What is alternate fuel in ATPL fuel planning?

Alternate fuel is the amount needed to fly from the missed approach at the destination to the alternate aerodrome, including climb, cruise, descent, approach, and landing.

How is contingency fuel calculated for alternate fuel planning?

Contingency fuel is typically 5% of trip fuel, but may be reduced under certain conditions or calculated as 5 minutes at holding speed at 1500 ft above destination.

What is the minimum fuel required if no destination alternate is available?

You must carry enough fuel to hold for at least 15 minutes at 1500 ft above the destination aerodrome at expected landing mass.

When must two destination alternates be selected?

Two alternates are required when weather or operational conditions make both the destination and first alternate marginal or unavailable.

What is final reserve fuel in the context of alternate fuel calculation?

Final reserve fuel is the minimum fuel required for 30 minutes of holding at 1500 ft above the alternate aerodrome for turbine aircraft.

Fuel Planning for Alternates

Hard4 min readOperational Procedures

Moderately Examined

Why this matters

Accurate alternate fuel planning is essential for flight safety, ensuring that unexpected weather, traffic, or technical issues do not compromise the ability to reach a safe landing site. It underpins sound decision-making and compliance with legal and operational standards.

Fuel planning for alternates ensures that, if a diversion from the planned destination is necessary, the aircraft has enough fuel to reach a suitable alternate aerodrome safely. This calculation includes not just the fuel to reach the alternate, but also reserves for contingencies and holding, based on regulatory requirements and operational factors.

Quick Check

Which fuel component specifically covers the amount required to fly from the missed approach at destination to an alternate aerodrome, including approach and landing at the alternate?

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Explanation

Components of Alternate Fuel Calculation

When planning fuel for an alternate airport, several distinct fuel quantities must be considered:

Trip Fuel: Covers the fuel required from departure to the planned destination.
Contingency Fuel: Accounts for unforeseen factors, typically the greater of 5% of trip fuel or 5 minutes holding at 1500 ft above destination.
Alternate Fuel: The fuel needed to execute a missed approach at the destination, climb, cruise, descend, and land at the alternate aerodrome. If two alternates are required, the greater fuel requirement is used.
Final Reserve Fuel: For turbine aircraft, this is fuel for 30 minutes at holding speed at 1500 ft above the alternate's elevation; for reciprocating engines, 45 minutes.
Additional/Extra Fuel: At the commander’s discretion, for expected delays or adverse conditions.

Special Cases

No Alternate Required: If no alternate is planned (e.g., isolated aerodrome), holding fuel for 2 hours at normal cruise consumption (turbine) or as specified for the aircraft type is required.
Predetermined Point (PDP) Procedure: When the distance between destination and alternate is significant, fuel must be sufficient for either route (to destination or alternate via PDP), with the greater requirement used.
Reduced Contingency: With an en-route alternate, contingency fuel may be reduced to 3% of trip fuel or calculated for 20 minutes at cruise.

Fuel Calculation Example

For a typical flight requiring an alternate:

Calculate taxi, trip, and contingency fuel.
Add fuel for a missed approach, climb, cruise, descent, and approach to the alternate.
Add final reserve fuel for holding at the alternate.
Consider any additional fuel as needed.

Regulatory Compliance

All calculations must meet EASA fuel requirements, ensuring that, even in the event of a diversion, the aircraft can safely land with required reserves intact.

The essentials

Key Points

Alternate fuel includes missed approach, climb, cruise, descent, and approach to the alternate.

Final reserve fuel is 30 minutes at 1500 ft holding speed for turbine aircraft, 45 minutes for piston.

Contingency fuel is typically 5% of trip fuel or 5 minutes holding at 1500 ft above destination.

If no alternate is required (e.g., isolated aerodrome), 2 hours at normal cruise consumption is needed (turbine).

When two alternates are required, use the greater alternate fuel requirement.

Additional fuel can be carried at the commander's discretion for expected delays.

All calculations must comply with EASA minimum fuel requirements.

Watch out

Exam Traps & Typical Mistakes

Confusing final reserve fuel with alternate fuel—final reserve is for holding at the alternate, not the destination.

Forgetting to include the missed approach and climb to cruise when calculating alternate fuel.

Applying the 2-hour holding requirement for isolated aerodromes to standard flights with alternates.

Assuming contingency fuel can always be reduced—this is only allowed under certain conditions.

Mixing up requirements for turbine and reciprocating engine aircraft regarding holding times.

Test yourself

Example Exam Questions

Question 2Easy

When planning fuel for a flight with no alternate aerodrome available, what is the minimum holding fuel requirement at 1500 ft above destination elevation?

Question 3Hard

For a turbine-engine aircraft using the predetermined point (PDP) procedure, what is the minimum additional fuel required when routing to the alternate via the PDP?

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