Grob G 520
The Grob G 520, also known as EGRETT, is a German high-altitude, long-endurance reconnaissance aircraft built by Grob Aircraft. Only six were made: five single-seat G 520s and one G 520T twin-seat trainer. It first flew on 24 June 1987 and entered certification in 1991.
Development and purpose: The G 520 originated from a joint German Air Force–US Air Force program to create a high-altitude, long-duration surveillance platform for treaty verification and environmental monitoring. Grob built the airframe, E-Systems provided the avionics, and Garrett supplied the engine (a Honeywell TPE 331-14F). The name EGRETT reflects the three companies involved. In the US it was called Senior Guardian; in Germany, LAPAS.
Records and service: In September 1988, the D-450 EGRETT I set world records for altitude and time to climb. In the early 1990s, two pre-production EGRETT II aircraft were built. Germany ordered nine EGRETT IIs in 1992, but the program was canceled in 1993 due to defense budget cuts and political issues. Five single-seat G 520s were completed, plus one G 520T trainer.
Usage: The aircraft has been used by the German Aerospace Center and other agencies for research and niche high-altitude missions, including towing the Perlan II glider to record altitude in 2018.
Design and capabilities: The G 520 is a fully composite mid-wing aircraft with very high aspect ratio wings. It is powered by a Honeywell TPE 331-14F turboprop driving a four-blade Hartzell propeller, with mufflers to reduce noise and infrared signature. It has tricycle landing gear that retracts into wing fairings. The slim fuselage includes a central detachable payload bay (Bay 13) and 12 payload compartments for up to 850 kg of mission gear, which can include electro-optical sensors, LIDAR, SIGINT, and scientific equipment. For maritime patrol, it can carry radar or satcom gear, with an optional underbelly radome. The twin-seat G 520T seats a pilot and a sensor operator, and can be equipped with a digital glass cockpit. Refitted aircraft often have dual GPS and all-weather capabilities.
Future prospects: In the 2010s Grob proposed a modernised G 520NG with more advanced systems and the option for remote piloting, marketed as a cost-effective alternative to larger unmanned systems and not ITAR-restricted. In later years, the G 520T has been upgraded toward optionally piloted operation.
This page was last edited on 2 February 2026, at 15:08 (CET).