Qantas's Project Sunrise: Heathrow slots & Sydney curfew

Project Sunrise has been in the news again with Qantas updating us on their plans to start non-stop flights from Sydney to London and New York. With the first A350-1000 scheduled for delivery in late 2026 it is anticipated that the first Project Sunrise route will start after the third aircraft arrives in early 2027. This will give Qantas time to overcome typical entry into service challenges associated with any new aircraft type and generate sufficient scheduling redundancy.

The Sydney-London route is the most intriguing given the unique operational constraints that slots and curfews generate at both Sydney and London Heathrow. Amongst all the fanfare of Project Sunrise this is an interesting challenge that hasn’t received much attention! Let’s consider the implications in more detail and have a look at how Qantas might design the schedules.

Qantas’s London operations

Qantas currently operate two daily flights to London Heathrow, one from Sydney via Singapore (QF1/2) and another non-stop from Perth (QF9/10). Both flights have early morning arrivals slots at Heathrow, while the return flights vary significantly with the Perth flight leaving London at midday while the Sydney flights leaves in the evening. There are minor variations between the timings for the northern summer (NS) and winter (NW) scheduling seasons.

Northern Summer:

QF1  SYD-SIN-LHR 14:50  6:35+1
QF9  PER-LHR     18:35  5:05+1

QF2  LHR-SIN-SYD 20:50  5:10+2
QF10 LHR-PER     11:55 11:50+1

Northern Winter:

QF1  SYD-SIN-LHR 15:55  6:15+1
QF9  PER-LHR     19:15  5:05+1

QF2  LHR-SIN-SYD 20:10  6:30+2
QF10 LHR-PER     11:50 12:20+1

Qantas’s Heathrow configuration has been through many twists and turns in recent decades. The Perth-London non-stop is a relatively recent innovation having replaced the one-stop Melbourne-Singapore-London flight in 2018. It initially operated as Melbourne-Perth-London, however the Melbourne leg was dropped last year.

Why Qantas dropped Melbourne leg of Perth-London

Prior to that Qantas operated four daily flights to London, two from Sydney (one each via Bangkok and Singapore) and two from Melbourne (one each via Hong Kong and Singapore). In 2012, the Melbourne-Hong Kong-London and Sydney-Bangkok-London were dropped, while retaining both Singapore one-stop flights.

The unused slots weren’t sold but rather leased to British Airways. This is consequential since Qantas will need utilise these slots to operate new Project Sunrise flights. Furthermore, all indications are that the non-stop Sydney-London flight will be in addition to the existing flights and not replacing them. This doesn’t preclude the existing one-stop via Singapore being routed from a different Australian city.

The 2012 schedule gives us a glimpse at Qantas’s Heathrow slot portfolio. On the arrival side, they have three early morning slots including a prized pre-6am arrival that is currently utilised for QF9’s arrival and two post 6am slots. The 4th arrival slot is an early afternoon slot that is currently leased out to BA along with one of the morning slots.

On the departure side, they have three evening departure slots, one currently utilised by QF2 and the other two leased to BA. The 4th slot is a midday departure slot that is currently utilised by QF10.

Northern Summer:

QF9  MEL-SIN-LHR 16:30  5:40+1 (currently used for QF9)
QF29 MEL-HKG-LHR 23:50 13:30+1 (currently leased to BA)
QF31 SYD-SIN-LHR 17:10  6:35+1 (currently used for QF1)
QF1  SYD-BKK-LHR 17:55  7:00+1 (currently leased to BA)

QF10 LHR-SIN-MEL 21:30  6:00+2 (currently used for QF2)
QF30 LHR-HKG-MEL 22:30  6:55+2 (currently leased to BA)
QF32 LHR-SIN-SYD 12:05 20:20+1 (currently used for QF10)
QF2  LHR-BKK-SYD 22:15  6:15+2 (currently leased to BA)

Northern Winter:

QF9  MEL-SIN-LHR 17:00  5:25+1 (currently used for QF9)
QF29 MEL-HKG-LHR 23:55 13:30+1 (currently leased to BA)
QF31 SYD-SIN-LHR 17:30  6:20+1 (currently used for QF1)
QF1  SYD-BKK-LHR 18:05  6:25+1 (currently leased to BA)

QF10 LHR-SIN-MEL 21:30  6:30+2 (currently used for QF2)
QF30 LHR-HKG-MEL 22:30  7:50+2 (currently leased to BA)
QF32 LHR-SIN-SYD 11:05 20:35+1 (currently used for QF10)
QF2  LHR-BKK-SYD 22:10  6:55+2 (currently leased to BA)

As is well known, Heathrow’s slots are fully allocated meaning that slot times can’t be easily adjusted. Small changes in slots timings are allowed provided they fit into the rolling hourly movement limits, however significant changes require another airline to agree with swap timings. But not all Heathrow slots are equal as demand for early morning arrivals and late morning and early afternoon departures are amongst the most valuable and costly (in high demand as they’re peak time for Trans Atlantic departures).

Thus, if Qantas wanted to swap an evening departure for a midday departure they may be required to cough up money to another airline/s, just as they would having to purchase or lease new slots. Ultimately, it requires a willing buyer and willing seller! Qantas have made small changes to their slot portfolio in a number of swap transactions but the broad parameters remain the same. Now that we understand the Heathrow slot calculus, let’s play around with these slots and explore Qantas’s schedule options.

Scheduling challenges

A first consideration is estimating the block times of the non-stop Sydney-London and London-Sydney legs. The existing one-stop routings are blocked at 24:45 westbound and 23:20 eastbound, however this includes 2:10 and 2:05 ground time in Singapore. Furthermore, a more direct routing and a reduction in time lost to the additional landing and departure will cut this time even further.

Playing around with flight planning we estimated a block time of 19:40 westbound and 19:15 eastbound. However, in practice, airspace limitations, including the unavailability of Russian and Ukrainian airspace will add to this time. This may add up to an hour flying time. We haven’t included this in out calculation but one can easily add an additional hour buffer to stress test the model.

Scheduling challenge #1: curfews

Sydney has a curfew between 11pm and 6am, meaning flights can’t be scheduled to arrive or depart between these times. Flights scheduled to arrive or depart near 11pm that are delayed due to exceptional circumstances may request a curfew dispensation on the day, however this can’t be considered for scheduling purposes.

Heathrow’s curfew is a little more complex. Strictly speaking there is no curfew, however there are limits on the number of flights between 11:30pm and 6am. In practice, no departures can be scheduled between 11pm and 6am while a limited number of arrivals are allowed between 4:30am and 6am.

The table below shows all the westbound and eastbound combinations for both the NS and NW months. It highlights the limited scheduling options resultant from the curfews at both airports.

On the westbound leg, the earliest possible departure time from Sydney is 6am. This would result in a scheduled 4:40pm arrival in London in the northern summer (NS) months and 2:40pm in the northern winter (NW) months. This is estimated using a 19:40 block time, but one can add an hour if block times are padded to allow for longer flying times.

Later departures are viable through to the early afternoon. For example, a 1pm departure during NS season would be schedule to arrive in London at 11:40pm, after the curfew kicks in. However, in the NW, the window for Sydney departures is extended two more hours. The scheduling window reopens at around 7pm during NS and 9pm during NS, resulting in a morning arrival at Heathrow.

Similarly, on the return legs daytime departures from Heathrow would be viable as they’ll arrive in Sydney before curfew. However, evening departures will run up against the curfew. For example, in NS, a 7pm departure will arrive in Sydney at 11:15pm, while this barrier shifts two hours earlier in NW.

Scheduling challenge #2: slots

The second scheduling challenge we must consider is Qantas’s current slot portfolio. Early evening departures from Sydney will line up well as an early morning arrival into Heathrow and utilise the existing morning arrival slots. For example, 8pm departure from Sydney will arrive at 6:40am in NS and utilise an existing slot. For NW, the departure would shift to 10pm for a similarly timed arrival.

Utilising the midday arrival slot currently leased to BA would be impossible since this would necessitate a post curfew departure from Sydney (2am or 4am depending on the season). So it shouldn’t be controversial to assume that Qantas is likely to pick a evening departure from Sydney on the westbound leg, however the return flight is more complicated.

Utilising the existing evening departure slots from London would run into curfew issues at Sydney again. For example, in the northern summer months a 7pm or later departure would arrive in Sydney at 11:15pm or later. In the northern winter months the constraint is pulled 2 hours earlier. Even a very late departure, say 10:55pm wouldn’t arrive in Sydney before 6am. Even if one padded the block time and ensured a 6am arrival it wouldn’t likely make sense to operate this flight only in the NS. So what do Qantas do? Enter some scheduling magic!

Scheduling magic

We suspect that Qantas will cannibalise QF10’s late morning/early afternoon departure slot (11:55am in NS and 11:50am in NS). Utilising this for a non-stop to Sydney would generate a scheduled arrival time of 4:10pm and 6:05pm in NS and NW, respectively. This is a workable arrival time in Sydney allowing ample domestic connections and even onward connections to New Zealand.

But what about QF10? QF10 will in turn have to be rescheduled to utilise an evening departure slot, resulting in an evening arrival at Perth instead of the current midday arrival. For example, an 8pm departure from Heathrow would get it into Perth at 8:05pm and 8:30pm in NS and NW seasons, respectively.

However, this comes with a cost. Firstly, it would require a significantly longer turnaround time at Heathrow with the aircraft spending approximately 14 hours on the ground and generating a significant reduction in utilisation. Secondly, the later arrival into Perth would reduce the availability of onward connections and turn the remaining connecting options into redeye flights. Connecting options lost would include Adelaide and Canberra, however they will still be available through Sydney limiting the impact of the schedule change somewhat.

There’s no such thing as a free lunch

As is evident from the discussion scheduling ultra long haul flights has its challenges. In this case it’s made worse by both airports having unique operating constraints. Furthermore, scheduling the Sydney flights may require a reorganisation of Qantas’s existing flights and generate trade-offs that will undermine aircraft utilisation and reducing network efficient of one flight to allow another.

However, this can be avoided by swapping or acquiring another afternoon slot. This is easier said than done and may result in a substantial price to be paid, even if you can find a willing seller!

So what do you think? Will Qantas open their wallet? Or will they cannibalise the Perth slots?