IWC Schaffhausen BIG PILOT'S Le Petit Prince Mode D'emploi page 26

This watch has a screw­in crown. Screwing the crown in to its
normal position (X) prevents the inadvertent adjustment of the
time or annual calendar and also acts as a double seal to prevent
water from seeping into the case. To release the crown, unscrew
it by turning it to the left, where it automatically assumes position
0, the winding position. By depressing the crown into position X
and turning it to the right at the same time, it is screwed down
firmly again and secured.
B I G P I L O T ' S WAT C H A N N U A L C A L E N D A R
F U N C T I O N S O F T H E C R O W N
Normal position (screwed in)
X —
Winding position
0 —
Setting the calendar
1 —
2 —
N O R M A L P O S I T I O N
— 2 6 —
X
Time setting
0 1 2