Short answer: MINIMUM FUEL warns ATC that, after committing to a landing aerodrome, a further change could put landing fuel below planned final reserve. It gives no priority. Under the EASA CAT rule, declare MAYDAY MAYDAY MAYDAY FUEL when the predicted usable fuel at the nearest safe landing aerodrome is below that reserve.
Fuel emergency vs minimum fuel questions require a landing prediction. The quantity in the tanks is only the starting point: name the landing option, the route and the usable fuel expected on arrival.
Scope: The examples use EASA commercial air transport (CAT) aeroplane rules in Part-CAT. The short US comparison uses the FAA AIM. The figures are teaching inputs; aircraft manuals and the operator's procedures govern actual operations.
Fuel emergency vs minimum fuel under EASA rules
CAT.OP.MPA.185(c) and (d) set two mandatory declaration triggers. Once committed to a particular aerodrome, the commander must declare MINIMUM FUEL if a change to the clearance may reduce landing fuel below the planned final reserve. GM1 CAT.OP.MPA.185(e) also addresses other factors that delay landing, such as deteriorating weather.
The fuel emergency trigger is a prediction below planned final reserve at the nearest aerodrome where a safe landing is possible. The declaration is MAYDAY MAYDAY MAYDAY FUEL. Do not wait for the fuel currently on board to reach the reserve quantity.
GM1 CAT.OP.MPA.185(k) explains the practical aim: protect final reserve and declare the emergency when that protection is no longer possible. An earlier MAYDAY may be necessary if the overall situation already demands emergency assistance; a forecast exactly equal to reserve is no reason to stop assessing the risk.
Practise this exact question with a free model answer.
Before you commit
Obtain delay information from a reliable source if unforeseen circumstances could bring predicted destination landing fuel below final reserve plus any required alternate or isolated-aerodrome fuel. Under the basic fuel scheme, with a required destination alternate, compare destination, alternate and other adequate aerodromes while there is still a choice. If no destination alternate is required and predicted destination landing fuel falls below final reserve, take action to reach an aerodrome where you can land safely with at least final reserve.
That sequence follows CAT.OP.MPA.185(b) and AMC1 CAT.OP.MPA.185(a), paragraph (b)(2). Agree when to reassess the landing plan with the other pilot before the approach becomes busy. Brief the applicable declaration triggers and recalculate when a delay, runway change or revised route affects the landing prediction.
A related interview discussion is Q36 in the pilot interview questions and answers guide. In an interview, explain how you obtain delay information and reassess early. If the emergency trigger is already met, make the distress call immediately while the crew coordinates the landing.
What is final reserve fuel?
For a turbine-engined CAT aeroplane, CAT.OP.MPA.181(c)(5) sets a minimum of 30 minutes at holding speed, 1,500 ft above aerodrome elevation in standard conditions. The calculation uses estimated arrival mass at the destination alternate, or at destination when an alternate is not required. GM1 CAT.OP.MPA.181(i) permits conservative, rounded-up reference values for each type and variant.
Final reserve is a planning and protection quantity. It is not a fixed endurance remaining from the aircraft's present altitude, configuration and fuel flow. Nor does the 30-minute value mean that the emergency call should wait until the tanks contain only 30 minutes of fuel.
See CAT.OP.MPA.181(c)(5) and its guidance for the calculation basis.
A worked fuel scenario
Use these fictional arrival predictions for a ground exercise. Both rows assume a two-pilot crew in contact with Approach. In flight, use the actual usable fuel, route and performance predictions for the aeroplane, and brief the landing plan and division of duties under your SOP.
| Situation | Given information | Explanation to practise |
|---|---|---|
| Committed landing option | Final reserve 1,200 kg; landing forecast 1,400 kg; possible clearance change costs 250 kg | The change would leave 1,150 kg. Declare MINIMUM FUEL because the crew is committed and the change could put landing fuel below reserve. |
| Deteriorating forecast | The nearest safe landing option now predicts 1,100 kg, with the same 1,200 kg reserve | Declare MAYDAY MAYDAY MAYDAY FUEL. Also investigate why the prediction fell: compare fuel on board plus fuel used with the departure quantity, allowing the type's tolerances, and follow the type's fuel-leak procedure when indicated. |
The second row's fuel-monitoring check is illustrated by Airbus, Fuel Leak Management in Flight. It is a type-specific monitoring and checklist issue, rather than a procedure prescribed by CAT.OP.MPA.185. A discrepancy does not justify inventing a universal checklist or abandoning the immediate landing decision.
A useful mental-maths follow-up: if the 1,200 kg reserve represents 30 minutes at a constant holding fuel flow, 200 kg represents roughly five minutes at that same flow. That assumption does not turn the 200 kg margin into five minutes of actual endurance in every configuration. Practise the calculation with the fuel and time questions.
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Model answer: MINIMUM FUEL
For the first row, answer as the pilot monitoring (PM) in a two-pilot crew:
“The commander has committed to this aerodrome. We predict 1,400 kg on landing. A further 250 kg would leave 1,150 kg, below our 1,200 kg reserve. The commander declares MINIMUM FUEL, and as PM I'd transmit under our SOP: ‘Approach, XYZ123, MINIMUM FUEL.’ The pilot flying (PF) maintains the flight path while I keep the landing forecast current and flag any change that requires escalation.”
Under SERA.11012(a), ATC must advise, as soon as practicable, of anticipated delays or that none are expected. MINIMUM FUEL gives no priority. Reassess immediately if ATC issues a clearance that would put the landing prediction below final reserve. If the forecast at the nearest safe landing aerodrome is below reserve, make the distress call.
Model answer: MAYDAY FUEL
For the second row:
“At the nearest aerodrome where we can land safely, we predict 1,100 kg against a 1,200 kg final reserve. The commander declares the emergency immediately. As PM, I'd transmit under our SOP: ‘MAYDAY MAYDAY MAYDAY FUEL, Approach, XYZ123, request direct [aerodrome] for runway [XX], [position], [level], heading [XXX].’ The PF maintains the flight path while I handle the radio and support the landing plan.”
SERA.14095(b)(1) calls for as many distress-message elements as possible: the ATS unit, aircraft identity, nature of the distress, intentions, position, level and heading. The bracketed values above must be replaced with the actual situation.
When available, give estimated endurance in minutes based on current usable fuel and expected burn, and the number of persons on board as useful supplementary information or when requested. For transponder selection, SERA.13005(a)(1) requires 7700 unless ATC has previously directed the pilot to operate on a specified code; it still permits selecting 7700 when there is a particular reason to consider that the best course. Brief the cabin crew and assess every feasible safe-landing option, including options the operator would not normally use. These supporting actions must not delay the distress call. Endurance, persons on board and 7700 are not additional mandatory items in the SERA.14095(b)(1)(ii) message list.
Say both answers aloud in the AI video interview simulator.
How does the FAA minimum fuel advisory differ?
FAA AIM 5-5-15 describes minimum fuel as advice that, on reaching destination, the aircraft cannot accept undue delay. It is neither an emergency nor a request for traffic priority. If the remaining usable fuel makes priority necessary for a safe landing, declare an emergency due to low fuel and report the fuel remaining in minutes.
The common lesson is to communicate the actual need clearly. Do not transfer the EASA CAT final-reserve trigger into a US answer without first identifying the rules and procedures that apply.
Follow-up questions with short answers
- Which landing option does your forecast refer to? Name the aerodrome and the route used for the prediction; the EASA emergency test uses the nearest aerodrome where a safe landing can be made.
- What changes if ATC adds a delay? Update consumption and landing fuel, then reassess the continue-or-divert decision and declaration.
- Why is tank quantity different from landing fuel? Fuel still has to be used to reach, approach and land at the chosen option; a diversion or go-around can change that requirement.
- Which call fits the first row? MINIMUM FUEL: the crew is committed and a further change may put landing fuel below reserve, although the present prediction remains above it.
- Which call fits the second row? MAYDAY MAYDAY MAYDAY FUEL: the prediction at the nearest safe landing option is already below reserve.
- What do you verify outside EASA? Identify the jurisdiction, operation and operator policy. In US airspace, AIM 5-5-15 uses the minimum-fuel advisory and the low-fuel emergency/remaining-minutes explanation above.
Sources and scope
The primary references are EASA Air Operations, CAT.OP.MPA.181(c)(5), GM1 CAT.OP.MPA.181(i), CAT.OP.MPA.185(b)–(d), AMC1 CAT.OP.MPA.185(a)(b)(2) and GM1 CAT.OP.MPA.185(d)–(k); EASA SERA, SERA.11012, SERA.13005(a)(1) and SERA.14095; the FAA AIM paragraph linked above; and Airbus's type-specific fuel-monitoring example. In SERA airspace, SERA.11012(b) specifies MAYDAY, preferably repeated three times, followed by FUEL; the CAT declaration is written out in full above.
For connected practice, review air-law questions, unstable approach decisions and the EU SERA lost-communications example.
Last reviewed: November 2026
Your next fuel interview practice session
Cover the explanation column, state the landing prediction and make the radio call. Ask a partner to add a delay or change the runway, then explain what you would reassess.
Start with the free pilot interview questions or download the existing free 20-question PDF. For technical questions with model answers and spoken practice in the video interview simulator, compare YPI passes. Independent preparation resource, not affiliated with or endorsed by any airline.
