Pratt & Whitney will not go public with the definitive data on the fuel burn and noise performance of its GTF geared turbofan demonstrator engine until the second half of this year as it has agreed with Airbus to wait until all the findings of flight-testing on the A340-600 flying testbed have been fully analysed.

Although the GTF demonstrator undertook a brief 44h flight-test campaign on P&W's Boeing 747SP testbed in mid-2008, much of the engine's detailed operational flight evaluation and data collection - including extreme flight manoeuvres and noise trials - was carried out on Airbus's A340-600 development aircraft in the final quarter of 2008. The engine flew 76h in 27 flights on the A340, and is now being returned to P&W's East Hartford, Connecticut base for strip down.

P&W is able to make public data from its ground tests and the 747 flights, but "we won't do any real briefings on the flight-test results until we've got all the A340 data analysed and we've closed with Airbus", says P&W vice-president next-generation product family Bob Saia.

Speaking at an event in Toulouse to officially mark the end of the GTF demonstrator's flight-test campaign on the A340, Saia said that "out of respect to Airbus, as this was a joint technology programme, we had agreed up front that before we would share the A340 data internally with our senior managers and with customers we'd have agreement between P&W engineers and Airbus engineers on the results".

Saia expects it will be "the latter half of this year" before P&W will go public with the results, while several airline symposia are planned "in the mid-to-latter part of 2009 to brief them on the flight-testing".

Airbus, which did not to participate in the Toulouse event held at P&W nacelle supplier Goodrich's facility, is playing down the significance of the A340 flight-tests, saying that their purpose was "to evaluate certain features (eg fan-drive gear system) of P&W's GTF technology and identify any potential challenges", but that it has "no plans to install the GTF on current products".

One of the GTF's firm airframe applications is the 110/130-seat Bombardier CSeries, which is a competitor to the smaller A320 models, and Airbus marketers have been quick to make play of the fact that the rival has yet to secure a firm order despite its launch at Farnborough last year.

Source: Flight International