Pilatus Britten-Norman (PBN) is planning to offer as an option a silencer developed by German Islander operator Luftverkehr Friesland of Harle (LFH) and designer Hermann Liese to meet stringent 85dB noise regulations in the the country, cutting noise signatures by up to 11dB.
LFH president and chief pilot Jan Bruzema says that the 4kg Liese silencers fitted to the Textron Lycoming flat-six engine exhausts on its three PBN BN-2s reduce noise by 9.8dB, with no loss of power, and that a further improvement to 11dB will come early in 1998 when four-bladed propellers are fitted, because of increased tip clearance from the fuselage.
German regulatory approval was given in November 1996 for the 185kW (250hp)version of the Islander and in July 1997 for the 225kW version. Certification in the USA and Canada is scheduled "one to two months from now", while UK approval is expected at the "end of January", says Bruzema.
PBN says that a trial installation with the Northumberland Police in the UK will start this month as the basis for Civil Aviation Authority certification, while LFH is also "holding talks" with Isles of Scilly Skybus, which operates three Islanders.
LFH offers the installation at £5,600 ($9,200) per aircraft.
Source: Flight International
