- Joined
- Jun 2, 2002
- Messages
- 4,203
The blade roots have a coating of copper-nickel-indium on the pressure faces. This sacrificial material prevents blade-to-disk contact. The visual inspection that occurs routinely at blade re-lube includes verifying the amount of Cu-Ni-In remaining. I can't quote off the top of my head but rarely is it allowed to have more than 10% of this coating missing.
By reapplying the molydag you are extending the service life of both the disk and the blade. Cu-Ni-In is applied at manufacture and overhaul and Molydag 254 is also applied during manufacture and overhaul. When new the Molydag is cured in an oven in order to ensure proper bonding. Routine maintenance affords only that the Molydag be brushed on and air dry at predetermined intervals such as every 100 cycles.
Another twist to this whole cycle is that once the blade slot dove tails on the disk become excessively worn they will broach the slots and then use shims to take up the slack.
The condition of the Southwest engine will likely never be disclosed. I do know that they turn an incredible amount of cycles on their engines. An AD will be issued very soon for further root inspection of these blades. Southwest just happens to have the highest level of exposure. No matter what the media spills about this you can be assured that this airline plays by the book and does their due diligence at keeping the fleet up to date.
By reapplying the molydag you are extending the service life of both the disk and the blade. Cu-Ni-In is applied at manufacture and overhaul and Molydag 254 is also applied during manufacture and overhaul. When new the Molydag is cured in an oven in order to ensure proper bonding. Routine maintenance affords only that the Molydag be brushed on and air dry at predetermined intervals such as every 100 cycles.
Another twist to this whole cycle is that once the blade slot dove tails on the disk become excessively worn they will broach the slots and then use shims to take up the slack.
The condition of the Southwest engine will likely never be disclosed. I do know that they turn an incredible amount of cycles on their engines. An AD will be issued very soon for further root inspection of these blades. Southwest just happens to have the highest level of exposure. No matter what the media spills about this you can be assured that this airline plays by the book and does their due diligence at keeping the fleet up to date.