Rolls use Integrated Engine Pressure Ratio (IEPR) which uses Intake pressure (P2.0/T2.0) vs Fan exhaust (P1.3) AND Hot stream exhaust (P5.0) or P INT.
The P2 probe is at the top of the inlet.
The P1.3 probes are on the A frames, Upper left, lower right and the Interservices fairing.
The P5s are on the turbine bearing support struts.
I'll get back to you with photos.
[This message has been edited by CCA (edited 18 September 2000).]