Date: 201505
Flight conditions: Mixed
Weather elements / visibility: Thunderstorm
Aircraft: Widebody; Low Wing; 4 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Taxi
Reporter organization: Air Carrier
Reporter function: Lead Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Distraction; Communication Breakdown; Workload
Anomaly: Aircraft Equipment Problem Less Severe; Ground Event / Encounter Other / Unknown
Detector: Person Maintenance
When detected: Other During Tow and Taxiing
Result: General None Reported / Taken
Contributing factors: Company Policy; Aircraft; Human Factors; Weather
Primary problem: Weather

Narrative: Assigned to reposition [International Air Carrier X] A340; under contract maintenance with our [Domestic Air Carrier X]; using a large Goldhofer towbarless tractor. Thunderstorms were active in the area; and remained active for the duration of this operation. The purpose of this report is to bring attention to the fact that despite repeated observations and assertions by employees that to move aircraft such as this in adverse conditions with towbarless tractors presents obvious compromises in safety for a variety of reasons explained in text below. Pressure continues to exist and emanate from local Line Maintenance Management at ZZZ for Leads to assign and utilize the Goldhofers as much as possible for a variety of reasons; with little or no regard for the concerns of the [tractor] operators ultimately assigned to perform the assignment. This is not a recent development at [our] ZZZ Maintenance and has been and continues to be a concern since the introduction of the Goldhofer fleet to our Line Maintenance several years ago.In this instance; I was assigned to use a Large Goldhofer unit to reposition an Airbus A340 aircraft; which is presently [one of] the larger wing spanned aircraft in present service at [this] airport at 208'11' inches. The B747-800 wingspan is 224' feet and a 747-400 such as in our Air Carrier X fleet is 211' feet. When towing any aircraft of this category; the wingtip clearance is critical when towing in certain locations of both the International and Domestic terminals as well as commonly used taxiways such as taxiway Alpha; commonly assigned by local ATC during this operation.Use of the Goldhofer in clear daylight conditions is not the issue. When using the same equipment:1) at night or twilight; 2) in rain or other precipitation conditions; the critical margins of safety become severely compromised. In dusk; twilight; or night operations; the cab of the Goldhofer becomes a veritable lightshow with reflections from buildings; airport; taxiway; and other aircraft lighting on areas within the field of vision for the driver. I have found it necessary to actually open windows or doors of the tractor to improve the required field of vision to simply ensure clearances; not to mention looking for other moving aircraft and/or ground equipment present on the Airport Operations Area (AOA). When driving on wet surfaces; at ground level from the tractor; ground pavement markings; taxiway; ramp markings and other mandatory markings and/or signage become invisible.Wingtip clearances with large aircraft such as this is absolutely critical when towing on taxiway Alpha as aircraft are often parked up to the edge of the movement-non-movement area. In daylight; from the cockpit; this line is plainly visible. At night; marginally visible. At night; with wet surfaces; from the cab of the Goldhofer; impossible.These concerns and others like it are often brought to the attention of our Air Carrier X Line Maintenance. Management at [this] airport; with seemingly little or no effect. The pressure is on to utilize the equipment; for a variety of reasons; some unknown to me.Recently at our Line Maintenance at ZZZ; new policies and procedures have been instituted regarding aircraft movement in the hangar and ramp area which in the eyes of this Reporter; are restrictive and border on overkill. Not questioning the value or necessity of guide man; safety observers; etc. in this forum; but suffice to say that once I or any of my co-workers leave the highly restrictive and regulated hangar area into the AOA controlled taxiways; all bets are off and we are basically on our own.Simply put; in adverse conditions such as described above; park the Goldhofers and assign a two man Taxi Crew to facilitate the move in the absolute safest possible manner to accomplish the mission assigned: safely reposition the aircraft and send the aircraft and its passengers on its way. Any attempts to save money by continued useof this equipment in these situations is narrow-minded and only places the employees assigned to do the job in a very bad; compromised position relative to safety. We preach and continually hear that safety is our primary concern. Continuing to placed employees and equipment in this above described situation and others similar to it only undermine in a very real way; the highest level of safety that we are all interested in and should continually strive for. Ground / Ramp. Aircraft Handling. Maintenance. Contracted Maintenance.




Synopsis: A Lead Aircraft Maintenance Technician (AMT) reports that repeated observations and assertions by employees to their Line Maintenance Management that moving large aircraft such as B747-400s; A340 and B747-800 in adverse weather conditions with towbarless tow tractors presents obvious compromises in safety for a variety of reasons; compared to taxiing of aircraft.