Questo ha provocato la messa a terra di quattro dei sei prototipi del 787, che dopo controlli sono tornati in volo.

Purtroppo un evento del genere potrebbe procurare un ritardo sulla tabella di marcia del programma di consegne.

787 first delivery delayed to mid-Q1 2011
By Jon Ostrower

Boeing has confirmed a fresh delay to its 787 programme, citing compounded issues with workmanship problems with the aircraft's Alenia Aeronautica-built horizontal stabilizer and its Rolls-Royce Trent 1000 engines.

The first delivery of its 787 Dreamliner to launch customer All Nippon Airways (ANA) has now slipped to the middle of the first quarter of 2011, from the originally forecasted fourth quarter 2010.

"The delivery date revision follows an assessment of the availability of an engine needed for the final phases of flight test this fall," says Boeing.

While the airframer did not explicitly address the uncontained 2 August failure of a 'Package A' Trent 1000 in its announcement, the company says "the delivery date revision follows an assessment of the availability of an engine needed for the final phases of flight test this fall", indicating 'Package B' powerplants may be substituted for the early build Trent 1000s for ANA.

With a lack of specifics from Boeing and Rolls-Royce, the future of the Package A engine remains uncertain. However, indications exist that a modification for the failed part will be fed back into the early production engines with the fall testing related to flying Airplane Nine - the first production 787 to fly - on limited engineering tests, instead of Package B certification testing on test aircraft four.

Boeing's 787 flight test programme planned to run "another small test programme, within a flight test programme" for the Package B engines, which are slated to be test flown on the company's fourth test aircraft later this year. ZA004 is currently powered by twin Package A engines.

The Package B engines include a revised six-stage low pressure turbine (LPT) design, high-aspect-ratio blades, relocation of the intermediate-pressure (IP) compressor bleed offtake ports and fan outlet guide vanes with improved aerodynamics. The revisions will also bring fuel consumption of the powerplant within 1% of the original specification.

Guardando la certificazione ho notato che le versione E ed H hanno unadifferenza significativa di spinta rispetto alle altre versioni; per quali utilizzi sono previsti?

Brutte notizie al mio ritorno a lavoro, purtroppo.
Lo scorso 2 Agosto un modello di Trent 1000 Package A, durante un test nella bay58 a Derby, ha avuto un 'uncontained failure' dalla turbina di media pressione, causato da un esercizio a regime non appropriato.
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Compatibilmente con la riservatezza dell'argomento e considerando che sarò fuori sede ancora per un po' di tempo, cercherò di darvi notizie e rispondere alle vostre eventuali domande.

La failure porterà a ridisegnare delle parti...

Il Package B ha gia' delle parti ridisegnate proprio per ovviare al problema, soprattutto nella distribuzione delle cave di raffreddamento della pala, ma potrebbe essere necessario anche retrofittare il Package A.

Part 33 > Section 94 - Blade containment and rotor unbalance tests

(a) Except as provided in paragraph (b) of this section, it must be demonstrated by engine tests that the engine is capable of containing damage without catching fire and without failure of its mounting attachments when operated for at least 15 seconds, unless the resulting engine damage induces a self shutdown, after each of the following events:

(1) Failure of the most critical compressor or fan blade while operating at maximum permissible r.p.m. The blade failure must occur at the outermost retention groove or, for integrally-bladed rotor discs, at least 80 percent of the blade must fail.

(2) Failure of the most critical turbine blade while operating at maximum permissible r.p.m. The blade failure must occur at the outermost retention groove or, for integrally-bladed rotor discs, at least 80 percent of the blade must fail. The most critical turbine blade must be determined by considering turbine blade weight and the strength of the adjacent turbine case at case temperatures and pressures associated with operation at maximum permissible r.p.m.