sandrich

Not sure if this is what you're referring too, but when I was at Republic flying the 175, our company was too cheap to buy the ozone scrubbers for the cabin. We had two sets of charts we would have to look at. Its been awhile, but if I recall correctly, along the top was your time of the year by month, and going down the side was your latitude in degrees. You would just enter the chart at the appropriate latitude/month. I believe the value on the chart was the highest FL you can be at for no more than 2 hours. Then there was another chart which would tell us the highest FL we could be at for the duration of the flight.

Example- April was usually the worst time of the year for us. I remember doing a flight from Montreal-Houston. We would start at FL320, stay there for 2 hours, then drop down to FL260 for the remainder of the flight for Ozone.

Since we carried the charts in our manuals on board, all we had annotated on the release on the top was something along the lines of "This flight has been planned in accordance with ozone risk management/exposure procedures. Reference ozone chart..."