Northwest Airlines (NWACQ.PK) today announced several executive appointments and is increasing the responsibilities of three other officers, as it reorganizes its operations group. Crystal Knotek was named senior vice president-ground operations, replacing Robert Isom, who left left the company. Knotek is responsible for customer service and ground operations at Northwest, reporting to Andrew Roberts, executive vice president-operations. She had been serving as vice president-reservations and customer care. Chris Collette was appointed vice president-finance and staffing for the airline's ground operations, reporting to Knotek. He replaces Glenn Woythaler, vice president-customer service planning, who is leaving the airline. Collette formerly was managing director-technical operations finance and planning. Tim Rainey was named to a broader role as senior vice president- flight and in-flight operations, consolidating the two organizations into a single function. Rainey formerly was senior vice president-flight operations. Suzanne Boda, vice president-in-flight services, will now report to Rainey. In addition, Ken Hylander, vice president-safety and engineering and chief safety officer, has now assumed responsibility for all safety and quality activity within the operations group.