CAPT OF AN ATR42 FEATHERED BOTH PROPS JUST BEFORE COMPLETING A STOP DURING PARKING RESULTING IN RUNNING INTO A GND PWR UNIT WHEN ALL BRAKE PRESSURE WAS LOST DUE TO THE FEATHERED PROPS. THERE WAS ONLY MINOR DAMAGE TO THE NOSE CONE.

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WAS TAXIING TO PARKING IN OKC. I WAS ALMOST TO A STOP WITH #1 ENG SHUT DOWN WHEN I FEATHERED #2 PROP. I HAD BRAKE PRESSURE AT THAT TIME TO STOP HEAD-ON. THEN MARSHALLER STARTED RUNNING BACKWARDS AND SIGNALING A R TURN. I ALLOWED THE ACFT TO TURN AND RELEASED BRAKE PRESSURE. WHEN SIGNALED TO 'PANIC STOP' WE HAD NO BRAKES. DUE TO CLOSE PROX OF GPU; 4-5 FT; WE HIT IT. HITTING GPU WAS UNAVOIDABLE DUE TO POS OF EQUIP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT THE REASON THAT HE DID NOT HAVE ANY BRAKE PRESSURE WITH WHICH TO STOP THE ACFT WAS DUE TO THE FACT THAT HE HAD THE L ENG ALREADY SHUT DOWN AND HE HAD JUST FEATHERED THE R PROP. THIS ACTION CAUSED THE COMPLETE LOSS OF ALL HYD PRESSURE SINCE BOTH PUMPS ARE DRIVEN BY THE PROPS TURNING. THERE IS AN EMER ELECTRIC DRIVEN PUMP TO USE FOR THE GEAR AND EMER BRAKING ONLY. HE SAID THAT HE KNEW AT ONCE WHY HE HAD NO BRAKE; BUT IT WAS TOO LATE. HE FURTHER STATED THAT THE COMPANY HAS HAD OTHER SIMILAR INCIDENTS BUT THAT THERE HAD BEEN NO ALERT NOTICES ISSUED OF THE INCIDENTS BY THE COMPANY THROUGH WHICH OTHER PLTS COULD LEARN BY OTHER PLT EXPERIENCES. THE ACFT WAS AN ATR42.