Part 121 Subpart U Dispatching and Flight Release Rules
Part 121 Dispatch Quick Reference
Can I legally dispatch to my destination?
Weather must be forecast to be at or above landing minimums at the estimated time of arrival
Do I need a destination alternate?
“1-2-3” Rule. No alternate is required if:
- One hour before to one hour after the ETA
- Ceiling is forecast to be at least 2,000 feet
- Visibility is forecast to be at least 3 statute miles
What are my alternate minimums?
Any listed alternate must be forecast to be at or above alternate minimums at the time the flight would arrive
Alternate minimums are governed by Ops Spec C055
- One-Nav Rule: Add 400-1 to the ceiling/visibility of lowest published minimums
- Two-Nav Rule: Add 200-1/2 to the higher ceiling/visibility of the two approaches being compared
- Usable CAT II: No additive required – ALT MINS 300-3/4
- Usable CAT III: No additive required – ALT MINS 200-1/2
Can I take off?
Takeoff minimums for a runway are listed on the Jeppesen xx-9A pages
Do I need a takeoff alternate?
A takeoff alternate is required if the weather at your departure airport is below landing minimums for that airport
For aircraft with two engines – not more than 1 hour at normal cruising speed in still air with one engine inoperative
Takeoff alternates must meet C055 alternate minimum requirements
Can I land at my destination?
Visibility must be reported at or above minimums for that approach prior to passing the final approach fix
If past the final approach fix, approach may be continued to DA/DH
International/Flag Dispatch
Do I need a destination alternate?
Modified “1-2-3” Rule
Any flight scheduled for more than 6 hours requires an alternate regardless of the forecast.
Less than 6 hours no alternate is required if:
- One hour before to one hour after the ETA
- Ceiling is forecast to be at least 1,500 feet above the lowest published instrument approach minimum or 2,000 feet above the airport elevation, whichever is greater
- Visibility is forecast to be at least 3 miles, or 2 miles more than the lowest applicable visibility minimums, whichever is greater
ETOPS Alternates
ETOPS alternates must meet C055 alternate weather minimum requirements from the earliest to the latest possible time of landing
Once enroute, ETOPS alternates are only required to have landing minima