1. Equipment
1.1. Aircraft arrive late to gate
1.1.1. gate occupied
1.1.1.1. previous flight still there
1.1.1.1.1. mechanical problems
1.1.1.1.2. arrived late
1.2. Mechanical failures
1.2.1. plane problems
1.2.2. gate ramp problems
1.2.3. baggage loading equip problems
1.3. gate checkin system down
1.3.1. got a virus
1.3.1.1. running Windows 98
1.3.1.1.1. legacy system
1.3.1.1.2. no budget for upgrades
2. Personnel
2.1. Passenger processing delays at gate
2.1.1. Passengers arrive late at gate
2.1.1.1. parking issues
2.1.1.2. curbside check-in issues
2.1.1.3. delays in checking baggage
2.1.1.3.1. self-serve baggage not working
2.1.1.3.2. checked bag fees confusing
2.1.1.4. delays in security
2.1.1.4.1. TSA understaffed
2.1.2. Not enough gate staff
2.1.2.1. Labor forecast doesn't anticipate significant late arrivals
2.2. Other late personnel
2.2.1. cabin crew late
2.2.1.1. delayed on incoming flight
2.2.2. no gate agent
2.2.2.1. handling multiple gates
2.2.2.1.1. understaffed
2.2.3. cleaning crew
3. Material
3.1. Late baggage
3.1.1. delayed leaving sorting facility
3.1.1.1. tugs not available
3.1.1.2. drivers not available
3.1.1.3. conveyor broken
3.1.1.4. problems with sorting
3.2. Unavailable items
3.3. fuel
3.4. meals
3.4.1. New node
3.5. couldn't de-ice planes
3.5.1. out of fluid
3.5.1.1. worst snow storm in a century
4. Procedures
4.1. Acceptance of late passengers
4.1.1. liberal policy
4.1.1.1. max customer satisfaction??
4.1.2. connecting flights delayed
4.1.2.1. charter group or sports team
4.1.3. late gate changes
4.1.3.1. gate not available
4.1.3.1.1. gate scheduling flawed
4.2. boarding process delayed
4.2.1. run out of overhead bin room
4.2.1.1. more people bringing carryons
4.2.1.1.1. carry on policy to liberal
4.2.1.1.2. high fees for checked baggage
4.2.2. boarding starts late
4.2.2.1. attempting to fill all standby
4.2.2.1.1. desire for full flights
4.2.2.2. process overbooked passengers
4.2.2.2.1. overbooked
5. Other Beyond Management Control
5.1. weather delays
5.2. security issues
5.3. airport mechanical problems
5.3.1. control tower navigation
5.3.2. electrical problems on runways
5.3.3. people movers not "moving"