Hello, Big Black,
The phenomenon is this:
The toilets on the big planes use a blue colored deodorant infused water to flush toilets while in flight. Occasionally, some of these holding tanks will develop a leak at the drain seal and water will seep out . At altitude, the temps are way below sub zero, hence ice forms. While the water keeps seeping out, it forms a big ice ball which breaks away and falls on people's stuff. On some aircraft, these large ice balls can form up in the wheel well area and when the gear is extended the ball falls out.
I hope this clarifies what is a "Boeing Bomb."
If wishes were horses, a Tail Dragger I would fly...