Normal SOP Con Fig. Sequence and Calls:-
“Flap 1”-“Flap 5”-“ GearDown -F20”-“ Flap30 -LND C’list”
These calls reduce the “Speed Bug” 20Kts each call in a 4 step configuration.
However the Flap settings avail are:- 1, 5, 15, 20, 25, 30. ( 6 step/settings possible)
15 / 20 and 25/ 30 have same “Bug” settings on ASI to fly.
If on APP at “Flap 5” and you’re a bit fast for F20 you called for “Flap15” to configure(help slow down), the PNF would set the same ASI “Bug” as Flap 20 but the gear would not be down, as per the normal sequence of configuration. As PF you could forget the Bug setting is for F15 not "Gear Down-F20" so your next call is “Flaps30-LND C’list” DOH..... now your below 1500-1300' without even Gear or Flap 20.
FFRATS