This article is from the Vietnam FAQ, by Brian Ross, John R. Tegtmeier, Edwin E. Moise, Frank Vaughan, John Tegtmeier with numerous contributions by others.
That is not what the IO did. The IO had three roles: 1. Watch for and
call out any AAA coming up at the aircraft from below, the left side
and in front below the pilot's field of vision. 2. Fire any flares
out of the flare launcher when called for (also for jettisoning the
flare launcher in the event of major battle damage, a hung flare or an
on-board fire). 3. Drop smoke markers in the proximity of any
particularly troublesome AAA sites. The smoke allowed us to vector a
fighter in (i.e. 2,000 meters on a heading of 070 from the smoke).
Any Navy types reading this might enjoy hearing that we used US Navy
smoke markers (Mark 6?), There were the wooden ones that floated for
marking things over water.
 
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