Stage III Technologies has begun developing a hushkit for the Fokker F28 to enable it to meet latest International Civil Aviation Organisation noise legislation.

The unit being developed for the F28's Rolls-Royce Spey 555 engines is based on a Stage 3 hushkit already under way for the Spey 511-powered Gulfstream II and III business jets. The new kit is expected to be certificated and available for customers by the third quarter of 1999.

Las Vegas, Nevada-based Stage III has completed initial windtunnel tests of the F28 hushkit "with extremely promising results", says president Jack Anderson. Performance penalties are expected to be no greater than the 5-7% estimated for the Gulfstream hushkit. Stage 3 limits will be met without reducing gross weight, he says.

The Gulfstream hushkit is in the final stages of ground test, with flight tests on a GII to begin in August. Stage III is now building a prototype F28 hushkit for ground tests, with flight testing to begin within nine months. Small changes are required to adapt the ejector/mixer design to the lower thrust Spey 555.

Texas-based Dallas Airmotive is marketing the hushkits, and will undertake Gulfstream and F28 kit installations. The company expects the equipment for the F28 to have around the same $1.5 million cost as a GII/III shipset.

Stage III says that the F28 project does not need data from Fokker Aviation, which has a programme under way to re-engine the twinjet.

Source: Flight International