Resupplying the High Observation Post
Your battalion holds an observation post at 3,600 m. The post is manned by 40 soldiers for a 20-day rotation. Ground resupply by mule track takes 9 hours each way, and engineers assess the track as impassable on 3 days in 10 because of the slide zone. Helicopter resupply is available from one aircraft, with 6 flying hours per day for this task and 2.5 flying hours per sortie to the post and back. Effective payload is 700 kg per sortie after fuel and temperature penalties at that altitude. Planning factors: 1.9 kg of rations per soldier per day; 0.8 kg per litre of kerosene; 240 litres of kerosene for cooking and the generator over the rotation; a 15 per cent reserve on rations only. Water is not lifted - it comes from snow melt and filters. The forecast gives a 30 per cent chance of a no-fly day in any given 24 hours.
1. Compute the total lift required and the minimum number of sorties. Show every step.
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Step 1 - rations. 40 soldiers x 20 days x 1.9 kg = 1,520 kg.
Step 2 - ration reserve. The 15 per cent applies to rations only, not to kerosene: 1,520 x 1.15 = 1,748 kg.
Step 3 - kerosene. 240 litres x 0.8 kg per litre = 192 kg.
Step 4 - total. 1,748 + 192 = 1,940 kg.
Step 5 - sorties. 1,940 / 700 = 2.77. Round up to 3 sorties, because the airframe time for a partial load is the same as for a full one: splitting the third sortie into two does not save anything and doubles the risk exposure.
Step 6 - flying hours. 3 x 2.5 = 7.5 hours, against 6 hours available on a normal day.
Two checks I would state rather than skip. Water is not lifted, but 40 soldiers at 6 litres a day for 20 days is 4,800 litres from melt - that is a medical and engineering question, not a logistics one, and if the melt source is unreliable the whole weight calculation changes. Second, the 700 kg payload is an altitude-dependent figure; if the aircraft changes type, replan from the new figure rather than scaling the old one.
2. The aviation officer can give 6 flying hours on day 1 and 2.5 hours on day 2. Assess whether the plan survives, and quantify the risk.
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Capacity against demand. Day 1: 6 / 2.5 = 2.4, so 2 sorties (5 hours used; the spare hour cannot make a third sortie). Day 2: 2.5 hours, so 1 sortie. Total 3 sorties, 2,100 kg of capacity against 1,940 kg required - 160 kg of slack, roughly two days of rations for 40 soldiers.
The plan works only if all three lifts happen. With a 30 per cent chance of a no-fly day, the probability that both flying days are usable is 0.7 x 0.7 = 0.49. That is the number to put in front of the commanding officer, but not on its own - probability without consequence is not a decision.
Consequence. If one sortie is lost, delivered weight is 1,400 kg against 1,940 kg required: a shortfall of 540 kg. At 1.9 kg per soldier per day, 540 / (1.9 x 40) = 7.1 days of rations missing. The post runs short around day 13 of a 20-day rotation. If the lost sortie is the kerosene one, the post keeps its food and loses cooking and generator power, which at 3,600 m in this season is the more dangerous failure.
So the correct statement is not '49 per cent risk' but 'a coin-flip chance of seven days without rations'. Those two sentences lead to different decisions.
3. Choose one mitigation, cost it, and explain why you rejected the other three.
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Options tested.
- Cut the reserve from 15 per cent to zero. Saves 228 kg. Not enough to remove a sortie, and it destroys the margin that exists precisely for weather. Reject.
- Reduce the post to 30 soldiers. Rations 30 x 20 x 1.9 x 1.15 = 1,311 kg, plus 192 kg kerosene = 1,503 kg. 1,503 / 700 = 2.15, still 3 sorties. The saving buys nothing and costs a third of the observation. Reject on arithmetic, not on tactics.
- Ask for 8.5 hours on day 1 (3 sorties in one day). Full delivery then needs only one flyable day, probability 0.7 - better than 0.49, but it asks for 7.5 flying hours and pushes crew duty limits, and a single unserviceability still strands the post. Keep as a fallback, not the plan.
- Recommended: ground pre-positioning. Move 540 kg - the exact one-sortie shortfall - to the near side of the slide zone using the 7 good days in 10, before the flying window opens. Cost: about 6 mule-days and a 4-soldier escort. This converts a coin-flip on seven days of hunger into a coin-flip on a nine-hour carry, and it touches neither the reserve nor the airframe.
One honest adjustment: the escort eats from the same stock, so add 4 x 6 x 1.9 = 46 kg to the pre-positioned load. Plans that forget the porters are how the reserve quietly disappears.