IAW AFI 24-605, Volume 2, Para 2.12, firm seat releases must be provided to the passenger terminal no later than 5 hours prior to mission departure and are always subject to change. Seat releases can be reduced at any time for a variety of reasons such as:
- Working/non-working toilets
- Broken seats
- Change of destination
- Hazardous cargo changes
- Non-issue of maintenance waiver
- Zero infant cots
- No Passenger Monitor available on board.
- Pallets of cargo effect the weight but so does how they are strapped down allowing safe egress to the seats.
- When an A/c is refueling it has a certain weight allowance which can limit the seats, but the fact that a wet runway/aircraft is heavier than when flying on a dry day can also cut the number offered.
If the aircraft mission issues a seat release on arrival it's only firm unless any of the above (or other) issues appear.
- Seat releases can also increases due to:
More room and weight available if a piece of cargo can't make the flight
- A leg of the mission is dropped so less fuel is required
- Maintenance issue fixed or waivered to be able to take passengers (or more passengers)
- New crew member is found to serve as a Passenger Monitor