B737-800
Maintenance Airframe; Maintenance Powerplant
Maintenance Technician 42
Situational Awareness; Other / Unknown; Communication Breakdown
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Vehicle
Aircraft Aircraft Damaged; General Maintenance Action
Procedure; Staffing; Human Factors; Company Policy; Aircraft
While getting ready to push back from gate; I called for jet bridge pull [retracted] which was done.  Then waited upon Food Caterer X to move their truck which was at the aft left door of the aircraft; de-catering the aircraft.  I could not pick up the aircraft while a truck is catering; or de-catering with the Goldhofer Tractor [Tug].  After the catering truck backed out and I could see the truck off my left wing; I picked up the aircraft.  I called my Brake Rider [Flight deck] to release the brakes and turn on the anti-collision light.  I then called Ground Control for pushback clearance. Ground Control said 'clear to push onto Alpha.' I put tractor into drive and started my push until I felt something.  I pulled back into the gate a little and then went back to see what was there and saw the catering truck on its side.  I called Ground Control again to get Airfield Safety to us. It seems that another [one of] Food Caterer X's truck had parked behind the aircraft and being in the tractor and the lighting I did not see the truck.  Why they parked behind the aircraft I don't know.  However I had the aircraft anti-collision light on and strobes on the Goldhofer [Tug] and numerous other lights on the tractor. [Recommend] don't park behind aircraft.
Reporter stated they move most of their aircraft with the Goldhofer High-Speed Towbarless Tractor tug when towing aircraft. Goldhofer Tractors are used by many airlines. The tug captures the nose tires and lifts the nose gear approximately three feet off the ground; allowing full control of the aircraft. The nose steering lockout pin still needs to be installed.  B737 aircraft have shorter landing gears than other Boeing aircraft making the aft area of the aircraft a blind spot; especially with the nose elevated by the Goldhofer tug. Reporter stated the B737-800 aircraft's APU; tailpipe; tail cone and an airframe bulkhead was damaged from contact with the catering truck. Elevators and horizontal stabilizer were OK. The aircraft was ferried to their Maintenance Base and was out of service for three weeks for repairs. His air carrier has implemented a new policy requiring wing walkers when pushing back B737 aircraft with Goldhofer tractors. The aircraft was originally being moved from the gate for overnight maintenance and scheduled for a morning departure. He has worked aircraft maintenance for forty-two years with three airlines.
A Line Mechanic reports he pulled a B737-800 aircraft back into the gate area after feeling something during his pushback. After walking to the back of the aircraft's tail; he noticed a food catering truck laying over on it's side.