OBEY (v),
 OBEYS, OBEYED, OBEYED  To do that which the procedures or instructions tell you  OBEY THE PRECAUTIONS THAT FOLLOW.  
 OBJECT (n)  Something that you can see or touch  MAKE SURE THERE ARE NO LOOSE OBJECTS IN THE AIR INTAKE.  
 observe (v)  MONITOR, SEE, OBEY  MONITOR THE RADIO ALTIMETER INDICATOR.  Observe radio altimeter indicator.
       IF YOU SEE OIL IN THE DRAIN, STOP THE TEST.  If you observe oil in the drain, stop the test.
       OBEY ALL SAFETY PRECAUTIONS.  Observe all safety precautions.
 obstruct (v)  CATCH, BLOCKAGE (n), PREVENT  MAKE SURE THE DRAG STRUTS DO NOT CATCH ON THE LANDING GEAR.  Make sure drag struts do not obstruct landing gear.
       REMOVE THE DIRT THAT  CAUSES THE BLOCKAGE OF THE TUBE.  Remove the dirt obstructing the tube.
      ADJUST THE LEVER ARMS IF THEY PREVENT MOVEMENT.  Adjust lever arms if they obstruct movement.
 obstructed (adj)  BLOCKED, CLOGGED  IF THE DRAIN HOLE IS BLOCKED, REMOVE THE UNWANTED MATERIAL.  If drain hole is obstructed, remove unwanted material.
       IF THE DRAIN HOLE IS CLOGGED, CLEAN IT.  If drain hole is obstructed, clean it.
 obstruction (n)  BLOCKAGE  EXAMINE THE DRAIN HOLES FOR BLOCKAGE.  Examine drain holes for obstruction.
 obtain (v)  GET  ADD XXXX mm TO GET THE CORRECT CLEARANCE FOR A STANDARD SPHERICAL COUPLING.  Add XXXX mm to obtain the correct clearance for a standard spherical coupling.

 
 
 OCCUR (v),
 OCCURS, OCCURRED, OCCURRED  To be found, to "come to be," to "take place"  A SUDDEN MOVEMENT OF THE CONTROLS CAN OCCUR.  
 OF (pre)  Function word that shows: "from, belonging to, having or containing"  REMOVE THE SPLIT PINS FROM THE BOLTS IN THE BOTTOM ENDS OF THE CONTROL RODS.