Probabilities
Yes Bear that is what the Bayesian Staticians and the board of Rolls Royce determined. The machine has four engines and even if one failed the probability of a second failure on the same 'plane would be improbable.
Statistics are a useful tool for so many purposes and are much beloved of the social scientists in academic circles.
I am sure Rolls Royce are waiting until the T972s are out of the news but with 32 units in service it is unlikely that this will happen. The only way they can currently prevent the engines from failing is to replace them before another event happens.
Thay can't because:
1. They just don't have enough spare engines
2. They cannot afford to borescope them after every cycle.
3. They are already committed to contracted work elsewhere.
viz. the A380 production line in Toulouse.
4. They cannot allocate resources to redesign the engine because of
new technology impending viz. the open fan designs
5. To employ radical methods to address #2 above would cause a minor
cash flow crisis. Independent aero engineers are not cheap to hire nor will they sign off anything that is unsound.
So all in all the situation will remain as it is for the forseeable future. If RR decided to follow #5 above they could or will be presented with rejection notices which would ground the aircraft. Moreover the ATSB could ground the Qantas fleet of A388s. An impass situation.
The logical solution is for RR Derby UK to suspend deliveries to the Toulose production line in France, and ask the customer to accept the EA engine instead. I am sure if the 14 members on the board of RR had the pragmatic outlook common within the global engineering industry they would enact this policy.
Last edited by DERG; 1st Mar 2011 at 08:10.