Welcome Back to JFK

QF45 is scheduled to leave at 0715. We picked up our boarding passes at the gate at 0630 as instructed. I then went back to duty free to look for some prices for Sarah’s brother. We were at gate 36, as far as possible without falling off the terminal, so Sarah stayed at the gate. By the time I got back, it was 0645 and they were doing a final call. Very Sarah!

Everybody on board soon after, but the door didn’t close for a while. Off blox at 0712. Sarah would be proud. Not really, no.

Taxi to the runway. We took the scenic route, via Circular Quay. Didn’t see the Opera house or the bridge. Must have been on the other side of the aircraft.

E V E N T U A L L Y made it onto the runway at 0804. Airborne by 0805. OMG. 53 minutes. Reminds me of the JFK taxi a few nights ago.

The mind tends to wander while waiting this long for takeoff. While watching the choppy waves out the window, I started thinking about weight calculations. Yes. I know!

Anyway, I never wanted to learn Loadsheet, but I do know that there is a complicated calculation for fuel consumption during a flight. Same goes for any weight-critical vehicle or vessel. It goes something like this:

• The aircraft has a particular distance to travel.
• The aircraft at takeoff is a particular weight.
• To move an aircraft of that weight that distance, takes a particular quantity of fuel.
• That fuel has a particular weight, which is added to the total weight of the aircraft.
• During the flight, fuel is consumed at a particular rate, so that there is only a (much smaller) particular quantity of fuel left on arrival.
• As a result, the aircraft is getting lighter as it travels.
• As the aircraft gets lighter, it can travel further on the fuel it carries, reducing its consumption rate.

Once upon a time, somebody did the maths on this reducing fuel requirement, so that the calculation for the Loadsheet is both fast and accurate.

This type of calculation applies to other things too.

Think about the ice that a long-haul aircraft carries onboard.

• There are a set number of pax onboard.
• Each pax will be offered a set number of drinks during the flight.
• Each drink will require a quantity of ice.

Simple enough so far?

• But ice melts. If it is not refrigerated, the total volume of ice will reduce at a particular rate, for the duration of the flight.
• So an additional quantity of ice is required, to not only keep the required ice frozen until it is consumed, but also to replace that ice which melts before it can be used.
• The ice is being reduced by 2 things during the flight. First, it is being consumed. Second, it is melting.

Again, once upon a time somebody has done the maths on how much ice needs to be loaded at the beginning of the flight, so that there is enough to consume during the flight, without running out.

Added to that, is the sheer volume of ice required for a flight of perhaps 15hrs. This volume probably has a weight that needs to be built into the fuel calculation as well. If you think about it though, the weight of the ice does not decrease over the flight.

Ice turns to water. No significant weight change. Ice gets consumed, but doesn’t actually go anywhere. Ice bag to ice bucket to glass to pax to bladder to toilet to waste tank. It never leaves the aircraft, just moves around a bit.

So the real issue is the space required to store the ice. Because storage required more ice than will be consumed, there is an opportunity for weight saving.

What if we had icemakers onboard? They would take up perhaps the space of an onboard oven or storage tank, perhaps less. They would be attached to the potable water supply, so would be using water that is onboard anyway. They would make ice on an as-needs basis, so there is no ice storage required. Mmmm.