Flight Time Differences
 

can someone tell me why there is a difference in actual flight times.
AirCanada London UK to Calgary AB - flight time is 8:30
AirTransat London to Calgary - flight time 9:35
Both are direct flights, doesn't make sense to me.

Some carriers build in a little more contingency than others. That and some aeroplanes are a little faster than others. But it's usually the former.

While London Elite pretty much hit the nail right on the head with that answer one additional factor is airport. AC flies from LHR & TS flies from LGW. Each will have their own route over different areas and avoiding traffic from both airports. But mostly it probably has to do with padding times.

Please follow the redirects as this moves to TravelBuzz.

~beckoa, co-moderator Information Desk

Departure time and arrival time as quoted by airlines is departure from and arrival to the gate, not just flying time once airborne. The amount of time allocated for taxi, waiting to take off, waiting for an arrival gate, etc can be substantial especially when you are talking about congested airports which most of the major international hubs are. Also long haul flight times can be affected by time of year and typical winds. For all of these reasons the posted flight schedule includes a discretionary amount of "padding" on top of the actual flight duration. It's most obvious on very short flights (eg Seattle to Vancouver) when the posted duration might be twice the length of the actual flight!

Over the years, I've watched the travel times on certain routes increase steadily. You may also notice that morning flights have shorter travel times than afternoon flights on the same routes. (For example, search AA.com for flights between ORD and LGA. The first flight of the morning is scheduled at 1 hour, 58 minutes. As the morning progresses, flight times increase to 2h 5m, with a peak afternoon time of 2h 12m.)

At O'Hare, which is my local airport, it can take 20 minutes to taxi between certain gates and certain runways.

Jet stream is also a major determiner in time for TPAC and TATL flights. This is why going east from NA is always quicker.

You also have to compare like-for-like.

LHR flight times include the long queue to get onto the actual runway and the almost guaranteed need to hold on the return. At LGW, it's much quicker to get onto the runway and holds are less likely.

Yes, but in the OP's example, the block time on the LGW flight is 1hr 05m longer than the LHR flight

AC and BA block YYC-LHR at 8:35. TS does it in 8:45. Westbound BA is 8:45, AC is 8:50 and TS is 9:25 (all times based on 15 OCT departure).

The 35-40 minute longer block time westbound is likely attributable to the departure time (TS in the morning when LGW is busier so longer taxi times) and the fact that the TS A330/B767 flies slightly slower than the AC & BA 787s/777s on average. The impact of this is magnified westbound with headwinds.

Actual flight times westbound on TS in the past week ranged from 8:30 to 9:23. On AC the range was 8:05-8:49 and BA was 7:58-8:57.

Some airlines will also have more padding on the return flight to a home base than the outbound, particularly if the turnaround is relatively short.

It depends on the routing. Flights tend not to go in a straight (well, accounting for the curvature of the Earth) line, but point to point..and flight paths can be more of a zig-zag pattern and that can add time.

Other considerations are altitude and direction. Air is denser lower down, and that can mean slower speeds.

Direction of travel has an impact as well, although this doesn't apply to the flights you mentioned. In the northern hemisphere, westbound flights take longer because of the prevailing winds which go west to east. In the southern hemisphere the reverse happens, because winds tend to go east to west. A flight from LAX to YYZ may be 4.5 hours, but YYZ-LAX is 5.5 on average.

Other airlines may vary because of assigned fuel burn. They may slow down to maintain lower consumption so they don't have to refuel as much at the destination depending on where the aircraft is going next and what deals they got on fuel.

Not quite right. Near the equator in both hemispheres prevailing winds are easterly. In mid to high latitudes in both hemispheres prevailing winds are westerly.

Thank you so much for your informative replies - I have learned a lot and it all makes perfect sense now. many thanks

That's actually the opposite of what the schedule is. The TS flight from LGW is the one with the longer schedule time. More likely the difference is due to aircraft type, as the AC and BA flights from LHR operate with a Boeing 787-8 and the TS flights from LGW use an Airbus 330-200. The 787 has a standard cruise speed of mach .85 (487 knots) while the A330 has a slower standard cruise speed of mach .82 (470 knots). This speed difference would account for at least some of the difference in flight times and climb and descent speed could account for additional differences. It's also possible that TS flies even a little slower for greater fuel efficiency.