Qantas Delays/Cancellations

[jb747]

Yeah understand about headwinds and tailwinds. Are you saying that when you set a speed on a plane, it's not determined by, say for example engine revs, but the plane attempts to maintain a ground speed? Feel like a complete nonce because that makes no sense to me.

Normally an aircraft is flown at a mach number or indicated airspeed. Both are used, with a changeover at about FL300. There is a maximum mach number, and the aircraft is actually flown quite close to that number. The resultant ground speed is simply accepted...

There is an FMC mode in which the aircraft will attempt to maintain a targeted ETA. It's called RTA progress, and the FMC will command varying airspeeds in an attempt to maintain that ETA. It's not used much, as it can choose speeds that are faster or slower than we are comfortable with, it can be very thirsty, and it stops the FMC from making valid predictions about fuel usage.

 

[jb747]

These two statements seem to contradict each other? On the one hand you say you can't exceed a speed in case the winds take you over max. On the other, you say winds are the best way to go fast.

When the wind changes, as it's doing any time that you feel any bumps, the airspeed may, for a short period, increase or decrease. For instance, if you're heading east (on your Perth trip), and you suddenly run into an air mass that's moving east at 100 knots (and this is exactly what happens as you climb out of Perth), you'll find that the airspeed will decay, and you'll have to stop the climb to get that speed back. For that reason, it was common to fly that climb at quite high speed...knowing that you'll lose speed when you find the jet stream. Your groundspeed will increase, but that's not what makes the aircraft fly. Going the other way, you can climb into that jet stream, and it will suddenly be a big increase in the wind on the nose, and the IAS will spike upwards...so much so that idle thrust and even speed brakes can be needed to contain the speed....

So, the issue is that wind changes (which acquire the name 'wind shear' when near the ground) can cause the IAS to spike for short periods. If you don't have much margin below your maximum speed, then that spike may take you over the max.

I was once on a PER-MEL flight (cannot remember if 737 or A330) and there were audible gasps throughout the plane when the Capt announced out arrival time, because it would mean our flight time was just over 2.5 hours. I'm willing to concede I'd had a few wines, but everyone else in the plane could not believe it as well. Is that even possible?

2:30 flight time isn't that uncommon. By the time you add in the taxi time at each end, the chock to chock time will be about 2:45. That's an average groundspeed of about 580 knots. I've seen over 700 a couple of times, and above 650 many times on that route.

 

[moa999]

2:30 flight time isn't that uncommon. By the time you add in the taxi time at each end, the chock to chock time will be about 2:45. That's an average groundspeed of about 580 knots. I've seen over 700 a couple of times, and above 650 many times on that route.

And thats why the red-eyes back from PER can be hellish for pax when you get the winds

 

[Melburnian1]

While QF12 will be late into SYD on Tuesday 5 July 2016 as noted above, this should not delay the returning A388 on QF11 from SYD to LAX as it is being formed by QF8 from DFW that arrived 25 minutes late at 0630 hours.

Passengers on QF15 from BNE to LAX (B744) are not quite so fortunate, as it is expected to depart 45 minutes tardy at 1045 due to the late arrival of QF16 ex LAX as also noted above. QF suggests that QF15 should arrive in LAX on time, and therefore hopefully not be delayed on its transcontinental USA 'tag flight'.

QF403, the 0645 hours SYD - MEL, has been cancelled as has QF407, the 0715 hours southbound.

 

[Himeno]

QF12 departed JFK about 1 hour late (Mon 4). Arrived LAX only a few minutes behind schedule. The 747 is currently taxing to the gate. OQC and OQD were towed over to the gates shortly before OEG touched down.

Looks like all 3 flights will depart LAX on time tonight.

 

[suze2000]

2:30 flight time isn't that uncommon. By the time you add in the taxi time at each end, the chock to chock time will be about 2:45. That's an average groundspeed of about 580 knots. I've seen over 700 a couple of times, and above 650 many times on that route.

Well I think it was gate-to-gate, but I just remember being super happy I was going to get home an hour earlier than expected. Thanks for answering all my questions.

 

[Melburnian1]

Tuesday 5 July saw QF129, the SYD - PVG that is due out at 0935 hours depart instead at 1011 for a suggested 80 minute late arrival tonight at 1950 hours. This will delay QF130 from PVG back to SYD.

 

[MEL_Traveller]

What is SIA doing/not doing that QF is not?

It's not an apples and apples comparison. QF35 is a 330, whilst the SQ flights are 777 and 380.

Lol - this. I was thinking SQ must be using Airbus.

you know what they say - Airbus... the only aircraft that can suffer bird strike... from the rear :mrgreen:

 

[Melburnian1]

With the wet conditions in MEL on the evening of Tuesday 5 July, quite a few aircraft are in a holding pattern with QF479's B&38 VH-VXS no exception. This 1845 hours flight took off from SYD at 1922 and is expected to arrive in MEL at around 2051, 31 minutes late.

 

[Himeno]

or not...
QF12 (mon) took off at midnight after waiting for 70 pax and bags from transcon and long taxi to runway.

arrived SYD 0730 wed.
missed my connection. moved to a coughpy dash 8 from the nice 717

 

[jb747]

Lol - this. I was thinking SQ must be using Airbus.

you know what they say - Airbus... the only aircraft that can suffer bird strike... from the rear :mrgreen:

Said Boeing pilots...

I think the 310 and 300 may have been slower than the MD11/747, but the current batch fit in pretty well with the speed of the masses. The 737 is about the slowest thing around. 767 was generally planned at about .79.

 

[suze2000]

or not...
QF12 (mon) took off at midnight after waiting for 70 pax and bags from transcon and long taxi to runway.

Commiserations. It's a frustrating long taxi, for sure. It's also pretty bad to be sitting on the plane thinking you've struck it lucky and the seat next to you is empty, only to have it filled as the doors closed.

 

[Melburnian1]

On Wednesday 6 July, QF447 (1600 hours SYD down to MEL) took off at 1632 which is only about 15 minutes late, but is likely to arrive at about 1807, 32 minutes late in the shape of B738 VH-XZI.

Tuesday 5 July's QF12 departed LAX at 2315, 45 minutes behind time with its Thursday morning, 7 July arrival expected at 0700, half an hour tardy.

On Wednesday 6 July, QF19 departed SYD 55 minutes late at 1305 with MNL arrival expected at 1930, an hour late. QF20 should depart back to SYD about 40 minutes late if past practice is any guide.

The HKG-bound second QF flight of the day (QF117) pushed back 41 minutes tardy at 1256 with arrival suggested as 2035, 55 minutes late.

Earlier, the BNE - LAX B744, QF15 departed 63 minutes late at 1113 with predicted at gate arrival as 0630, half an hour late and hence a 43 minute gain on the timetable should it occur.

Also on 6 July but in the evening, due to delays in MEL (earlier rain), QF478, the 1845 hours MEL - SYD was not airborne until 2002 with B738 VH-VZD sugegsted as arriving at about 2106 hours, 56 minutes late.

While the MEL - HKG QF29 only departed 18 minutes behind the schedule at 1038, it is not expected to arrive until 1840, 40 minutes late. Similarly QF35 (1145 MEL - SIN) departed 23 minutes late at 1208, but should be 40 minutes late on blocks at the terminal at a projected 1835 hours.

 

[Melburnian1]

QF118 is arriving in SYD at about 0935, 35 minutes late on Thursday 7 July as A333 VH-QPE did not take off from HKG on 6 July until 2238 despite its pushback time of 2135 hours.

The 0930 MEL - SYD (QF420, VH-EBS, an A332) took off at 1045 and is arriving at 1200, 65 minutes behind time.

QF509, the 0825 BNE down to SYD, took off at 1035, arriving at about 1155, an hour and 54 minutes late. Aircraft was A332 VH-EBD.

The 1130 hours MEL - SYD took off at 1245 - an identical delay to QF420 above - and arrived at about 1355, an hour late. Aircraft was A332 VH-EBV.

Southbound, QF435 (1300 hours SYD - MEL) took off at 1400, with expected aeeival of B738 VH-VYI at 1525, 50 minutes late, so quite a few badly delayed flights on Australia's busiest air route today.

 

[Melburnian1]

Continuing the delay theme for Thursday 7 July but this time during the evening, QF441, the 1430 hours mid afternoon SUD - MEL must have earlier failed as B738 VH-VZT took off about 240 minutes behind schedule at 1845 with arrival suggested as 1949, 234 minutes late. A shocking performance but hopefully any passengers with 'status' were transferred to other flights.

 

[milehighclub]

Lots of weather issues today for both SYD and MEL.

 

[Melburnian1]

Lots of weather issues today for both SYD and MEL.

milehighclub, yes, I assumed that, but elsewhere in Melbourne, while a very dull day, it's nothing exceptional for winter. There's been about 14 millimetres of rain at Sydney Airport between 0900 and 2100, and a smattering of rain at MEL, with both having quite high humidity (although not 100 per cent). Has this led to low visibility for approaching aircraft, slowing things down?

A332 VH-EBK on the 2030 hours QF653 MEL to PER (Thursday 7 July) was airborne at 2118 with arrival forecast for 2320 hours, 35 minutes late.

 

[Mattg]

I was in SCL on Tuesday afternoon (5 July) watching VH-OJM as she sat on the ground going nowhere for hours. QF28 (scheduled 13:30 departure) was originally delayed by a bit over an hour. It then left the gate, sat on the tarmac short of the runway for about another hour, and returned to the gate. When my flight (also delayed) eventually left around 7pm, QF28 was still sitting at the gate with passengers on board. No idea when it eventually departed, but I believe the delay was due to a mechanical issue.

 

[Melburnian1]

There is a media report on 'The Age' website indicating that single runway operations were in place at Melbourne for much of Thursday due to rain and low cloud but as at 0800 on Friday operations were less constricted. There is comment in the article that QF's Thursday throughput was 18 domestic flights an hour not the usual 25.

Mattg, many thanks for your on-the-spot report. Looking it up, QF28 (the 1330 Tuesday 5 July SCL - SYD) eventually departed not on Tuesday but on Wednesday 6 late afternoon at 1744, arriving in SYD at 2130 on Thursday 7 July instead of its scheduled arrival at 1745 hours on Wednesday.

QF75 on Thursday 7 July departed SYD 57 minutes late at 1757, arriving YVR at 1447, 42 minutes behind.

Friday 8 July has seen QF415 (0800 SYD down to MEL) departing at 0832 with arrival likely at 0955, 20 minutes behind the timetable.

The 0810 hours SYD to WTB (QF2016) should depart at 0850 instead of 0810 hours.

QF7940 and QF7942 (both 0930 hours SYD to LDH) have each got the boot.

 

[Melburnian1]

On Friday 8 July 2016, QF19 (1210 SYD - MNL) departed at 1247 with arrival expected half an hour late at 1900. This will marginally delay QF20 as what often occurs is that the arruval time for QF19 turns out to be unrealistic due to congestion in the air on approach to this airport that only seems able to handle about 40 movements an hour at the best of times, yet like a fair bit of Asia has had a large increase in passengers and flights in the last decade.

While QF23 was just 24 minutes late pushing back for BKK in SYD at 1014, its arrival is not suggested until 1720, 40 minutes tardy.

QF81, the 1020 from SYD up to SIN did not push back until 1118, so arrival is forecast for 1750 hours, 65 minutes late.

The 1005 hours SYD - HKG QF127 was similar in that it departed 63 minutes behind at 1108, arrival being suggested as 1805, 45 minutes tardy.

QF27 (1230 SYD to SCL B744 flight) departed 45 minutes tardy at 1315. It should arrive 40 minutes down at 1150 same day.

The Thursday 7 July QF2 had a normal run from LHR to DXB, departing twelve minutes late at 2142 and on Friday 8 July arriving nine minutes early at 0721 hours, but then instead of pushing back at 0915 hours it did so at 1106 meaning a predicted Saturday 9 July arrival time of 0615 instead of 0510. If this holds true it will mean that between DXB and SYD, QF2 will have beaten the gate-to-gate timetable by 46 minutes.

QF765 from SYD to ADL this afternoon took off at 1743 despite a departure time of 1640; B738 VH-XZH should arrive at about 1906 hours, 46 minutes behind the schedule.

QF1536 (1745 hours MEL to CBR) was airborne at 1830. B717 VH-YQW should arrive at about 1919 hours, 29 minutes late.