# US 10,121,293 B2 · Pitch trim actuator servicing monitoring system and method

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- Number: US 10,121,293 B2
- Document ID: US10121293B2
- Status: Granted
- Kind: B2
- Application number: 15/481,136
- Filed: 2017-04-06
- Published: 2017-07-27
- Granted: 2018-11-06
- Earliest claimed: 2014-07-24
- Assignees: Goodrich Corporation
- Applicants: Goodrich Corporation
- Inventors: Amir M Fazeli; Adnan Cepic; Susanne M Reber
- Web page: https://patentgrep.com/patent/US10121293B2

## CPC

- G07C 5/0808: {Diagnosing performance data (testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005)}
- B64C 25/60: Oleo legs
- B64D 45/00: Aircraft indicators or protectors not otherwise provided for
- F15B 1/24: with rigid separating means, e.g. pistons
- F15B 19/005: {Fault detection or monitoring}
- B64D 2045/0085: {Devices for aircraft health monitoring, e.g. monitoring flutter or vibration}
- F15B 20/005: {Leakage; Spillage; Hose burst}
- F15B 2201/50: Monitoring, detection and testing means for accumulators
- F15B 2201/51: Pressure detection
- F15B 2201/515: Position detection for separating means
- F15B 2211/625: Accumulators
- F15B 2211/7054: Having equal piston areas
- F15B 2211/857: Monitoring of fluid pressure systems
- G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- B64C: AEROPLANES; HELICOPTERS
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR

## Abstract

A method includes detecting at least one position measurement of a separator piston of a pitch trim actuator. The method includes detecting at least one pressure measurement of an oil. The method includes detecting at least one temperature measurement of the oil. The method includes storing at least one position value based on the at least one position measurement of the separator piston, at least one pressure value based on the at least one pressure measurement of the oil and at least one temperature value based on the at least one temperature measurement of the oil. The method includes determining whether the pitch trim actuator requires servicing based on the at least one position value, the at least one pressure value, and the at least one temperature value.

## Claims

### Claim 1

A method for determining a status of fluids within a pitch trim actuator of an aircraft comprising:
detecting, by a position sensor, at least one position measurement of a separator piston of the pitch trim actuator;
detecting, by a pressure sensor, at least one pressure measurement of an oil within an oil chamber of the pitch trim actuator;
detecting, by a temperature sensor, at least one temperature measurement of the oil within the oil chamber of the pitch trim actuator;
storing, in a tangible, non-transitory memory, at least one position value based on the at least one position measurement of the separator piston, at least one pressure value based on the at least one pressure measurement of the oil and at least one temperature value based on the at least one temperature measurement of the oil;
calculating, by a processor, a volume of oil in the oil chamber of the pitch trim actuator based upon the at least one position measurement of the separator piston;
calculating, by the processor, a pressure of a gas within a gas chamber of the pitch trim actuator based upon the at least one pressure measurement of the oil within the oil chamber;
determining, by the processor, that at least one of the volume of the oil or the pressure of the gas is below a corresponding threshold value; and
determining, by the processor, whether the pitch trim actuator requires servicing in response to the at least one of the volume of the oil or the pressure of the gas being below the corresponding threshold value.

### Claim 2 (depends on 1)

The method of claim 1 wherein:
the at least one position measurement of the separator piston includes at least two position measurements of the separator piston before a landing of the aircraft;
the at least one pressure measurement of the oil includes at least two stored pressure measurements of the oil before the landing of the aircraft;
the at least one temperature measurement of the oil includes at least two stored temperature measurements of the oil before the landing of the aircraft;
the at least one position value includes an average of the at least two position measurements of the separator piston;
the at least one pressure value includes an average of the at least two stored pressure measurements of the oil; and
the at least one temperature value includes an average of the at least two stored temperature measurements of the oil.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
determining, by the processor, a total volume of oil and gas within the pitch trim actuator; and
determining, by the processor, a volume of gas in the gas chamber of the pitch trim actuator;
wherein calculating the volume of oil in the oil chamber is performed using an equation:
V
oil_
⁢
i
@
T
ˇ
oil_
⁢
i
,
1
=
(
V
tot
-
V
acc
⁡
(
S
ˇ
i
,
1
)
)
wherein
V
oil_
⁢
i
@
T
ˇ
oil_
⁢
i
,
1
represents the volume of oil in the oil chamber, Vtot represents the total volume of oil and gas within the pitch trim actuator and
V
acc
⁡
(
S
ˇ
i
,
1
)
represents the volume of gas in the gas chamber of the pitch trim actuator.

### Claim 4 (depends on 1)

The method of claim 1, further comprising calculating, by the processor, a temperature of the gas within the gas chamber of the pitch trim actuator based upon the at least one temperature measurement of the oil within the oil chamber.