Hi. My brother was just making a route when I noticed that when My brother used Fokker f28-4000 which had economy 50 and business 10 on his Phuket-Beijing route, it only said 7 people in business class as the capacity whatever the day. Help!
Did you check the range? That's nearly 4000km - much too long for that type. It still does the route, but with a maximum of 711kg of payload - that's only 7 passengers.
This is like in reality. Make sure that your aircraft is able to lift the payload and fuel from airport X with runway length Y to destination Z. The cute Fokker F28 was designed as a short haul-jetliner and does not provide the performance to do such long routes with a normal payload. You should always calculate the balance between payload/fuel and range. There is a performance-diagram and you can see the "point" where the payload deteriorates (fewer pax).
One example: one of my A320-200 medium is scheduled to fly Jakarta - Adelaide. The diagram shows "88,4%". This means that this A320 can do this route but won´t be able to to this mission with full payload (180 pax + baggage + cargo). The payload is reduced and the fuel needed for do this route has priority. Due to the fact that I am using the A320 with 144 seats (36 seats below maximum), all seats can be booked because of the "gap" between the payload required and my payload equivalent to 144 pax. The reduction from 100% to 88,4% does not affect my flight. In other words, a 180-seat A320 would suffer payload-restrictions and I won´t be able to occupy all 180 seats.
In reality Bangkok Air once operated their short haul Boeing 717 on longer routes to PR China from Thailand and some of these routes suffered payload-restrictions (due to a mix of range, altitude, temperature etc.) to enable the 717 to do these missions and two to three rows were left empty (equivalent to 10 to 15 seats) and thus the seat capacity was reduced from the standard 125-layout to 115 or even 110. This is not a rare occasion in civil aviation but affects the 717 in this example due to the high seating-capacity close to the maximum permitted and the length of the route. A 110-seat Boeing 717 would probably not have suffered these restrictions on this route but a 125-seat plane did.
Some of my airplanes are rostered on routes which won´t be able with maximum seating-capacity but with my arrangements there are doing OK.
The maximum range with max payload (85 pax) for a Fokker F28-4000 is for example Phuket - Jakarta. Please consider that the Fokker F28 is very difficult to operate due to lack of efficiency. I would instantly operate these wonderful planes but there are not longer viable. However they can be operated profitably (I´ve tried this several times).
Use the performance calculator from the aircraft model specification page, it will take runway length and flight distance into account to tell you how your aircraft will perform. For payload calculations, each passenger regardless of class is 95kg, and each unit of cargo is 100kg.
For the F28-4000, max payload is 10 450kg, while due to flight distance, the aircraft can only carry a calculated payload of 711kg. As this aircraft doesn’t carry cargo, the calculation is 711/95=7.48 passengers. As you cannot transport part of a passenger, your maximum capacity for this flight is 7 passengers.
When restricting payload, the game first reduces cargo capacity, then economy class passengers, then business, and finally first class passengers, if equipped. So your 7 passengers are all business class.