Flight crew of an mdt air carrier aircraft lost control of the aircraft on the ramp after the wheel ...

Narrative:

While preparing the aircraft for a ferry flight from tpa to mia, prior to engine start, the aircraft rolled off the main ramp into a fence. Upon my arrival at tpa, I met the first officer and flight attendant at the gate. The aircraft was on the remote ramp (southeast corner adjacent to gate). We asked to have the aircraft towed up to the gate and were told that it had already been moved (towed) by ground personnel 3 times that day and they didn't want to move it again. We walked out to the aircraft and the first officer began a walk-around inspection and the flight attendant and I boarded the aircraft. After the first officer got on board, I asked him if he had pulled the chocks on his walk-around. His reply was 'no.' I asked him if we could normally get somebody out to the remote ramp for starting. He wasn't sure. I then instructed him to pull the chocks and we could simply start on our own and leave. He did pull the chocks and reboarded. We were doing our 'flows' and preparing the cockpit for the checklists when the aircraft started slowly rolling backwards. We both applied our brake pedals and I grabbed the park brake to ensure it was engaged. The aircraft rolled off the ramp and down a grassy slope and into a fence where it came to rest. The type aircraft (dhc-8) has an accumulator to keep #2 system hydraulic pressure available to the parking brake. This is limited to approximately 3 applications. Each time the aircraft had been moved by the ground personnel the releasing and resetting of the park brake had depleted the pressure in the accumulator, so there was no pressure available to the parking brake. Also, in that I had not told the first officer that this was the first flight of the day for this aircraft. He only did a cursory walk-around and not a full preflight inspection that would have directed his attention to an accumulator gage in the right wheel nacelle. Had we gotten to the point of running our before STAR (originating) checklist, we would have seen that we were below the minimum park brake pressure for starting (1500 psi) but the aircraft started rolling before we had a chance.

Original NASA ASRS Text

Title: FLC OF AN MDT ACR ACFT LOST CTL OF THE ACFT ON THE RAMP AFTER THE WHEEL CHOCKS WERE PULLED BEFORE STARTING THE ENGS, RESULTING IN THE ACFT ROLLING UNTIL IT HIT A FENCE WHERE IT CAME TO A STOP UNDAMAGED. THERE WERE NO PAX ABOARD!

Narrative: WHILE PREPARING THE ACFT FOR A FERRY FLT FROM TPA TO MIA, PRIOR TO ENG START, THE ACFT ROLLED OFF THE MAIN RAMP INTO A FENCE. UPON MY ARR AT TPA, I MET THE FO AND FLT ATTENDANT AT THE GATE. THE ACFT WAS ON THE REMOTE RAMP (SE CORNER ADJACENT TO GATE). WE ASKED TO HAVE THE ACFT TOWED UP TO THE GATE AND WERE TOLD THAT IT HAD ALREADY BEEN MOVED (TOWED) BY GND PERSONNEL 3 TIMES THAT DAY AND THEY DIDN'T WANT TO MOVE IT AGAIN. WE WALKED OUT TO THE ACFT AND THE FO BEGAN A WALK-AROUND INSPECTION AND THE FA AND I BOARDED THE ACFT. AFTER THE FO GOT ON BOARD, I ASKED HIM IF HE HAD PULLED THE CHOCKS ON HIS WALK-AROUND. HIS REPLY WAS 'NO.' I ASKED HIM IF WE COULD NORMALLY GET SOMEBODY OUT TO THE REMOTE RAMP FOR STARTING. HE WASN'T SURE. I THEN INSTRUCTED HIM TO PULL THE CHOCKS AND WE COULD SIMPLY START ON OUR OWN AND LEAVE. HE DID PULL THE CHOCKS AND REBOARDED. WE WERE DOING OUR 'FLOWS' AND PREPARING THE COCKPIT FOR THE CHKLISTS WHEN THE ACFT STARTED SLOWLY ROLLING BACKWARDS. WE BOTH APPLIED OUR BRAKE PEDALS AND I GRABBED THE PARK BRAKE TO ENSURE IT WAS ENGAGED. THE ACFT ROLLED OFF THE RAMP AND DOWN A GRASSY SLOPE AND INTO A FENCE WHERE IT CAME TO REST. THE TYPE ACFT (DHC-8) HAS AN ACCUMULATOR TO KEEP #2 SYS HYD PRESSURE AVAILABLE TO THE PARKING BRAKE. THIS IS LIMITED TO APPROX 3 APPLICATIONS. EACH TIME THE ACFT HAD BEEN MOVED BY THE GND PERSONNEL THE RELEASING AND RESETTING OF THE PARK BRAKE HAD DEPLETED THE PRESSURE IN THE ACCUMULATOR, SO THERE WAS NO PRESSURE AVAILABLE TO THE PARKING BRAKE. ALSO, IN THAT I HAD NOT TOLD THE FO THAT THIS WAS THE FIRST FLT OF THE DAY FOR THIS ACFT. HE ONLY DID A CURSORY WALK-AROUND AND NOT A FULL PREFLT INSPECTION THAT WOULD HAVE DIRECTED HIS ATTENTION TO AN ACCUMULATOR GAGE IN THE R WHEEL NACELLE. HAD WE GOTTEN TO THE POINT OF RUNNING OUR BEFORE STAR (ORIGINATING) CHKLIST, WE WOULD HAVE SEEN THAT WE WERE BELOW THE MINIMUM PARK BRAKE PRESSURE FOR STARTING (1500 PSI) BUT THE ACFT STARTED ROLLING BEFORE WE HAD A CHANCE.

Data retrieved from NASA's ASRS site as of July 2007 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.

Attributes
ACN	267232
Time
Date	199403
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : tpa
State Reference	FL
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Navigation In Use	Other Other
Flight Phase	ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 6300 flight time type : 4000
ASRS Report	267232
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Flight crew of an mdt air carrier aircraft lost control of the aircraft on the ramp after the wheel chocks were pulled before starting the engines, resulting in the aircraft rolling until it hit a fence where it came to a stop undamaged. There were no passenger aboard!