Incident Overview
On December 26, 2012, at 0215 Central Standard Time, a Boeing MD-11F, registration N612FE, operated by Federal Express Airlines as flight 1480 from Memphis International Airport (KMEM) to Portland International Airport (KPDX), struck a deicing vehicle while being marshaled onto the "E" deicing pad at KMEM. The aircraft was substantially damaged, the deicing vehicle was damaged, and there were no injuries to the two flight crew members and one jumpseat passenger. The ground employee in the deice bucket experienced a minor injury. Weather conditions at the time included dark lighting, 2 miles visibility in blowing snow, and clouds at 900 feet.
Sequence of Events
The flight crew reported that they taxied to the deice area and called the deice pad coordinator. They taxied the airplane onto the pad in response to marshaller lighted wand signals. The first officer observed that two vehicles on the right side of the airplane were outside the painted taxiway edge lines. The operation was not using wing walkers. The first officer noted that the wingtip area is outside the field of view from the flight deck windows. The marshaller began to signal the crew to stop, and simultaneously the deice coordinator radioed them to stop; the pilot reported feeling a shudder. The right wing of the airplane contacted the deice vehicle approximately 4 feet from the right winglet at the number 8 slat. The deice bucket passed under the wing surface, puncturing a fuel tank and causing a fuel spill of approximately 75 gallons. The coordinator advised the crew to shut down the engines and informed them of a fuel leak. The crew was unaware of the strike until informed by maintenance personnel. The airplane was towed back to parking, and the crew exited via the main entry door.
Damage Assessment
The right forward wing spar lower cap forward flange had a horizontal crack about 10 inches long. Additional damage included the right outboard aileron, right wing slats and associated hardware, right wing leading edge behind the slat, right wing fuel tip tank vent manifold, lower skin plank, and three fuel tank panels. The lower wing skin aft of the damaged spar cap was punctured, and one lower wing stringer was deformed. The damage to the spar cap, lower wing skin, and lower wing affected the structural strength of the wing, resulting in substantial damage to the airplane per 49 CFR 830. The deice vehicle boom arm was also damaged.
Contributing Factors
Deice pad E is located on Taxiway C, north of Taxiway V and adjacent to a parking apron. A FedEx document titled "Carwash E Parking Plan" indicates that on deice pad E, MD-11 airplanes must be positioned east of the Taxiway C centerline to provide proper clearance. The flight crew followed ground personnel marshaling instructions onto the deice pad. The marshaller and maintenance technician working on pad E had never worked at that location before and were unaware of the requirement to taxi MD-11 airplanes off centerline. The diagrams provided to the marshaller and coordinator were unclear and not sufficient to be standalone documents.