An A320 had parking brake set after pushback pressures check ok. Tow bar disconnected; steering pin ...

Attributes
ACN	700987
Time
Date	200606
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	ground : pushback
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 230 flight time total : 15500 flight time type : 800
ASRS Report	700987
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical other anomaly
Independent Detector	other other : 3
Resolutory Action	flight crew : regained aircraft control none taken : anomaly accepted
Consequence	other other
Supplementary
Problem Areas	Flight Crew Human Performance Maintenance Human Performance Aircraft Environmental Factor
Primary Problem	Aircraft

Narrative:

Brakes set normally after pushback/pressures checked ok. As soon as tow bar disconnected and nosewheel steering pin pulled; the aircraft started rolling forward. Ground crew called on headset that aircraft was rolling. Captain applied brakes with pedals followed by first officer. Did not notice brake pressures at the time. Aircraft continued to roll forward about 10 ft parking brake cycled on-off-on with no help. When anti-skid/nosewheel steering switch turned to the 'on' position (with brake pedals applied) the brakes immediately applied and the aircraft stopped. No injuries to flight attendants/ground personnel/or equipment. Aircraft returned to the gate with what appeared to be normal steering and brakes. Callback conversation with reporter revealed the following information: the reporter stated when the ground crew advised the flight crew the airplane was rolling the brakes were applied and the aircraft continued to roll; brakes were cycled no help. Anti-skid nose steering switch turned to 'on' and with brakes already applied the aircraft stopped. A contract technician was called and the technician arrived and advised the captain of having previous experience with A320 equipment. The brake problem was reported by the contract technician to the maintenance controller and a brake system test and check was accomplished and the system checked ok. The airplane was dispatched after maintenance and operated the remainder of the day with no parking brake problems.

Original NASA ASRS Text

Title: AN A320 HAD PARKING BRAKE SET AFTER PUSHBACK PRESSURES CHK OK. TOW BAR DISCONNECTED; STEERING PIN PULLED. THE ACFT ROLLED FORWARD; BRAKES APPLIED NO HELP. ANTI-SKID NOSE STEERING SWITCHED 'ON' ACFT STOPPED.

Narrative: BRAKES SET NORMALLY AFTER PUSHBACK/PRESSURES CHKED OK. AS SOON AS TOW BAR DISCONNECTED AND NOSEWHEEL STEERING PIN PULLED; THE ACFT STARTED ROLLING FORWARD. GND CREW CALLED ON HEADSET THAT ACFT WAS ROLLING. CAPT APPLIED BRAKES WITH PEDALS FOLLOWED BY FO. DID NOT NOTICE BRAKE PRESSURES AT THE TIME. ACFT CONTINUED TO ROLL FORWARD ABOUT 10 FT PARKING BRAKE CYCLED ON-OFF-ON WITH NO HELP. WHEN ANTI-SKID/NOSEWHEEL STEERING SWITCH TURNED TO THE 'ON' POS (WITH BRAKE PEDALS APPLIED) THE BRAKES IMMEDIATELY APPLIED AND THE ACFT STOPPED. NO INJURIES TO FLT ATTENDANTS/GND PERSONNEL/OR EQUIP. ACFT RETURNED TO THE GATE WITH WHAT APPEARED TO BE NORMAL STEERING AND BRAKES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED WHEN THE GND CREW ADVISED THE FLT CREW THE AIRPLANE WAS ROLLING THE BRAKES WERE APPLIED AND THE ACFT CONTINUED TO ROLL; BRAKES WERE CYCLED NO HELP. ANTI-SKID NOSE STEERING SWITCH TURNED TO 'ON' AND WITH BRAKES ALREADY APPLIED THE ACFT STOPPED. A CONTRACT TECHNICIAN WAS CALLED AND THE TECHNICIAN ARRIVED AND ADVISED THE CAPT OF HAVING PREVIOUS EXPERIENCE WITH A320 EQUIP. THE BRAKE PROB WAS RPTED BY THE CONTRACT TECHNICIAN TO THE MAINT CTLR AND A BRAKE SYS TEST AND CHK WAS ACCOMPLISHED AND THE SYS CHKED OK. THE AIRPLANE WAS DISPATCHED AFTER MAINT AND OPERATED THE REMAINDER OF THE DAY WITH NO PARKING BRAKE PROBS.

Data retrieved from NASA's ASRS site as of January 2009 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.

An A320 had parking brake set after pushback pressures check ok. Tow bar disconnected; steering pin pulled. The aircraft rolled forward; brakes applied no help. Anti-skid nose steering switched 'on' aircraft stopped.