ok, let's create a scenario
Plane A - A320
Pilot pairs: A1 - A10 (10 sets)
let's say Plane A flies to HKG twice daily, 6am flight and 6pm flight from SIN
To and fro takes around 7.5hrs at least
MONDAY - A1(am), A2(pm)
TUESDAY - A3(am), A4(pm)
WEDNESDAY - A2(am), A1(pm)
THURSDAY - A4(am), A3(pm)
FRIDAY - A1(am), A2(pm)
SATURDAY - A3(am), A4(pm)
SUNDAY - A2(am), A1(pm)
let's say pilots work every alternate days, this is the above roster roughly
when the plane comes back from HKG at 1.30pm, it will not idle at the airport, it will fly a short trip to maybe Penang or KL and back (twice) before 6pm for its second trip to HKG.. That's where pilot pairs A5-A8 comes in.. A9 and A10 will be on standby or on rotation since pilots usually dun work as frequently as alternate days
how about the time between 1.30am and 6am?? ground the plane at airport?
does 10sets of pilot pairs look a lot to you now?