraulic pressure;
a second electrical connector disposed on the interface panel, the second electrical connector to connect to a second hydraulic transmitter; and
a second electrical circuit to electrically connect the second electrical connector to a second hydraulic pressure display to indicate a second hydraulic pressure;
the electrical power cable;
a pitot hose assembly including:
an air input hose;
a T-fitting connected to the air input hose;
a first pitot adapter hose to connect the T-fitting and a first pitot probe adapter, wherein the first pitot probe adapter is to connect to the first pitot probe wherein the first pitot probe adapter is to reversibly form a pressure tight connection with the first pitot probe; and
a second pitot adapter hose to connect the T-fitting and a second pitot probe adapter, wherein the second pitot probe adapter is to connect to the second pitot probe, wherein the second pitot probe adapter is to reversibly form a pressure tight connection with the second pitot probe wherein a pressurized air delivery system is to deliver pressurized air simultaneously to the first pitot probe and the second pitot probe via the pitot hose assembly;
a first pressure return hose assembly to fluidically connect the first air inlet connector to the first visco drain and a second pressure return hose assembly to fluidically connect the second air inlet connector to the second visco drain;
a first hydraulic signal cable to connect the first electrical connector to the first hydraulic transmitter, and a second hydraulic signal cable to connect the second electrical connector to the second hydraulic transmitter;
a hose grip assembly having a suction cup and hose retainer to support hoses in an organized arrangement during setup and operation of the test box;
the first pitot probe adapter and the second pitot probe adapter;
a first pretest pin and a second pretest pin for installing in the first pitot probe adapter or the second pitot probe adapter to isolate a suspected leak during operation of the test box;
the first hydraulic transmitter and the second hydraulic transmitter; and
a bottle of lubrication fluid for lubricating the first pitot probe adapter and the second pitot probe adapter, wherein the elements of the test kit, other than the rigid case, fit entirely within the rigid case when the first cover is latched to the bin in the closed configuration.
13 . A method of using the apparatus for testing the aircraft Elevator Feel Computer (EFC) of claim 1 , comprising:
pressurizing the aircraft hydraulic systems using an electric motor driven pump or an engine-driven pump of the aircraft;
loosening the pressure regulator knob by turning the pressure regulator knob counterclockwise until the pressure regulator knob spins freely;
pushing the shut off valve knob toward the interface panel to open the shut off valve;
energizing the test box with the power on-off switch;
energizing the air pump with the pump power switch;
observing the first pitot pressure gage and the second pitot pressure gauge simultaneously;
slowly tightening the pressure regulator knob until the first pitot pressure gage and the second pitot pressure gauge each read a first target pitot pressure;
determining if one of the first pitot pressure gage or the second pitot pressure gage rises more slowly than the other, wherein a slow rising pressure in the first pitot pressure gage or the second pitot pressure gage is indicative of a restriction in the system corresponding to the slow rising pressure gage;
comparing the first hydraulic pressure indicated on the first hydraulic pressure display and the second hydraulic pressure indicated on the second hydraulic pressure display;
determining if one of the first hydraulic pressure or the second hydraulic pressure is lower than the other by more than 20 percent, wherein a lower hydraulic pressure is indicative of a restriction in the system corresponding to the lower hydraulic pressure;
pulling the shut off valve knob fully in the direction away from the interface panel to close the shut off valve;
observing the first pitot pressure gage and the second pitot pressure gauge simultaneously;
determining if one of the first pitot pressure gage or the second pitot pressure gage decreases by more than a maximum allowable pressure decay amount over a two minute time interval that begins with the pulling of the shut off valve knob, wherein a loss of more than the maximum allowable pressure decay amount over the two minute time interval is indicative of a leak; and
loosening the pressure regulator knob by turning the pressure regulator knob counterclockwise until the first pitot pressure gage and the second pitot pressure gage read within a lower pressure target range, and waiting for the pressure to stabilize before continuing to the next step.
14 . The method of claim 13 wherein the first target pitot pressure is about 2.5 psig.
15 . The method of claim 13 wherein the pitot pressure lower target range is about 0.09 psig and about 0.16 psig.
16 . The method of claim 13 wherein the maximum allowable pressure decay amount is about 0.2 psig over a 2 minute time interval.