TRIDAIR HELICOPTERS, the California-based developer of the modified twin-engined Bell 206L-1/3/4 (known as the Gemini ST), plans to certificate it for in-flight starting of the second engine in 1996.

The modification will allow pilots to take off using one of the helicopter's two engines and then start up the second engine later on during the flight, a procedure now limited to emergencies.

Tridair president Doug Daigle says: "The aircraft will be certificated with normal procedures to allow an engine to be started in-flight. We'll make it foolproof by installing Allison 250-C22 engines which have FADEC [full-authority digital engine-control]."

Bell Helicopter, which produces licence-made 206L-4 TwinRangers using the Gemini concept, says meanwhile that it has no plans to follow Tridair in seeking single-engined certification of the TwinRanger.

Daigle says: "Basically, we have agreed to disagree with Bell."

Tridair's Gemini ST gained single-engined Category A operation twin certification of the helicopter in 1994 after Washington-based Soloy made further tests and changes to the combining gearbox at the heart of the conversion.

The US Federal Aviation Administration is expected to grant single-pilot instrument-flight-rules certification by early April. This now extends the normal operating range of the helicopter by 740km (400nm), or provides the ability to complete a flight in the event of one engine failing.

Source: Flight International