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).
(P1.3 + P5.0)/P2.0 or P INT/P2.0
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.
Have a look here for photos
http://www.pprune.org/ubb/NonCGI/For...ML/001256.html
This is all in relation to the RB211-524G/H(T) and I'd assume the Trent 700 uses the same system.
I think your correct.
[This message has been edited by CCA (edited 21 September 2000).]