California-based AEVEX Aerospace has amended its existing FAA STC currently approved for the DHC-6-300 series to include the DHC-6-400 series Twin Otter series aircraft. This new product allows the DHC-6-400 series to operate in the Standard Commuter Category with increased maximum take off weight of 14,000lbs (6,350 Kg) when equipped with a Garmin G950 NXi/G1000NXi avionics suite.

"Our DHC-6-400HG STC will transform the DHC-6-400 series by combining a significant increase in payload capabilities with the latest Garmin G950NXi/G1000NXi integrated avionics systems," says VP of advanced solutions John Zublin. "The collective package allows operators to expand their mission role, optimise payload and range and add value to their aircraft while increasing revenues. We are collaborating with Aerocorp Avionics to take the DHC-6-400 series to a new level of capability by also incorporating the latest Garmin features of their GFC 700 three axis autopilot."

Aerocorp director of maintenance Joshua Fox adds: "The Garmin GFC 700 is an AHRS-based automatic flight control system providing flight director, yaw damper, automatic and manual electric trim capabilities, for a high level of precision digital control and crisp autopilot controllability. The availability of a Garmin G950NXi/G1000NXi cockpit for DHC-6-400 operators around the world is a welcome option to improve functionality and supports smooth transition for pilots moving up from trainers into the regional airlines."

The DHC-6-300HG STC increases the payload capabilities of the basic DHC-6-300 Twin Otter series aircraft from 12,500 lbs (5,670 kg) MTOW to 14,000 lbs (6,350 kg), providing an increase of 1,500 lbs (680 kg), or 12 per cent overall, and represents a 31 per cent increase in payload based on an average empty weight of 7,700 lbs. Operations are allowed to the full 750 shp of the PT6A-34 engines along with the improved efficiency and noise reduction of the Hartzell four blade Scimitar propellers. Additional aerodynamic and structural enhancements complete the modifications. As a Standard Commuter Category STC, DHC-6-300 and DHC-6-400 operators' area able to operate in revenue service without special purpose restrictions.

The Garmin G950NXi/G1000NXi navigation capabilities include Required Navigation Performance features with integrated radio modules providing VHF Comm/Nav, ILS and WAAS/SBAS-certified GPS, and LPV approaches meeting NextGen ADS-B Out regulatory requirements.