Incident Overview
On an unspecified date, two Boeing 717-200 aircraft operated by Midwest Airlines were involved in a ground collision at Mitchell International Airport (MKE) in Milwaukee, Wisconsin. The aircraft were N904ME, operating as Flight 157, and N923ME, operating as Flight 406. The collision occurred while both were parked at adjacent gates: Flight 157 at gate D36 and Flight 406 at gate D34.
Sequence of Events
Flight 157 was initially parked at gate D36. After pushback, it came to a stop facing east, positioned behind Flight 406 and perpendicular to the gates. The captain of Flight 157 reported that the pushback was normal and that the aircraft was not positioned unusually close to the gates.
Flight 406 was preparing to push back from gate D34. The captain of Flight 406 stated that the tug driver advised them that only a limited pushback was possible because of the presence of Flight 157 behind them. The captain directed the tug driver to push back as far as possible to achieve an on-time departure. The tug driver reported that he could not see Flight 157 and that, as soon as movement began, both wing walkers signaled to stop with an "X" signal. The tug driver estimated the aircraft had moved about 5 to 6 feet. One wing walker stated that their wands were already in an "X" position before Flight 406 moved, due to the location of Flight 157.
After Flight 406's pushback, its captain set the brakes. The aircraft remained stationary for 3 to 5 minutes before the impact. The captain of Flight 157 stated that his aircraft was then marshaled forward. As he initiated a left turn, a jolt was felt, prompting him to stop and contact ramp personnel. He described the turn as not sharp. The marshaller for Flight 157 reported that the aircraft moved forward very little, if at all, before the left turn began.
Damage
N904ME (Flight 157) sustained minor damage to the outboard corner of the right side elevator trim tab end cap. N923ME (Flight 406) sustained substantial damage to the left side elevator and left side elevator trim tab.
Post-Accident Actions
Following the incident, a red Pushback Clearance Reference Line was painted on the ramp area perpendicular to gates D30 through D38. Midwest Airlines issued a Ramp Training Procedural Communication stating that both main landing gear must be on the alley side of this line at all times when an aircraft is pushed back from the gate. Additionally, Midwest Airlines reported that they are revising their Company Operations Manual to prohibit "Partial Push Backs" for the purpose of recording an on-time departure. The revision will also require that pushbacks not be initiated until the area behind and on both sides of the aircraft is clear of obstructions, ensuring a complete, uninterrupted pushback can be accomplished.