Air carrier large transport aircraft rolled into tug after towbar disconnect.

Attributes
ACN	212868
Time
Date	199206
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sfo
State Reference	CA
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	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	ground : parked ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 180 flight time total : 12000 flight time type : 6500
ASRS Report	212868
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : commercial pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 4000 flight time type : 2100
ASRS Report	213125
Events
Anomaly	conflict : ground less severe other anomaly other
Independent Detector	other flight crewa other other : unspecified
Resolutory Action	other
Consequence	other Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

After the pushback/engine start/towbar disconnect sequence was complete the aircraft rolled forward and the lower, forward fuselage of the aircraft made contact with the top of the tug. This happened because the aircraft brakes had not been set prior to towbar disconnect. Normal procedures call for the tug driver to give the 'set brakes' instruction to the captain prior to disconnecting the towbar. To the best of the flight crew's recollection, this instruction was not given nor was it acknowledged by the captain. The flight crew and the tug driver were distracted from the normal sequence of events and procedures because during the pushback the #2 engine did not light off on the first attempt. The #2 engine was motored to clear excess fuel and then allowed to spin down while the #1 and #3 engines were started. #2 engine was then successfully started on the second attempt. The first indication the flight crew had of the problem was the sound of the collision. No one was injured.

Original NASA ASRS Text

Title: ACR LGT ACFT ROLLED INTO TUG AFTER TOWBAR DISCONNECT.

Narrative: AFTER THE PUSHBACK/ENG START/TOWBAR DISCONNECT SEQUENCE WAS COMPLETE THE ACFT ROLLED FORWARD AND THE LOWER, FORWARD FUSELAGE OF THE ACFT MADE CONTACT WITH THE TOP OF THE TUG. THIS HAPPENED BECAUSE THE ACFT BRAKES HAD NOT BEEN SET PRIOR TO TOWBAR DISCONNECT. NORMAL PROCS CALL FOR THE TUG DRIVER TO GIVE THE 'SET BRAKES' INSTRUCTION TO THE CAPT PRIOR TO DISCONNECTING THE TOWBAR. TO THE BEST OF THE FLC'S RECOLLECTION, THIS INSTRUCTION WAS NOT GIVEN NOR WAS IT ACKNOWLEDGED BY THE CAPT. THE FLC AND THE TUG DRIVER WERE DISTRACTED FROM THE NORMAL SEQUENCE OF EVENTS AND PROCS BECAUSE DURING THE PUSHBACK THE #2 ENG DID NOT LIGHT OFF ON THE FIRST ATTEMPT. THE #2 ENG WAS MOTORED TO CLR EXCESS FUEL AND THEN ALLOWED TO SPIN DOWN WHILE THE #1 AND #3 ENGS WERE STARTED. #2 ENG WAS THEN SUCCESSFULLY STARTED ON THE SECOND ATTEMPT. THE FIRST INDICATION THE FLC HAD OF THE PROBLEM WAS THE SOUND OF THE COLLISION. NO ONE WAS INJURED.

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.