The Grob G 520 ‘EGRETT’ (former Grob/E-Systems/AlliedSignal Egrett – its name is derived from the three companies involved in its design: E-Systems, Grob Aircraft, and Garrett, the latter firm later changing its name to AlliedSignal) is a surveillance aircraft developed in Germany in the 1980s by an international partnership.
It was intended to fill a joint German Air Force – US Air Force requirement for a high-altitude, long-duration surveillance platform for treaty verification and environmental monitoring.
Known as "LAPAS" (Luftgestütztes, abstandsfähiges Primär-Aufklärungssystem, engl: airborne, long distance primary reconnaissance system) in Germany and "Senior Guardian" in the US, the program initially attempted to acquire the Lockheed TR-1 (U-2) for this role, but when this did not succeed, a new aircraft was sought.

The initial D-450 EGRETT I development aircraft flew in 1987, and in September the following year set a class altitude record of 16,329.35 m (53,573.96 ft).
Two pre-production machines followed in 1989 and 1990 as the D-500 EGRETT II and then fitted out to the finalized G 520 design in 1991.
These latter two aircraft were owned by E-Systems and Grob respectively, and used for promotional purposes: E-Systems' for various sensor packages, and Grob's (renamed the Strato 1) to market the design to civil authorities as a resource management platform.

In 1992, the German Air Force placed an order for production of nine EGRETT IIs, to be supplemented by G 520T two-seat trainer and one of the demonstrators.
However, in February 1993, before much production had taken place, the whole program was cancelled when Eastern Europe ceased to be perceived as a threat.
The two-seater-version G 520T was completed and sold to Airborne Research Australia in Adelaide.
In 2014, Grob Aircraft repurchased the G 520T and flew it back to Germany.
The repainted aircraft will be presented to the public during the Farnborough Airshow 2014, simultaneously as kick-off for resuming the production of the G 520T.
The G 520 is a several world record holder as of 2014.
This aircraft established three world records for altitude, time to climb  in 1988.
In addition, it was the first composite aircraft specifically designed for stratospheric research and reached a record altitude of 53,573.96 feet (16.329,35 meters).

Time to climb to 15,000 meters: 40 minutes 47 seconds
Altitude in horizontal flight: 16,238.55 meters (53,276.09 feet)
Altitude without payload: 16,329.35 meters (53,573.96 feet)
The Grob G 520 ‘EGRETT’ (former Grob/E-Systems/AlliedSignal Egrett – its name is derived from the three companies involved in its design: E-Systems, Grob Aircraft, and Garrett, the latter firm later changing its name to AlliedSignal) is a surveillance aircraft developed in Germany in the 1980s by an international partnership. It was intended to fill a joint German Air Force – US Air Force requirement for a high-altitude, long-duration surveillance platform for treaty verification and environmental monitoring. Known as "LAPAS" (Luftgestütztes, abstandsfähiges Primär-Aufklärungssystem, engl: airborne, long distance primary reconnaissance system) in Germany and "Senior Guardian" in the US, the program initially attempted to acquire the Lockheed TR-1 (U-2) for this role, but when this did not succeed, a new aircraft was sought.
The initial D-450 EGRETT I development aircraft flew in 1987, and in September the following year set a class altitude record of 16,329.35 m (53,573.96 ft). Two pre-production machines followed in 1989 and 1990 as the D-500 EGRETT II and then fitted out to the finalized G 520 design in 1991. These latter two aircraft were owned by E-Systems and Grob respectively, and used for promotional purposes: E-Systems' for various sensor packages, and Grob's (renamed the Strato 1) to market the design to civil authorities as a resource management platform.
In 1992, the German Air Force placed an order for production of nine EGRETT IIs, to be supplemented by G 520T two-seat trainer and one of the demonstrators. However, in February 1993, before much production had taken place, the whole program was cancelled when Eastern Europe ceased to be perceived as a threat. The two-seater-version G 520T was completed and sold to Airborne Research Australia in Adelaide. In 2014, Grob Aircraft repurchased the G 520T and flew it back to Germany. The repainted aircraft will be presented to the public during the Farnborough Airshow 2014, simultaneously as kick-off for resuming the production of the G 520T.
The G 520 is a several world record holder as of 2014. This aircraft established three world records for altitude, time to climb  in 1988. In addition, it was the first composite aircraft specifically designed for stratospheric research and reached a record altitude of 53,573.96 feet (16.329,35 meters).
Time to climb to 15,000 meters: 40 minutes 47 seconds
Altitude in horizontal flight: 16,238.55 meters (53,276.09 feet)
Altitude without payload: 16,329.35 meters (53,573.96 feet)
Grob G 520