An airbus flight crew reported their aircraft becoming detached from a tug while being repositioned ...

Narrative:

Parking at phx; marshaller requested to push aircraft back; tow bar unhooked from aircraft; aircraft struck a catering truck.while taxiing in at kphx; stopped on 'M' line; tug and cart in safety zone; marshaled in at wands crossed set park brake; seat belt sign 'off'; engine 1 master 'off'. Unintelligible hand signals?? I 'capt.' requested intercom communications; no response; called ramp tower; they had no information. Marshaller indicated he wanted to hook-up tug and push aircraft back. Tug driven into position; under aircraft nose out of line of sight. Release brakes hand signal given/received; I released park brake. Began push back I thought they would push back 2/3 feet. Lots of hand waving by ground personal. Aircraft seemed to be rolling back on its own; I applied brakes & stopped aircraft; set park brake. I looked back over my left shoulder and saw a catering truck behind the left wing. Called ramp and requested a supervisor and chief pilot showed-up about 15 minutes later. Maintenance personal came on board. Chief pilot escorted the first officer and myself to drug testing. Later that evening I realized I had not entered a write-up in the aml.

Original NASA ASRS Text

Title: An Airbus flight crew reported their aircraft becoming detached from a tug while being repositioned at the arrival gate. This resulted in contact with a catering vehicle; causing minor damage; before the brakes were applied. Also; they reported injury to a standing passenger due to abrupt braking.

Narrative: Parking at PHX; marshaller requested to push aircraft back; tow bar unhooked from aircraft; aircraft struck a catering truck.While taxiing in at KPHX; stopped on 'M' line; tug and cart in safety zone; marshaled in at wands crossed set Park brake; Seat belt sign 'OFF'; ENG 1 master 'OFF'. Unintelligible hand signals?? I 'Capt.' requested intercom communications; no response; called ramp tower; they had no information. Marshaller indicated he wanted to hook-up tug and push aircraft back. Tug driven into position; under aircraft nose out of line of sight. Release brakes hand signal given/received; I released Park brake. Began push back I thought they would push back 2/3 feet. Lots of hand waving by ground personal. Aircraft seemed to be rolling back on its own; I applied brakes & stopped aircraft; set Park Brake. I looked back over my left shoulder and saw a catering truck behind the left wing. Called Ramp and requested a Supervisor and Chief Pilot showed-up about 15 minutes later. Maintenance personal came on board. Chief Pilot escorted the First Officer and myself to drug testing. Later that evening I realized I had not entered a write-up in the AML.

Data retrieved from NASA's ASRS site 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	1365914
Time
Date	201606
Local Time Of Day	0601-1200
Place
Locale Reference	PHX.Airport
State Reference	AZ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural Published Material / Policy Ground Event / Encounter Vehicle

An airbus flight crew reported their aircraft becoming detached from a tug while being repositioned at the arrival gate. This resulted in contact with a catering vehicle; causing minor damage; before the brakes were applied. Also; they reported injury to a standing passenger due to abrupt braking.