Narrative:

The first startup was perfectly normal; except for a 'thunk; thunk; thunk...' sound coming from forward and under us after nosewheel steering was turned on (note: this sound did not return on subsequent startups). Hydraulic systems a & B pressure were normal during the after engine start checks. When the captain released the parking brake; he almost immediately said he had no steering. He used brakes and differential power to turn the plane away from the terminal; stop; and set the parking brake. We then got the QRH out and followed the procedure with no luck. We cycled the NWS and NWS high buttons; and turned the hydraulic stby to 'continuous'; with no luck. We had alternating 'NWS failure' or 'NWS inoperative' on the cas and hydraulic page of the mfd while cycling the buttons. No indication or message about problems with the parking brake or accumulator. We then got a high-pressure reading and turned the standby pump back to auto. We shut down; exited; and called maintenance. We were told to fire up; and slowly move the rudder pedals and tiller; to try to get the nosewheel steering to engage (this is the QRH procedure). No luck--we saw an additional cas message: 'NWS power up failure'. We shut down again; called operations and were told to get some distance to taxi and try to get the nosewheel steering to engage while moving. We were towed back to where we had originally been parked. We got in; fired up the APU; and set the parking brake; and we got the blue 'P-brk' on the cas. The chocks were pulled; and we immediately started to roll. The captain and I were mashing and pumping the brakes; cycled the parking brake handle several times; and tried steering. Nothing worked; and we slowly rolled down the slope and into the fuel truck. We shut down and tried to get out of the passenger door. It fell about a quarter of the way and hit a golf cart there. We then exited through the galley door; and after seeing no fire hazard; I disconnected the batteries. Note: during both the preflight inspection and post collision inspection; the hydraulic systems external viewing gauges all showed approx 2000psi. Also; if the parking brake accumulator pressure was low we should have gotten an amber cas message and a warning chime; neither of which we got.

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Original NASA ASRS Text

Title: While trouble shooting nosewheel steering anomalies with advisories from maintenance; the flight crew of a DO-328 started engines; released the parking brake and found themselves rolling toward a fuel truck with no nosewheel steering or brakes. The aircraft was finally stopped upon encountering the truck.

Narrative: The first startup was perfectly normal; except for a 'thunk; thunk; thunk...' sound coming from forward and under us after nosewheel steering was turned on (note: this sound did not return on subsequent startups). Hydraulic systems A & B pressure were normal during the after engine start checks. When the Captain released the parking brake; he almost immediately said he had no steering. He used brakes and differential power to turn the plane away from the terminal; stop; and set the parking brake. We then got the QRH out and followed the procedure with no luck. We cycled the NWS and NWS HIGH buttons; and turned the HYD STBY to 'continuous'; with no luck. We had alternating 'NWS FAILURE' or 'NWS INOP' on the CAS and Hydraulic page of the MFD while cycling the buttons. No indication or message about problems with the parking brake or accumulator. We then got a high-pressure reading and turned the standby pump back to auto. We shut down; exited; and called maintenance. We were told to fire up; and slowly move the rudder pedals and tiller; to try to get the nosewheel steering to engage (this is the QRH procedure). No luck--we saw an additional CAS message: 'NWS PWR UP FAILURE'. We shut down again; called operations and were told to get some distance to taxi and try to get the nosewheel steering to engage while moving. We were towed back to where we had originally been parked. We got in; fired up the APU; and set the parking brake; and we got the blue 'P-BRK' on the CAS. The chocks were pulled; and we immediately started to roll. The Captain and I were mashing and pumping the brakes; cycled the parking brake handle several times; and tried steering. Nothing worked; and we slowly rolled down the slope and into the fuel truck. We shut down and tried to get out of the passenger door. It fell about a quarter of the way and hit a golf cart there. We then exited through the galley door; and after seeing no fire hazard; I disconnected the batteries. Note: during both the preflight inspection and post collision inspection; the hydraulic systems external viewing gauges all showed approx 2000psi. Also; if the parking brake accumulator pressure was low we should have gotten an amber CAS message and a warning chime; neither of which we got.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.