B787 Dreamliner Undifferentiated or Other Model
Ground Event / Encounter Other / Unknown; Ground Incursion Taxiway
General None Reported / Taken
Equipment / Tooling
My partner and I were pushing a 787 with a super tug. The push went smoothly with no warning signals coming from the super tug. As soon as I was done with my push I spin the set around and my observer got into the tractor so we can move forward to go to the top and over to ground as directed by Ramp Tower. As soon as I put the super tug into drive the 'Over steer' alarm went off. The 'Over steer' is a flashing Red Screen and a Warning siren to let the crew know that the Super Tug has an over steer and that has to do with the hydraulic system and the airplane in the cradle of the super tug. When the alarm siren went off it was so loud in the cabin where the driver and observer sit that we could not hear the ATC Ground Tower. When my observer went to make his first call to the ATC tower to get directions to our holding pad in the west hangar; the ATC said that he could not hear our transmission over the alarm siren. There is no way for us to lower or turn off that siren until we lower the airplane and open the cradle and move the super tug away from the airplane. Also the Mechanics have a key to where they have to reset the computer and warning alarms. My observer had to step out just to make the call and when he gave us direction we both did not copy it was to what we both thought we heard and what my observer repeated back to the ATC. The call was to turn right onto X Taxiway and hold short of Y1. We both thought over the Over Steer warning Siren that the ATC said to turn right onto Y and hold short of Y1. ATC got back on the radio and told us that we missed our instructions and we went the wrong way. The whole tow was very difficult to hear ATC instructions and we had to keep on asking him to repeat the instructions. This was very dangerous and unsafe to have that siren that loud and could have caused an accident; near miss; and/or a surface incident. I had to take off my jacket when holding short of Y2 to try and muffle the warning siren just so we would miss any more calls and we can hear the ATC as well as for them to hear us read back instructions. The jacket didn't do much muffling of the alarm. At the end of my tow and securing the A/C we took the super tug down to the garage and I let the lead mechanic know the issue. The lead mechanic said he will look into the volume of the over steer warning.
Ramp agent reported that an extremely loud warning signal in the tug being used for a push made it diffucult to hear Ground Control's instructions.