When the prescribed minimum altitude for IFR operations is at or above 18,000 feet MSL and the atmospheric pressure is less than 29.92”, add the appropriate adjustment factor from TBL 4-5-3 to the flight level equivalent of the minimum altitude in feet to determine the adjusted minimum flight level.
| Altimeter Setting | Adjustment Factor |
|---|---|
| 29.92” or higher | None |
| 29.91” to 29.42” | 500 feet |
| 29.41” to 28.92” | 1000 feet |
| 28.91” to 28.42” | 1500 feet |
| 28.41” to 27.92” | 2000 feet |