Takeoff Alternate Requirements

What Is a Takeoff Alternate?

A takeoff alternate is an alternate aerodrome specified in the flight plan, intended for use if an emergency or technical issue prevents a safe return to the departure airport shortly after takeoff. This is especially critical when weather or operational limitations at the departure aerodrome make an immediate return unsafe or impossible.

When Is a Takeoff Alternate Required?

A takeoff alternate must be selected if the weather at the departure aerodrome is below the published landing minima at the time of takeoff, or if operational circumstances (such as runway closures or performance limitations) prevent a safe return. The requirement applies primarily to IFR operations and is a key part of flight planning for commercial air transport.

Takeoff Alternate Distance Limits

• Two-engined aircraft (non-ETOPS): Must be within 1 hour's flight time at one-engine-inoperative (OEI) cruise speed under ISA conditions, using actual takeoff mass.
• ETOPS-approved aircraft: May use the ETOPS diversion time, up to a maximum of 2 hours at OEI cruise speed, subject to MEL restrictions.
• Three or four-engined aircraft: Must be within 2 hours' flight time at OEI cruise speed under ISA conditions, using actual takeoff mass.
• Single-engined turbine (SET-IMC/Night): 30 minutes at normal cruise speed.

Takeoff Alternate Weather Minima

The takeoff alternate must have weather forecasts and reports indicating that, from one hour before to one hour after the estimated time of arrival (ETA), the conditions will be at or above the landing minima for the expected approach. For non-precision approaches, ceiling requirements must also be met.

Factors in Selecting a Takeoff Alternate

• Runway length and surface suitable for the aircraft type and weight
• Availability of required approach aids and lighting
• Air traffic services and communications
• Meteorological services
• Rescue and firefighting services
• Accessibility considering one-engine-inoperative performance

Accessibility for ETOPS

For ETOPS flights, the takeoff alternate must be accessible within the approved ETOPS diversion time, and all relevant operational and MEL limitations must be considered.