Doug (an instrument student) was flying the ILS at Mansfield, OH. A mile from the airport the tower told us to break off the approach, turn left and enter the downwind leg of a crossing runway. There were two C-130s (large military cargo planes) that were going to "drop bundles" on the airport. No one including the tower knew what the bundles were. (They sometimes drop jeeps out of C-130s.) As we started the turn, I could see the headlights of the C-130's coming toward us. The tower ultimately cleared us to land.
Meanwhile the tower was talking to ground, "Tower to ground, do you have the bundles?... Tower to ground how do you copy?... Are the bundles clear of runway 5 (our runway)?... Tower to ground"
By now we were less than 100 feet and a few seconds from landing. Then we noticed our landing light was not working. I called the tower, "Mansfield tower, 6066H, do you want us to go around?"
The tower quickly replied, "Affirmative 66H, go around."
About 300 feet off the ground during the go around, our heads banged off the ceiling and the plane rolled at least 45 degrees. We had hit the wake turbulence of the C-130's. Another plane a minute behind us also reported the wake. At 300 feet the wake was a nuisance. Near the ground while landing it could have flipped us over or at least bent some metal on the landing.
We flew the pattern one more time and were cleared to land. No landing light makes the landing a little tougher but not impossible or dangerous. At the end of the rollout the tower called, "66H are you OK." Doug replied, "Sure, we're OK." The tower responded, "Well, we are not sure we found all the bundles. Did you see any on the runway?" I fessed up, "Sorry, our landing light was inoperative." Then the tower told the airplane behind us to go around again. They finally let him land on the next approach. We never found out what the bundles were or how many.