Event Overview
On May 12, 2014, at about 1737 eastern daylight time (EDT), Delta Air Lines flight 1612, a Boeing MD-90 (registration N933DN), experienced a partially collapsed nose gear during pushback from the gate at Boston Logan International Airport (KBOS), Boston, Massachusetts. The flight was a 14 Code of Federal Regulations Part 121 regularly scheduled passenger flight between KBOS and Minneapolis-Saint Paul International Airport (KMSP), Minneapolis, Minnesota. The passengers and crew exited the aircraft via the jet bridge, and there were no injuries.
Flight Crew Actions
According to the flight crew, during pushback they received a new route clearance due to weather along the route. The captain and first officer discussed how they would handle the associated tasks and agreed they would load the new route and then contact dispatch after the engine start had been accomplished. The crew stated the interphone conversation quality was degraded due to low volume, and there was considerable radio traffic on both clearance delivery and ramp frequencies. As the flight crew finished coordinating tasks, the captain heard on the interphone what he believed was "set brakes" and, because he did not discern any aircraft motion, began to apply the brakes. The airplane immediately shook and several warnings went off in the cockpit.
Tug Operator Account
According to the tug operator, while at the gate he received "brakes released" and "clear to push" from the flight crew, and he proceeded to push the airplane off the gate and to the area where it was clear to start engines. As the airplane approached the engine start spot, the tug operator stated "cleared to start," and the airplane immediately stopped. The tug operator saw the airplane nose immediately drop and the nose gear partially collapse.
Damage
Further inspection revealed the airplane sustained substantial damage to the nose landing gear assembly.