HATCH INSPECTION

HATCHES, LIKE DOORS, REQUIRE REGULAR INSPECTION.  SOME COMPONENTS OF HATCHES, LIKE THEIR KNIFE EDGES AND GASKETS, ARE ESSENTIALLY THE SAME AS THOSE ON DOORS, WHILE OTHERS, SUCH AS THE MECHANISMS TO SECURELY BRACE OPEN HATCH COVERS, ARE UNIQUE.  THE DOGS ON RAISED HATCHES ARE BOLT-ACTUATED, NOT HANDLE-ACTUATED, AND THEY HAVE THEIR OWN INSPECTION PROCEDURES.

1. EXAMINE THE KNIFE EDGE AND GASKET FOR DISTORTION AND WEAR.
   
   
2. PERFORM A BASIC CHALK TEST TO DETERMINE IF THE CLOSURE IS WATERTIGHT.
   
   
3. INSPECT THE DOG BOLT THREADS AND NUT FOR WEAR BY CHECKING FOR EXCESSIVE WOBBLE BETWEEN THE NUT AND THE BOLT.  IF THERE IS APPARENT WEAR, CONSIDER REPLACING THE DOG BOLT ASSEMBLY.
   
   
4. FLATS ON DOG BOLT NUTS CAN WEAR DOWN AND OTHER TYPES OF DAMAGE CAN RAISE OR DISTORT THE FLATS NEAR THEIR EDGES.  CHECK THE FLATS ON THE DOG BOLT NUT BY CAREFUL PHYSICAL EXAMINATION AND BY MAKING SURE THE DOG BOLT WRENCH GRIPS IT PROPERLY.
   
   
5. MAKE SURE THE COLLAR THAT SECURES THE NUT WHEN A HATCH IS OPENED IS NOT MISSING FROM THE TOP OF THE DOG BOLT.
   
   
6. AFTER INSPECTING DOG BOLTS, LUBRICATE THE BOLT THREADS WITH A LIGHT COATING OF SILICONE COMPOUND BEFORE REPLACING THEM.
   
   
7. THE HATCH COVER BRACE, WHICH HOLDS THE COVER UPRIGHT WHEN THE HATCH IS OPEN, INCLUDES A BRACE PIPE FASTENED TO THE HATCH AT ONE END AND A TOGGLE BOLT.  THE TOGGLE BOLT MUST BE FASTENED TO THE FREE PIPE WITH STAINLESS STEEL AIRCRAFT CABLE.  WHEN NOT IN USE, THE FREE END OF THE BRACE IS HELD TO THE HATCH COVER BY A SPRING CLIP.  WHEN IN USE, THE FREE END OF THE BRACE IS ATTACHED TO THE HATCH COAMING BY THE TOGGLE BOLT.  HATCHES MUST BE INSPECTED TO SEE THAT ALL THESE PARTS ARE PRESENT AND INTACT.
   
   
8. THE BRACE SHOULD BE TESTED BY OPENING THE HATCH AND MAKING SURE THE BRACE WILL HOLD THE HATCH COVER OPEN AND THAT THE TOGGLE BOLT IS THE RIGHT SIZE TO SECURELY HOLD THE FREE END OF THE BRACE TO THE COAMING.
   
   
9. BECAUSE IT IS DIFFICULT TO SEE WEAR ON HATCH HINGE PINS, TAKE CARE TO CLOSELY INSPECT THE HINGES AND ALL THEIR COMPONENTS.  WHEN INSPECTING HINGES, CHECK TO SEE THAT ALL COTTER PINS AND WASHERS ARE PRESENT.
   
   
10. MAKE SURE THE WRENCH IS IN PLACE.  INDIVIDUALLY DOGGED HATCHES EACH HAVE AN ENGINEER'S WRENCH HELD TO THE HATCH BY A CLIP, BOLT AND WING NUT OR OTHER SECURING MECHANISM.  FLUSH HATCHES SIMILARLY ALL HAVE A T-WRENCH ATTACHED TO THEIR INSIDE SURFACE.