A B777, while being towed, incurred damage to the nose gear when a right turn was attempted.

Attributes
ACN	573001
Time
Date	200302
Day	Sat
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 125 flight time total : 11000 flight time type : 1010
ASRS Report	573001
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical ground encounters other maintenance problem : improper maintenance non adherence : published procedure non adherence : far other anomaly
Independent Detector	other other : person 3
Resolutory Action	none taken : detected after the fact
Consequence	other other other Other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : non compliance with legal requirements
Supplementary
Problem Areas	Flight Crew Human Performance Maintenance Human Performance Company Aircraft
Primary Problem	Maintenance Human Performance

Narrative:

Aircraft was being towed from maintenance to engine start-up point. As the tug started to make a right turn, there was a loud bang. Immediately applied brakes and stopped the aircraft before it went off taxiway. Tug driver immediately called for brakes to be applied after loud bang. The tow bar ripped the nose gear towing assembly from the nose gear. Aircraft ran over the tow bar. 2 nose tires had to be replaced. The steering bypass pin appeared to be in with red flag showing. Tug driver was operating at a normal speed, estimate at about 5 KTS. Nose gear steering check ok. Mission departed several hours later. No problems.

Original NASA ASRS Text

Title: A B777, WHILE BEING TOWED, INCURRED DAMAGE TO THE NOSE GEAR WHEN A R TURN WAS ATTEMPTED.

Narrative: ACFT WAS BEING TOWED FROM MAINT TO ENG START-UP POINT. AS THE TUG STARTED TO MAKE A R TURN, THERE WAS A LOUD BANG. IMMEDIATELY APPLIED BRAKES AND STOPPED THE ACFT BEFORE IT WENT OFF TXWY. TUG DRIVER IMMEDIATELY CALLED FOR BRAKES TO BE APPLIED AFTER LOUD BANG. THE TOW BAR RIPPED THE NOSE GEAR TOWING ASSEMBLY FROM THE NOSE GEAR. ACFT RAN OVER THE TOW BAR. 2 NOSE TIRES HAD TO BE REPLACED. THE STEERING BYPASS PIN APPEARED TO BE IN WITH RED FLAG SHOWING. TUG DRIVER WAS OPERATING AT A NORMAL SPD, ESTIMATE AT ABOUT 5 KTS. NOSE GEAR STEERING CHK OK. MISSION DEPARTED SEVERAL HRS LATER. NO PROBS.

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.