4 ms·

It's not poor scheduling, so much as Heathrow being at 99.5% capacity which means queuing is required so they can maintain one landing per minute.

by robjan 8y ago

CydeWeys 8y ago
Yeah, the airport is at capacity. I'm not seeing how it has anything to do with schedule padding at all. They're doing take-offs and landings there as quickly as possible.
- jillesvangurp 8y ago
  Airlines know before they take off their ETA to the other side pretty much down to the minute. Their planning builds in padding so that they are guaranteed to make it on time. Which means they expect to arrive early and end up in a holding pattern because the take off slot and landing slot are deliberately misaligned. This is exactly what the article is implying. That's of course aside from the inevitable issues arising from operating at 99% capacity. Anyone familiar with queuing theory or logistics knows that this just means things pile up at the cost of delays and extra fuel being burnt. So, that too is poor planning. You never operate systems with queues at close to 100% capacity unless you are looking for severe cost overruns and bottlenecks. This poor planning results from misaligned incentives. Airports can just park planes in holding patterns for however long they desire. It's not their fuel being burnt. So they over provision knowing full well they will have planes in holding patterns throughout the day, This maximizes their revenue. So they are actively incentivized to do this. Likewise, airlines buy fuel cheaply and only get penalized for being late. So they are incentivized to implement padding. So, the fix is re-aligning the incentives for airports and airlines to minimize planes in holding patterns and fuel being burnt. There are several ways to do this but the bottom line would be making sure both airlines and airports aim to not have planes in holding patterns because that costs both of them something.

It's not poor scheduling, so much as Heathrow being at 99.5% capacity which means queuing is required so they can maintain one landing per minute.

by robjan 8y ago

It's not poor scheduling, so much as Heathrow being at 99.5% capacity which means queuing is required so they can maintain one landing per minute.

CydeWeys 8y ago

Yeah, the airport is at capacity. I'm not seeing how it has anything to do with schedule padding at all. They're doing take-offs and landings there as quickly as possible.

jillesvangurp 8y ago
Airlines know before they take off their ETA to the other side pretty much down to the minute. Their planning builds in padding so that they are guaranteed to make it on time. Which means they expect to arrive early and end up in a holding pattern because the take off slot and landing slot are deliberately misaligned. This is exactly what the article is implying. That's of course aside from the inevitable issues arising from operating at 99% capacity. Anyone familiar with queuing theory or logistics knows that this just means things pile up at the cost of delays and extra fuel being burnt. So, that too is poor planning. You never operate systems with queues at close to 100% capacity unless you are looking for severe cost overruns and bottlenecks. This poor planning results from misaligned incentives. Airports can just park planes in holding patterns for however long they desire. It's not their fuel being burnt. So they over provision knowing full well they will have planes in holding patterns throughout the day, This maximizes their revenue. So they are actively incentivized to do this. Likewise, airlines buy fuel cheaply and only get penalized for being late. So they are incentivized to implement padding. So, the fix is re-aligning the incentives for airports and airlines to minimize planes in holding patterns and fuel being burnt. There are several ways to do this but the bottom line would be making sure both airlines and airports aim to not have planes in holding patterns because that costs both of them something.