firstfloor
I think at 12 quarts, the Powerplant may have been 'leaking' chronically. With the tank at 12, the system had to account for 16 quarts. As to Oil fire, the quantity remained constant prior, through, and after "fire"*. If the IT separated from the Drive Arm, it would certainly overspeed independently of the Shaft**; I think the Shaft maintained its integrity, but slipped at the Thrust area coupling, (axially).
I lean toward an engine Stall with interruption of N2 gas, the first bang, and having blown through the IPLP, and upset the IT to disintegrate, it exited the case, second bang. I kind of think the noise was approximately simultaneous, but due to the character of the reports, each was 'heard'. This is to say the Drive Arm failure caused the N2 loss, which caused the Stall, which caused the Burst, something like that.
*we cannot forget the "Stub Pipe" here. Supposedly it was pouring Oil into the HPIP Plenum, but the reads of Annex14's don't support this.
**but not for long, at least not in some orderly manner, almost immediately would blades start to depart, as they contacted the Stator Guide Vanes. The Wheel would orbit its Shaft with a larger bore radius than it started with, causing severe out of balance issues (see vib HP %RPM). The focus of stage one vibration would be the bearing space shared with HP, I feel that is why the vib was highest at the HPT.
Last edited by bearfoil; 29th December 2010 at 12:26.