Caticlan Payload–Fuel Conflict on an ATR 72-600
An ATR 72-600 is scheduled RPLL–RPVE (Manila–Caticlan) with 68 passengers, 850 kg of checked bags and 400 kg of cargo. DOW is 13,600 kg; MTOW 22,800 kg; MLW 21,000 kg; MZFW 20,400 kg. Standard passenger mass is 75 kg. The fuel plan uses 150 kg taxi, 2,900 kg trip, 5% trip contingency, 650 kg to alternate RPVK (Kalibo), 45 minutes final reserve at 900 kg/h, and 300 kg additional. Caticlan forecast is 32°C, wind calm; no destination fuel is available. The dispatcher notices the load sheet shows TOW 24,800 kg and the crew asks whether to depart with less fuel and refuel at Kalibo after the diversion. Company policy requires all planned fuel to be on board at departure. No MEL items affect fuel. The runway is not limiting.
1. Compute the minimum block fuel and the maximum payload permitted by MTOW. Can the flight depart as loaded?
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Minimum block fuel is the sum of all planned fuel:
- Taxi: 150 kg
- Trip: 2,900 kg
- Contingency: 5% × 2,900 = 145 kg
- Alternate to RPVK: 650 kg
- Final reserve: 45 min × 900 kg/h = 675 kg
- Additional: 300 kg
Total = 150 + 2,900 + 145 + 650 + 675 + 300 = 4,820 kg.
Payload = 68 × 75 = 5,100 kg passengers + 850 kg bags + 400 kg cargo = 6,350 kg. ZFW = 13,600 + 6,350 = 19,950 kg, which is below MZFW 20,400 kg.
TOW with planned fuel = 19,950 + 4,820 = 24,770 kg, about 1,970 kg above MTOW 22,800 kg. Maximum payload at MTOW with the required fuel = 22,800 − 13,600 − 4,820 = 4,380 kg. Therefore the flight cannot depart as loaded; at least 1,970 kg of payload must be removed. Landing weight after trip fuel would be 22,800 − 2,900 = 19,900 kg, below MLW, so the problem is takeoff weight, not landing weight.
2. The crew proposes taking 2,850 kg of fuel and refuelling at Kalibo after diversion. Evaluate this proposal against the fuel plan and company policy. What would you authorize?
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Reject the proposal. With only 2,850 kg, the aircraft would not have enough fuel even for taxi, trip and contingency: 150 + 2,900 + 145 = 3,195 kg. It certainly could not carry alternate fuel and final reserve. Refuelling after a diversion is not a substitute for planned reserve fuel; final reserve must remain intact and must not be planned for use. Company policy also requires all planned fuel on board at departure.
The legal minimum remains 4,820 kg. If the 300 kg additional fuel is genuinely discretionary and not needed for expected holding or weather, it could be removed, reducing required fuel to 4,520 kg. Then maximum payload becomes 22,800 − 13,600 − 4,520 = 4,680 kg, still requiring an offload of 1,670 kg. Otherwise the full 1,970 kg offload is required. Authorize departure only after a revised load sheet shows TOW ≤ 22,800 kg, ZFW ≤ 20,400 kg and landing weight ≤ 21,000 kg. A technical stop or splitting the load is preferable to reducing reserve fuel.
3. If no cargo or bags are removed, how many passengers must be offloaded at 75 kg each, and what checks close the load control loop?
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Required reduction is 1,970 kg. At 75 kg per passenger, 1,970 ÷ 75 = 26.27, so 27 passengers must be offloaded. Offloading 26 passengers removes only 1,950 kg and leaves TOW at 22,820 kg, still 20 kg over MTOW. Offloading 27 removes 2,025 kg, giving payload 4,325 kg, ZFW 17,925 kg and TOW 22,745 kg.
After the change, issue a new load sheet and verify ZFW, TOW and landing weight against limits. Check the CG remains inside the envelope, revise seat allocation and baggage reconciliation, confirm the actual passenger count, and notify operations and the crew. If the 300 kg additional fuel was removed, recalculate fuel and repeat the weight checks. The aim is a documented, cross-checked load sheet before departure, not an informal verbal estimate.