Method of servicing a gas turbine engine

Patent metadata

Field	Value
Publication number	US-9259808-B2
Application number	US-201213716648-A
Country	US
Kind code	B2
Filing date	Dec 17, 2012
Priority date	Dec 22, 2011
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

A gas turbine engine 10 is provided with rigid raft assemblies 290 , which may be electrical harness raft assemblies 290 comprising electrical conductors embedded in a rigid composite material. The rigid raft assemblies 290 can be provided with engine dressings, such as pipework and ECUs to produce an electrical raft assembly. In order to assemble or dress the gas turbine engine 10 , the rigid raft assemblies can be pre-prepared to incorporate at least a part of at least one gas turbine engine system/component before being installed on the gas turbine engine 10 . During maintenance, whole raft assemblies can be removed and replaced with corresponding, pre-prepared assemblies. This can save considerable time during engine build and maintenance.

First claim

We claim:

1. A method of servicing a gas turbine engine, the method comprising:
removing a first rigid raft assembly that is directly attached to only one of a fan casing or a core casing from the gas turbine engine, the rigid raft assembly incorporating at least a part of at least one component or system of the gas turbine engine; and
installing a second, pre-prepared, rigid raft assembly directly onto the one of the fan casing or the core casing of the gas turbine engine in place of the first raft assembly,
wherein the first and second rigid raft assemblies are electrical harness raft assemblies having electrical conductors embedded in a rigid material so as to be surrounded by, and fixed in position by, the rigid material along an entire length of the electrical conductors, the electrical conductors being at least a part of an electrical system arranged to transfer electrical signals around the engine.

2. The method of servicing a gas turbine engine according to claim 1 , wherein the first and second rigid raft assemblies are dressed rigid raft assemblies comprising a rigid mounting surface on which at least a part of at least one of the components or systems of the gas turbine engine is mounted.

3. The method of servicing a gas turbine engine according to claim 2 , wherein the rigid mounting surface of each of the first and second rigid raft assemblies has a pipe for transferring fluid around the engine attached thereto, the pipe being at least a part of a fluid transfer system.

4. The method of servicing a gas turbine engine according to claim 3 , wherein:
the step of removing the first rigid raft assembly comprises disconnecting the respective pipe from another part of the fluid transfer system; and
the step of installing the pre-prepared second raft assembly comprises connecting the respective pipe the other part of the fluid transfer system.

5. The method of servicing a gas turbine engine according to claim 2 , wherein each of the first and second rigid raft assemblies has, attached to its respective rigid mounting surface, one or more of the following components or systems selected from the group consisting of: an ECU; a fire detection system; a thermocouple; a vibration monitoring system; a fluid pressure monitoring system; and a fluid quality measuring system for monitoring fluid pressure in pipes mounted to the respective rigid raft assembly.

6. The method of servicing a gas turbine engine according to claim 1 , further comprising:
removing the gas turbine engine on which the first rigid raft assembly is installed from an airframe before the step of removing the first rigid raft assembly from the gas turbine engine; and
refitting that gas turbine engine to an airframe after the step of installing the second, pre-prepared, rigid raft assembly thereon.

7. The method of servicing a gas turbine engine according to claim 1 , wherein:
the first rigid raft assembly has an electrical harness raft which comprises electrical conductors arranged to transfer electrical signals around the engine embedded in a rigid material, the first electrical harness raft assembly being electrically connected to another electrical component of the gas turbine engine using a flexible cable; and
the step of removing the first rigid raft assembly from the gas turbine engine comprises disconnecting the flexible cable from the first electrical harness raft.

8. A method of servicing a fleet of gas turbine engines, the method comprising:
removing a first rigid raft assembly that is directly attached to only one of a fan casing or a core casing from the gas turbine engine, the rigid raft assembly incorporating at least a part of at least one component or system of the gas turbine engine; and
installing a second, pre-prepared, rigid raft assembly directly onto the one of the fan casing or the core casing of the gas turbine engine in place of the first raft assembly,
servicing the first rigid raft assembly that has been removed from the first gas turbine engine; and
installing the serviced first rigid raft assembly onto a second gas turbine engine,
wherein the first and second rigid raft assemblies are electrical harness raft assemblies having electrical conductors embedded in a rigid material so as to be surrounded by, and fixed in position by, the rigid material along an entire length of the electrical conductors, the electrical conductors being at least a part of an electrical system arranged to transfer electrical signals around the engine.

9. The method of servicing a fleet of gas turbine engines according to claim 8 , wherein
the step of servicing the first rigid raft assembly comprises removing engine dressings from the first rigid raft assembly.

10. The method of servicing a fleet of gas turbine engines according to claim 8 , further comprising:
removing the gas turbine engine on which the first rigid raft assembly is installed from an airframe before the step of removing the first rigid raft assembly from the gas turbine engine; and
refitting that gas turbine engine to an airframe after the step of installing the second, pre-prepared, rigid raft assembly thereon.

11. The method of servicing a fleet of gas turbine engines according to claim 8 , wherein:
the first rigid raft assembly has an electrical harness raft which comprises electrical conductors arranged to transfer electrical signals around the engine embedded in a rigid material, the first electrical harness raft assembly being electrically connected to another electrical component of the gas turbine engine using a flexible cable; and
the step of removing the first rigid raft assembly from the gas turbine engine comprises disconnecting the flexible cable from the first electrical harness raft.

12. The method of servicing a fleet of gas turbine engines according to claim 8 , wherein the method further comprises testing the serviced first rigid raft assembly before installing it onto the second gas turbine engine.

13. A method of dressing a gas turbine engine comprising:
preparing a rigid raft assembly for installing on the gas turbine engine, the rigid raft assembly incorporating at least a part of at least one component or system of the gas turbine engine;
storing the prepared rigid raft assembly in a storage facility; and
when the gas turbine engine requires dressing, installing the prepared rigid raft assembly on the rest of the gas turbine engine such that the rigid raft assembly is attached directly to only one of a fan casing or a core casing, the prepared rigid raft assembly forming at least a part of the engine dressing,
wherein the rigid raft assembly is an electrical harness raft assembly having electrical conductors embedded in a rigid material so as to be surrounded by, and fixed in position by, the rigid material along an entire length of the electrical conductors, the electrical conductors being at least a part of an electrical system arranged to transfer electrical signals around the engine.

14. The method of dressing a gas turbine engine according to claim 13 , wherein the rigid raft assembly is a dressed rigid raft assembly comprising a rigid mounting surface on which at least a part of at least one of the components or systems of the gas turbine engine is mounted.

15. The method of dressing a gas turbine engine installation according to claim 13 , wherein:
the step of installing the prepared rigid raft assembly comprises connecting the rigid raft assembly, including the components and/or systems incorporated in the rigid raft assembly, to the gas turbine engine; and/or
the step of installing the prepared rigid raft assembly comprises

Assignees

• Rolls Royce Plc

Inventors

• Broughton Paul
• Peace Richard

Classifications

• Y10T29/49238

  Repairing, converting, servicing or salvaging · CPC title

• B23P6/005 Primary

  using only replacement pieces of a particular form · CPC title

• Y02T50/672

  Cross-Sectional Technologies · mapped topic

• F02C7/32 Primary

  Arrangement, mounting, or driving, of auxiliaries · CPC title

• F02C7/20

  Mounting or supporting of plant; Accommodating heat expansion or creep · CPC title