Method and apparatus for engine hot section maintenance

1 . A method of servicing an aircraft engine mounted to an aircraft, the aircraft engine having a central axis and a case assembly including a first case secured to a second case and being axially offset from one another, the method comprising:

while the aircraft engine remains mounted to the aircraft:

radially supporting, relative to the central axis, an end of a shaft of the aircraft engine through a central passage extending axially through the first case with a shaft supporting rod;

creating a gap between the first case and the second case by axially moving the first case away from the second case and relative to the shaft while preventing axial and radial movements of the shaft relative to the central axis;

radially and axially supporting the shaft at the gap; and

removing the first case by disconnecting the end of the shaft from the shaft supporting rod while maintaining the shaft radially and axially supported at the gap.

2 . The method of claim 1 , wherein the radially supporting of the end of the shaft includes:

inserting the shaft supporting rod through the central passage defined by the first case; and

locking the shaft supporting rod to the shaft.

3 . The method of claim 2 , comprising detachably mounting the shaft supporting rod to a support fixture assembly mounted to the case assembly of the aircraft engine.

4 . The method of claim 3 , comprising:

mounting a static member of the support fixture assembly to a case of the case assembly, the case being distinct from the first case;

mounting a mobile member of the support fixture assembly to the first case, the mobile member slidably engaged to the static member of the support fixture assembly.

5 . The method of claim 4 , wherein the inserting of the shaft supporting rod includes:

securing a brace fixture of the support fixture assembly to the static member of the support case assembly; and

securing the shaft supporting rod to the static member of the support case assembly via the brace fixture.

6 . The method of claim 4 , wherein the creating of the gap includes:

axially locking the shaft supporting rod to the static member of the support fixture assembly;

exerting a pushing force on the shaft supporting rod with an actuator, the pushing force being counteracted by a pulling force exerted on the first case.

7 . The method of claim 6 , wherein the actuator has an outer member being slidable relative to an inner member, the inner member defining a central bore for slidably receiving the shaft supporting rod, the exerting of the pushing force on the shaft including:

inserting the shaft supporting rod through the central bore of the inner member of the actuator;

axially locking the outer member of the actuator to the first case; and

exerting the pushing force on a stopper defined by the shaft supporting rod thereby exerting the pulling force on the first case.

8 . The method of claim 7 , wherein the axially locking of the outer member of the actuator to the first case includes:

securing the outer member of the actuator to a pad;

securing an adaptor to an inter-shaft of the first case, the inter-shaft rotatably mounted to the first case and drivingly engaged to the shaft; and

securing a spacer to both of the pad and the adaptor.

9 . The method of claim 4 , wherein the axially moving of the first case away from the second case and relative to the shaft includes:

sliding the mobile member and the first case mounted thereto relative to the static member to separate the first case from the second case thereby creating the gap.

10 . The method of claim 4 , wherein the radially and axially supporting of the shaft through the gap includes:

mounting an intermediate shaft support to the static member of the support fixture assembly; and

connecting the intermediate shaft support to the shaft.

11 . The method of claim 10 , wherein the removing of the first case includes:

separating the mobile member of the support fixture assembly from the static member; and

moving the first case away from the second case via the mobile member.

12 . The method of claim 11 , wherein the moving of the first case includes hoisting the first case via the mobile member.

13 . The method of claim 4 , wherein the mounting of the static member of the support fixture assembly to the second case includes mounting the static member of the support fixture assembly to a flange of the second case.

14 . The method of claim 13 , wherein the static member of the support fixture assembly has a top beam and a brace secured to the top beam, the brace defining a U-shape and extending partially around the case assembly, the method including:

securing the brace to the flange of the second case.

15 . The method of claim 14 , wherein the mobile member of the support fixture assembly has a top rail, the method including:

slidably engaging the top rail of the mobile member to the top beam of the static member.

16 . The method of claim 15 , wherein the mobile member includes a forward brace and a rearward brace both secured to the top rail, the method including:

securing each of opposite flanges of the first case to a respective one of the forward brace and the rearward brace.

17 . The method of claim 4 , comprising after servicing of the aircraft engine re-installing the first case by:

slidably engaging the mobile member to the static member;

radially and axially supporting the end of the shaft with the static member;

disengaging the shaft from the static member via the gap; and

moving the first case towards the second case.

18 . The method of claim 1 , further comprising, after the removing of the first case, removing a high-pressure turbine being enclosed by the second case.

19 . The method of claim 18 , wherein the removing of the high-pressure turbine includes:

unfastening a nut threadingly engaged to a high-pressure shaft of the aircraft engine; and

pulling on the high-pressure turbine.

20 . The method of claim 19 , wherein the pulling on the high-pressure turbine includes pulling on the high-pressure turbine with an actuator.