Flight time calculation doesn't equal flight time listed...
 

I am trying to plan my first overseas trip and am stuck with flight time calculations.


Listed Flight Time : 10 hours 45 minutes

Listed Departure Time : 6:00pm Sydney Time (30th August 2013)
Listed Arrival Time : 7:45am Honolulu Time (30th August 2013)


I converted to UTC/GMT time so I'm comparing apples with apples:

Sydney is UTC +10... so Departure Time is 8:00am UTC (30th August)
Honolulu is UTC -10... so Arrival Time is 5:45pm UTC (30th August)


I make that a difference of 9 hours and 45 minutes.

So, they are listing a flight time of 10 hours and 45 minutes... but when I am doing the calculation on their departure and arrival times I get 9 hours and 45 minutes.


Hawaii doesn't do daylight savings time so it will stay UTC -10. Sydney doesn't start daylight savings till October... it will be UTC +10 for quite some time.

In other words I can't see any complications regarding time zones changing mid flight.



When I do the calculation on the return flight I don't have any discrepancy... they list the flight time as 10 hours and 35 minutes... and when I calculate the flight time using the departure and arrival and the same method above, I also get 10 hours and 35 minutes.

It seems a wild claim to say they have a flaw in their itinerary calculation system, so I'm trying to rule out where I'm going wrong before I make that claim.

Cross checking for the flight times to Hawaii from Sydney I find that about 10 hours 38 minutes is right.... which is in line with their listed flight time of 10 hours and 45 minutes (source: http://www.travelmath.com/flying-tim...alia/to/Hawaii)

This discrepancy showed itself when I started making a spreadsheet to plan my itinerary... and planning bookings for connecting flights when I land... hence the concern that if they have a mistake in the itinerary then I'll miss a connecting flight because I'll arrive an hour later than they suggest!

Schedule Padding?
 

Maybe it's some sort of padding in the schedule to make sure the flight arrives on tine. This is a guess based on my experience riding trains. The railroad typically adds padding at the end of the trip that allows a late train to make up time.

Welcome to FT!

Assuming you are referring to the JQ flight, its actual scheduled duration is 9 hrs 45 mins:

[KVS Availability Tool 7.2.4/Diamond - Timetable/NL]

I'm assuming you're on JQ3. On the Qantas website it is listed as 9 hr 45 duration and all other details the same as what you gave. So nothing to worry about.
BTW, due to winds it is not uncommon for one direction to be quicker than the other.

Ya, I noticed this a while back too. Seems to me they're trying to account for taxiing/airport mush at that time/who knows what. My recent BTV-JFK flight was listed as being around 1.5 hours, but the actual flight duration was 55 minutes.