Airlines' 'padding' of schedules

[Melburnian1]

I asked how you would fix your perceived problem....

Pleas read the fourth and (one line) fifth paragraph.

By the way, it's not some 'perceived problem': it's fact that's occurring every day as the BBC article states and those quoted concur with.

 

[odysseus]

I actually find it a good analogy to trains, at least in the local context.

Cityrail added substantial padding to its times as well, roughly around a decade ago, such that many trains now dawdle along just to be on time. The issue was they weren't meeting their 90% on time target (which already had 5min contingency, and was only at one station) so just made their target even easier to meet.

As far as comparison though, almost all train services do not have dedicated lines, and moreover have to share with varying speed services. They don't have the choice of as many paths as airlines do. Moreover, they also have to suffer unexpected interruptions, whether it be weather, "police action" or a whole host of other things down to even waiting for cars to cross in some places!

As for the aviation situation though, it requires individual detailed analysis for an assessment. Certainly one point that can be addressed is that where a different craft takes a different flight, the timing should vary based on that timetabled entry. If it is substituted well that is where variations may occur. However, the timing shouldn't just be the same for every different craft. Even in rail they do offer different timing for different types of equipment...

 

[Forg]

I didn't understand the negative the article was saying was there, it kept saying "this is happening" but didn't convince me that I cared (or that it was bad). It even mentioned environmental negatives, but didn't elaborate; maybe I TLDR'd before it said what they were?

 

[sjk]

I struggled to read beyond this, which makes no sense to me whatsoever. Hard to view the article as anything like “scholarly “ research:

“On average, over 30% of all flights arrive more than 15 minutes late every day despite padding,” says Captain Michael Baiada, president of aviation consultancy ATH Group citing the US Department of Transportation’s Air Travel Consumer Report.

What percentage would you need it to be to conclude that padding has been eliminated?

 

[ayebee]

I like the padding in the schedule. It allows some contingency and helps you when planning connecting flights.

Agree. I think it is also about managing expectations, and in some places avoiding handing out compensation when multiple variables disrupt the plan.

 

[Melburnian1]

... It even mentioned environmental negatives, but didn't elaborate; maybe I TLDR'd before it said what they were?

Its point was summarised by Captain Michael Baiada of an aviation consultancy who said' “Padding drives higher costs in fuel burn, noise and CO2..."

 

[Melburnian1]

...in some places avoiding handing out compensation when multiple variables disrupt the plan.

That point is made in the article about EU261. We lack any such compensation measure here.

Importantly, the article has a named source who suggests that 80 per cent of problems are within an airline's ability to control. MEL_Traveller has been 'big' on this in other threads. AFFer sjk may wish to note that point.

 

[Melburnian1]

...I think it is also about managing expectations...

"managing expectations" is a synonym for "mediocrity", of which we see far too much in Australia.

 

[dajop]

Its point was summarised by Captain Michael Baiada of an aviation consultancy who said' “Padding drives higher costs in fuel burn, noise and CO2..."

Trying to understand the logic here. I thought the argument was that padding was adding unnecessary time to schedule (in case of delays) to make statistics look good - but essentially the gate to gate time remains the same as it would without padding. So how does that increase fuel burn, noise and CO2? The logic has me befuddled.

I thought it was increased traffic and congestion drives higher gate to gate times, which in turn means b higher fuel burn, etc, whilst padding decreases capital utilisation, thus increasing capital costs.

 

[Melburnian1]

dajop, the Captain's point seems to be that schedule padding encourages airlines to be even more lax/slack, and takes away an urgent need to manage the fligfht in its mid stages, which in turn would drive operational efficiency and bring lowered costs for airlines.

It's the airline equivalent of what we may have been told as children by anxious or strict parents who lectured us saying 'I won't give you an inch (of latitude) because you'll take a mile.'

So both he and you are right: just two ways to get to a similar answer.

 

[p--and--t]

Just to chime on a different angle in on the increasingly animated cut and thrust of this subject.

I would much prefer an airline "pad" their timings to be as predictably consistent as possible so I have confidence I will be able to meet my connecting flight on a tight transfer.

If the flight arrives "early" - a bonus some more time to use the lounge / have a shower / have a second drink / trust my luggage gets transferred.

Cutting the padding and increasing the risk the number of times the incoming flight will arrive late, puts the typical short changeovers for passengers at airports like Hong Kong (50m-70m between landing and takeoff) at very significant risk.

 

[Melburnian1]

Just to chime on a different angle in on the increasingly animated cut and thrust of this subject.

I would much prefer an airline "pad" their timings to be as predictably consistent as possible so I have confidence I will be able to meet my connecting flight on a tight transfer.

If the flight arrives "early" - a bonus some more time to use the lounge / have a shower / have a second drink / trust my luggage gets transferred.

Cutting the padding and increasing the risk the number of times the incoming flight will arrive late, puts the typical short changeovers for passengers at airports like Hong Kong (50m-70m between landing and takeoff) at very significant risk.

Can see why you say that, but you're already cutting it fine if you've a 50 minute connection. If it's to make the final flight of the day on a route with relatively infrequent flights, fair enough, but if on a heavily trafficked route, to me it's foolhardy, maybe not so much for you as the passenger, but expecting your checked luggage to make it every time, and better to have a later flight as the connection on your PNR.

Not disputing HKG is efficient, but I've had the occasional risky connection elsewhere such as at KUL and found once to my chagrin that not all luggage was transferred in time.

And many connections at HKG require more than 50 minutes:

CXAgents USA - Support - Minimum connecting times (MCT)

Not everyone is transferring onto another flight. OD traffic may also be important, and unarguably as the article suggests, these passengers suffer with current practices.

 

[dajop]

dajop, the Captain's point seems to be that schedule padding encourages airlines to be even more lax/slack, and takes away an urgent need to manage the fligfht in its mid stages, which in turn would drive operational efficiency and bring lowered costs for airlines.

I was under the impression, and maybe this is something jb747 can answer, that flights are managed somewhat for fuel efficiency, that a faster flight could actually burn more fuel than a slightly slower flight. Not sure how accurate this is.

With the intense pressure on costs, with everything gone over with a fine toothcomb, I refuse to believe that when airlines are cutting catering, trying to convert to all electronic boarding passes to reduce the cost of paper etc, they are not carefully looking at how fuel is utilised and routes are optimised to minimise overall cost of operating that route.

 

[p--and--t]

Can see why you say that, but you're already cutting it fine if you've a 50 minute connection. If it's to make the final flight of the day on a route with relatively infrequent flights, fair enough, but if on a heavily trafficked route, to me it's foolhardy, maybe not so much for you as the passenger, but expecting your checked luggage to make it every time, and better to have a later flight as the connection on your PNR.

Not disputing HKG is efficient, but I've had the occasional risky connection elsewhere such as at KUL and found once to my chagrin that not all luggage was transferred in time.

And many connections at HKG require more than 50 minutes:

CXAgents USA - Support - Minimum connecting times (MCT)

Not everyone is transferring onto another flight. OD traffic may also be important, and unarguably as the article suggests, these passengers suffer with current practices.

In the last few months, on booking the last three flights thru Hong Kong, I only selected Mel departure and my goal arrival point. On each occasion I was offered a short connection via Hong Kong by both Cathay (50min) and Qatar (70min) changeover (to/from Danang and Doha)

It is the airlines offering me the connection as standard practice, not me "choosing" a dicey connection.

They must have confidence based on historical records (and presumably padding) that they can achieve the connection routinely regardless of Air Traffic Control idiosyncrasies & wind patterns.

(BTW: I made all three connecting flights)

 

[Melburnian1]

...With the intense pressure on costs, with everything gone over with a fine toothcomb, I refuse to believe that when airlines are cutting catering, trying to convert to all electronic boarding passes to reduce the cost of paper etc, they are not carefully looking at how fuel is utilised and routes are optimised to minimise overall cost of operating that route.

They may well be, and so might Airservices Australia (as latter's publicity indicates) plus similar air traffic entities overseas. But since airlines still pad schedules, it's not optimal efficiency that they strive for.

There can't be too much 'intense pressure on costs' if entities like EY/VA and many others still pay very high salaries or overall remuneration to numerous executives yet airlines often make multibillion or mutli tens of million dollar losses, or don't achieve what would be considered an acceptable return on capital employed.

 

[ayebee]

"managing expectations" is a synonym for "mediocrity", of which we see far too much in Australia.

I understand your feeling, and no doubt it can be done in a cynical way, but I disagree it is a synonym.
I worked on both customer and supplier sides of sizable technology projects in Oz plus US, Europe & Asia and it was standard commercial practice to build in contingency appropriate to the price / cost, which I view as realistic "expectation management" and understanding the consequences.

 

[jb747]

I was under the impression, and maybe this is something jb747 can answer, that flights are managed somewhat for fuel efficiency, that a faster flight could actually burn more fuel than a slightly slower flight. Not sure how accurate this is.

With the intense pressure on costs, with everything gone over with a fine toothcomb, I refuse to believe that when airlines are cutting catering, trying to convert to all electronic boarding passes to reduce the cost of paper etc, they are not carefully looking at how fuel is utilised and routes are optimised to minimise overall cost of operating that route.

Fuel is very finely managed. If the airlines actually got their way (and weren’t interfered with by those pesky pilots), all flights would have the absolute minimum legal amount...measured to the kg. I was never all that big on having to declare an emergency if we happened to go around, but that’s the level of tightness (or whatever word you consider more appropriate) the fuel planning fairies have descended to.

Aircraft speeds are not all that variable. The difference between the maximum speed available, and the minimum may only be 15 or 20 knots. When we say we’re going to go faster, we aren’t talking about much....5-10 knots. Over 10 hours that will make a difference, but it’s rarely worthwhile on shorter sectors. Conversely, the fuel cost is almost always excessive. A 2% increase in speed might lead to a 5% increase in overall burn. On long sectors, couple with minimum fuel planning, there simply won’t be enough fuel available to make any difference.

 

[cambriamarsh]

I understand your feeling, and no doubt it can be done in a cynical way, but I disagree it is a synonym.
I worked on both customer and supplier sides of sizable technology projects in Oz plus US, Europe & Asia and it was standard commercial practice to build in contingency appropriate to the price / cost, which I view as realistic "expectation management" and understanding the consequences.

Interesting thread. FWIW I prefer some padding so I can rely on the arrival times, both for connection management and also for setting up meetings etc.

There are a LOT of variables that can affect flight times and my preference is that the timings result in 85% or better on time or earlier arrival. For me it just works better that way but of course YMMV.

 

[Melburnian1]

At post #19, jb747 said "...A 332 is much faster than a 737....so if there's a mix, which aircraft timing would you use. "

While he may be discussing something a little different, at post #37, he referred to how over shorter sectors the difference between the maximum and minimum speeds isn't that much and that aircraft speeds are not all that variable.

So for a 3.5 or 4 hour sector like MEL-PER or return, how many minutes faster will an A332 typically be than a B738 (assuming identical taxiing times, and flying conditions)?

 

[Quickstatus]

I think airline schedules are padded but necessarily so. It would be impossible to arrive on time to an arrival slot and gate, if some contingencies are not built in to a timetable to account for the multiple variables that beset an aircraft operation.

Some of the variables have been discussed above.
The departure and arrival routing to a degree is also another variable.
For example SYD has the 16/34 runway (the main north south runway)
Depending on the runway used aircraft could either come straight in or have to circle around at low speed from the other side which adds flight time. How can this be accounted for so notwithstanding any holding patterns during busy periods.

Some aircraft have flight computers which targets the flight according to selected outcomes. Some of those outcomes might be minimal flght duration or lowest cost. Minimising flight duration may be possible up to a point but is limited by fuel. Lowest cost target is (simplistically) flying at the most fuel efficient speed and altitude, but ATC might prevent the most efficient altitude. So to a point pilots can save a bit of time here or there, but I understand it is not much. And even if departure or arrival is early, other factors as discussed will throw it all out the window.