Tests reveal room to improve Chapter 4 noise margin Embraer and GE Aircraft Engines have started a programme to reduce the noise of the Embraer 170 after flight-testing revealed that its compliance margin to Chapter 4 is less than anticipated.

Speaking to Flight International at last week's European Regions Airline Association general assembly in Dublin, Embraer executive vice-president commercial aircraft Fred Curado said while the aircraft meets its guarantees, "we would like the cushion to Chapter 4 to be greater". He adds that because the slightly larger 175 has a shallower climb-out profile than the 170, its compliance margin is reduced further, which has provided added impetus to the noise reduction effort.

There is also an internal noise issue, says Curado. "Subjectively, some people say the aircraft is noisy in certain parts of the cabin."

Curado says the issue goes back to the original design weight increase that the 170 underwent during the development stage, and that the manufacturer is "working with GE on airframe/engine modifications to increase and extend the compliance margin, with efforts mainly focused on the engine".

For the 175, which only recently entered flight-test, there is still the possibility that some gain could be made by tweaking flap settings to improve the climb profile, says Curado.

GE confirms that a joint team is examining ways of "fine tuning the engine on the application" and that it expects to be able to "resolve internal and external noise issues early in the programme".

Meanwhile, flight-testing of the 170 is almost complete, with around 400h of function, and reliability and maturity tests about to start. Certification is due in November ahead of first deliveries to Alitalia Express and US Airways towards the end of that month.

Embraer has signed a "commercial agreement" with German regional carrier Cirrus Airlines for a single Embraer 170. The deal is expected to be confirmed by the end of the year for delivery in December 2004.

Source: Flight International