20110214002129I

Nearing the completion of a production test flight, the aircraft was established inside the final approach fix for runway 30. With flaps set to 20 degrees, the crew extended the landing gear. Shortly thereafter, the "left hydraulic quantity low" annunciator illuminated. The crew selected the hydraulic synoptic page and noticed that the left system hydraulic quantity was decreasing. Next, the "left hydraulic system fail" annunciator illuminated. Since the aircraft was already in a landing configuration below 1,000 feet AGL, the captain elected to continue the approach to a landing. The crew stated that since the auxiliary hydraulic system reservoir still contained fluid and that the emergency/parking brake accumulator was charged to 3,000 PSI, the expectation was to have full hydraulic system capability except for left engine thrust reverse after landing. Upon touchdown, however, the captain discovered that normal braking was inoperative. Because of the possibility of tire blowout (no anti-skid capability), the captain stated that he did not utilize the emergency brakes. With approximately 3,000 feet of runway remaining, the captain initiated a go around by advancing the throttles to takeoff power. The first officer, who felt that the aircraft was not sufficienly accelerating to effect a safe takeoff, retarded the throttles to idle. The aircraft departed the departure end of runway 30 while traveling at 95 knots. The aircraft came to a stop approximately 2,000 feet off the runway end and slightly right of the extended runway centerline. The left main landing gear collapsed. All three occupants exited the aircraft through the main cabin entry door. The investigation showed that upon landing gear extension, the nose landing gear swivel assembly cracked which allowed the left and auxiliary system hydraulic fluid to be pumped overboard. When the crew was first made aware of the problem on final approach to runway 30, the auxiliary hydraulic system reservoir still contained fluid and should have allowed for normal braking capability upon landing. However, in the relatively short period of time between said discovery and touchdown, the remaining auxiliary reservoir fluid was pumped overboard which rendered the normal brakes inoperative. According to the Gulfstream G550 "left system and auxiliary hydraulic system loss of fluid" checklist, the aircraft should be landed on a runway that is at least 7,000 feet long and 150 feet wide with a crosswind component of less than 5 knots. The airplane can then be brought to a stop with the use of right thrust reverse, speed brakes, and the application of emergency brakes. Runway 30 at atw is 6501 feet long by 150 feet wide and the wind at the time of this incident was 340 degrees at 10 knots.