Date: 201602
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Weather elements / visibility: Icing
Light: Dawn
Aircraft: Medium Transport
Operating under: Part 121
Flight phase: Parked
Aircraft component: Cowling
Reporter organization: Air Carrier
Reporter function: Vehicle Driver; Technician
Human factors: Situational Awareness; Time Pressure
Anomaly: Aircraft Equipment Problem Less Severe; Ground Event / Encounter Vehicle; Ground Event / Encounter Object; Ground Event / Encounter Loss Of Aircraft Control
Detector: Person Maintenance
When detected: Taxi
Result: Aircraft Aircraft Damaged
Contributing factors: Weather
Primary problem: Weather

Narrative: One morning I was towing the aircraft out of the hangar going tail first from the south side of the hangar when I exited the hangar and reached a down slope in the ramp with the nose wheel when the aircraft's nose got into a natural rut; low point in the asphalt; on the ramp the wheels immediately began to slide sideways from forward and aft direction to my right or the aircraft's left very quickly at first to a point that exceeded the aircrafts tow limits and left the tug in the direction of the engines. After slowing a little it picked back up in momentum and sheered the tow bar slowing the plane some and sliding the tug a little bit sideways. When the tow bar sheered the tug was near the engine and the lower engine cowling slid over the top of the tug until it hit the lower drain mast and tore it off of the engine cowling slowing the aircraft to a stop resting on the top of the tug; at which point I then exited the tug. Examining the damage that had occurred and assessing what to do next. Noting that the asphalt was excessively slick and the ramp was indeed covered in ice that had not originally been noted by me except in only a few spots that I had viewed prior to towing the aircraft. I then grabbed the chalks from the top of the tug and triple chalked the aircraft noting the damage to both the aircraft and the tug. It is my opinion that in this case I got lucky in that the only major damage to the aircraft was the drain mast and a small amount of paint damage to the cowling. When the engine and cowlings where later examined; only the shear pin was affected on the nose gear. Gear retraction; centering and taxing checks where preformed no defects outside of the before mentioned where located.There are multiple suggestions and actions in which could have been implemented to prevent this occurrence both by myself and my employer that have been discussed and thought over. One is that given the nature of the weather that had occurred the night prior I could have been more cautious in examining the ramp while I did look at it prior to towing and established areas of ice. With the icing condition that was apparent I have come to the opinion that I should have walked the ramp myself to attain a more through awareness of the severity of conditions in this case something closer to rime ice. I did have an additional hand available and though it is not his duty to assist in towing aircraft I could have asked him for assistance in wing walking the aircraft and though I feel that the outcome would have been the same regardless of personnel available except in another individual noting the extreme conditions or as unlikely as I see it possibly chalking the wheel even though the whole aircraft slid despite the nose wheels being turned a different direction entirely and the whole aircraft was on a sheet of ice though the mains did not slide as much they did slide toward the rut; it is because of this I feel that a second hand though advisably a wiser option may very well have only been hurt in the process. Or possibly have helped in avoiding of the incident. As a whole I will not exclude that possibility despite my belief in its probable failure as well given the circumstances. It was the owner of the company who stated it best when notified of the incident. He asked simply why I had towed the aircraft on an icy ramp to which my only response was and is that it was due to fly very shortly; to which his preceding comment was so why wasn't the ramp de-iced. All of these are factors that I believe to be the causing agents in this particular incident; to which I can only act with much more caution in my future actions as well as getting assistance regardless of time restraints and watch for adverse weather conditions more effectively. The addition of anti-icing for the ramp has also been noted and is in preparation by my superiors. Lighting may have increased my awareness of the true circumstances as the lighting in the facility only extends a little way onto the ramp area although well enough to see the ramp but we are talking about operations at five to six in the morning and lighting will always be a problem at this time .




Synopsis: A mechanic lost control of an aircraft while pushing aircraft out of the hangar onto an icy ramp area. The tug slid under and engine cowl and broke off drain mast.