AUS FEDERAL AVIATION Administration special report recommends design changes, additional flight restrictions and more flight testing as part of an effort to reduce Robinson Helicopter R22 and R44 accidents.

The report stops short of accepting a recommendation from the US National Transportation Safety Board to ground the two-seat R22 and four-seat R44 light piston-engine helicopters. It urges additional measures, which are designed to increase safety, however.

The panel recommends an improved rotor-speed control, to reduce the likelihood that the main-rotor blades will stall. It wants the low-rotor-speed warning horn, to activate sooner, giving pilots more time to respond, to an impending rotor RPM decay.

It also advocates an airworthiness directive that bars low-g pushover manoeuvres during training. Another change would prohibit flight with the RPM governor turned off except for training.

Source: Flight International