Today the AAIB issued a new
Special Bulletin, updating information of previous reports.
Of note:
- No evidence of:
. EMI
. Core Engine Icing
. Bird Strike
. Wake Vortex
. Fuel Contamination
- Actual EPR values: Left 1.03 EPR, Right 1.02 EPR.
- Reduced Fuel flow was detected (could be previously inferred, since the previous report stated that the EEC "reacted" to reduced fuel flow)
- Flow stayed low after FMV was fully open (refuting "low-energy fuel" and "foaming fuel" theories)
- Spar valves operated correctly (previously only stated that they had not been operated by the crew, before the accident)
- The cavitation damage on the high-pressure pumps was
fresh (I consider this the most interesting new information)
- No recommendations by either AAIB, Boeing or RR.
Findings so far
- Cause of low engine thrust: low fuel flow
- Cause of low fuel flow: Not the faintest clue.
The upshot: complex test rigs are used at Boeing and Rolls-Royce to recreate the conditions of the flight and hopefully stumble upon something useful.
Data recordings of this and other flights are being examined statistically in the hope of finding unusual parameter combinations, since all parameters by themselves appear to be well within the operating envelope of the aircraft.
Bernd