WHATEVER THE virtues of the Lockheed C-130 Hercules, cabin quietness is not one of them. Now GEC-Marconi Avionics plans to do something about it.

The UK company began trials of an active noise-control system on a US Air National Guard C-130H late in 1995.

Active noise control is already being offered on several civil turboprop airliners, but this is believed to be the first time that the system has been tried on either a military or a four-engined aircraft.

The trials took place following a competition held by Lockheed Martin in 1995. GEC plans to continue the test work throughout most of this year, after which a decision will be made on whether to offer the equipment as an option on new C-130Js and as a retrofit on existing models. o

The Hercules is notorious for noise on the flightdeck and the maindeck. GEC-Marconi says that tests have shown their system, which uses frequency-domain algorithm techniques to cancel out the noise, has shown improvements, particularly on the flightdeck. The GEC-Marconi unit has already been selected as an option on the Aero International (Regional) Jetstream J41. Certification is scheduled at the end of March, with first deliveries planned for the third quarter.

Source: Flight International