BOMBSIGHT PRE-FLIGHT CHECK

INSTALLATION

1. Match sighthead and stabilizer
2. Insert clevis pin and dovetail locking pin
3. Check for security of cannon plugs
4. Turn ‘STAB” on. CROSSTRAIL MECHANISM
5. Check for pre-set trail Rotate dovetail shaft Crosshairs do not move
6. Check for dovetail misalignment
Zero drift, small sighting angle, small drop angle
Move trail arm, crosshairs do not move
7. Check tilt of optics
Move sighthead 30° right, move trail arm, crosshairs move right
Move sighthead 30° left, move trail arm, crosshairs move left
Set trail 150°, move sighthead left and right, telescope should move

RATE END

8. Turn “BS” on
9. Check Rate, Displacement, Search knobs
When sight angle is moved to zero, it should spring back at least 20° Check Extended Forward Vision knob
10. Check Rate Motor and optical drive
11. Check Disc Speed Drum and Speed Gearshift
12. Check for pre-set trail in the Rate End
Drop angle -.05, trail set at 50 mil, maximum disc speed
Engage mirror drive clutch, sighting angle index should not move
13. Check for roller slippage
Set disc speed of 265
At any drop angle, when the sight angle matches it, it should take 20 seconds to reach zero
Use bombing tables and set disc speed and note time to fall
Place drop angle at 0.75 and sight angle at 42°
From the drop angle, the sight angle should reach zero at time to fall
14. Check mirror drive cable length

STABILIZER AND COURSE KNOBS

15. Turn “SERVO” on
16. Check Course knobs and PDI Engage Bombsight Clutch
Turn sighthead with Turn knob
Sighthead moves, and PDI Turn Drift knob
Sighthead does not move, but PDI does
17. Check torque unit and Bombsight Clutch
Engage Bombsight Clutch
Try turning sighthead manually
18. Check Autopilot Clutch Disengage Bombsight Clutch Engage Autopilot Clutch
Turn the Drift knob
PDI does not move
19. Check PDI with pilot
Engage Bombsight Clutch
Use drift knob

SIGHT VERTICAL AND LIGHTING

20. Check vertical gyro by uncaging
21. Check leveling knobs
22. Check bubble light
23. Check crosshair rheostat

Here is a video of a Norden Bombsight Preflight Checklist being conducted: