Route Penalty

[Kinder]

Hi,

I'm having a "aircraft too small" warning for one of my flight (~2300NM) that I try to change (A318/A319 to A220-100/300ER).

How come I'm having a warning for the A220 and no one for the 318/319? They are basically the same.

I suppose the base characteristics of a family is based on the biggest airplane, in this case the A321?

[Kinder]

Ok now I'm confused...

The previous route was 2340NM and I got a warning, then I tried routes with 2157, 2357, 2383 and 2451NM and got no warning...

All airports are infrastructure and traffic level >5

Is it passenger demand and distance based? The 2340NM one was the only one at ~350pax, the other ones were below 300pax

[sanabas]

I suppose the base characteristics of a family is based on the biggest airplane, in this case the A321?

I think it's average across the fleet.

Is it passenger demand and distance based? The 2340NM one was the only one at ~350pax, the other ones were below 300pax

Yep, combination of both.

[Kinder]

I think it's average across the fleet.

Yep, combination of both.

Then there must be a problem, another route:

2383NM, demand ~250pax/260pax, warning
2451NM, demand ~250pax/260pax (same as above), no warning...

Both route have the same payload limitation.

At least I could understand if it was an Embraer E2 (medium aircraft), but the A220 is a large aircraft, like the A318/319. Perhaps it's a typo, because the E2s/A220 are the same size as the A320 family

[Tha_Ape]

Range. There's a threshold at 2400nm.

In a previous GW, I had a 2380n route @1200 pax, fine with the A321, and a 2420nm route @400 pax, asked for something larger than an A321.

Yes, it leads to stupid things like my example above, but so far it's the system we're working with. There is to be a limit, and a limit always creates absurdities.

[sanabas]

<2400 =international flight, >2400 = LH flight.

[Kinder]

Range. There's a threshold at 2400nm.

2383NM, demand ~250pax/260pax, warning
2451NM, demand ~250pax/260pax (same as above), no warning...

It makes no sense!

In a previous GW, I had a 2380n route @1200 pax, fine with the A321, and a 2420nm route @400 pax, asked for something larger than an A321.

Yes, it leads to stupid things like my example above, but so far it's the system we're working with. There is to be a limit, and a limit always creates absurdities.

I think the families should be split, less than 150pax and more than 150pax, or base the categories on the MTOW and apply the limitation to aircraft size/MTOW. Perhaps it's done like this already, I don't know.

BTW, the stats of the A220-100 are wrong, it can go up to 135 seats (and up to 3400NM)

[Kinder]

<2400 =international flight, >2400 = LH flight.

Did you check the previous post?

2383NM, demand ~250pax/260pax, warning
2451NM, demand ~250pax/260pax (same as above), no warning...

[Tha_Ape]

Did you check the previous post?

I don't see where Sanabas is wrong. And yes, it doesn't make sense, but that's the way it is. Can complain, but until a change, you have no choice but to play by the system.

I think the families should be split, less than 150pax and more than 150pax, or base the categories on the MTOW and apply the limitation to aircraft size/MTOW. Perhaps it's done like this already, I don't know.

Families aren't split. It's the average of the family that counts. Thus, a warning doesn't necessarily means you have the penalty: penalty might be for the smaller A318 but not for the A319 and above, however the planning tool has no possibility to know what exact sub-model you'll use.

And 150 is not a measurement. There is also "too small" for, say, a 1100nm route with 500 demand that you would fly with a CRJ 100. Or a 600nm route, 200 demand flown with a Be99 with a tech stop.

[sanabas]

Did you check the previous post?

Yes. One is an international short haul flight, one is a long haul flight. That's why you happen to have counterintuitive results in this case. Too small warnings are still based on a combination of route size, route type, route distance and the average seating capacity of a fleet group. And also what year it is. An a320 on the route in 1990 might be fine. An a320 on the same route in 2030 might be flagged as too small.

There are 3 categories of flight, domestic, intl SH, intl LH. You can see the three have different ratios for the default F & C seat price to the default Y seat price. It's also relevant for how demand is calculated between airports, if you look somewhere that has SH demand but no LH demand, you'll see a distinct cutoff in route size as you go past 2400nm. HND after Narita opens is a good example.

Further to the examples in the previous post, I've also seen too small warning trying to put a 20 seater on a very short, very large route like Taipei-Hong kong, where a 120 seat like a 734 is ok. So trying to pick only <150 and >150 wouldn't make sense.

What's there does make sense, even if it sometimes throws up counterintuitive results.

[Kinder]

Yes. One is an international short haul flight, one is a long haul flight. That's why you happen to have counterintuitive results in this case. Too small warnings are still based on a combination of route size, route type, route distance and the average seating capacity of a fleet group. And also what year it is. An a320 on the route in 1990 might be fine. An a320 on the same route in 2030 might be flagged as too small.

That's what I find disturbing, the LH flight (>2400) doesn't have a warning, while the international SH ones do (<2400).

Ok some more informations :

Year : 2016

SKBO - SBGR, 2340 NM, 350/350pax, warning with A220, no warning with a320 family (currently using A318/A319s)
SKBO - SBGL, 2451 NM, 250/260pax, no warning with A220, no warning with A320 family (also using A318/A319s)
SKBO - SBGR, 2383 NM, 250/260pax, warning with A220, no warning with a320 family (also using A318/A319s)

What I'm asking is why I can fly them with the 320 family and why I can't with the A220 family, they are the same technically.

[sanabas]

What I'm asking is why I can fly them with the 320 family and why I can't with the A220 family, they are the same technically.

The a220 family has a smaller average size than the a320 family. Simple as that. The planner has no idea if you're going to put an a318 or an a321 there, so warnings are based on the average size of each fleet.

Even though you've said both routes are 250/260, it might be the case that one is actually 240 and one is actually 270, so you're only getting warned on the slightly longer route.

And despite getting a warning, you can still fly them. It's only going to be just over the threshold to generate a warning, so you're only going to be penalised very slightly. And only then if there are competitors flying bigger planes on the route.

Also, just did some quick experimenting. I think the border is actually 2400NM for flying to a different continent, 3400 for flying to same continent. So all 3 of the routes are intl SH, not LH.

[Kinder]

The a220 family has a smaller average size than the a320 family. Simple as that. The planner has no idea if you're going to put an a318 or an a321 there, so warnings are based on the average size of each fleet.

They are almost the same (MTOW, length, wingspan), "only" differences are cabin width (3.28m vs 3.70m), seating (3x2 vs 3x3) and fuel capacity.
The Embraer E2 really are medium aircrafts and I must have a warning if I try to use them for these routes, but not the A220, they shouldn't have warnings (well, it's only a warning...)

Even though you've said both routes are 250/260, it might be the case that one is actually 240 and one is actually 270, so you're only getting warned on the slightly longer route.

It's actually 240-250 and 240-260 roundtrip, it never goes above 260 (I refreshed the page a LOT, Sami will kill me if he knows )

And despite getting a warning, you can still fly them. It's only going to be just over the threshold to generate a warning, so you're only going to be penalised very slightly. And only then if there are competitors flying bigger planes on the route.

I'll check if I'm really penalised later

Also, just did some quick experimenting. I think the border is actually 2400NM for flying to a different continent, 3400 for flying to same continent. So all 3 of the routes are intl SH, not LH.

That's why I don't understand the warning, all are intl SH, A320 family and 737s don't have warnings.

Thanks for the replies!

[Tha_Ape]

A220 average seating for all models
(-100 + -100LR + -300 + -300LR, divided by 4)
is way below the average of the A32x family
(A318 + A319-100 + A319neo + A320-100 + A320-200 + A320neo + A321-100 + A321-200 + A321neo + A321neoLR + A321neoXLR, divided by 11)

A220 being large doesn't matter, its average is around 115 pax. While A32x family is more likely around 150-160, if not 170.

[LemonButt]

I believe the warning is based on the smallest variant in a fleet.  I frequently get the message for CRJs which on the low end are 50 seaters and the high end 100 seaters.  They larger ones are designed for routes 1000+ nm but the warning pops up because it assumes you might be flying a 50 seater 1000+ nm.  Note that the warning doesn't say definitively that it is too small...it says *may* be too small.  If you aren't flying the smallest variant, you should be fine in most cases.

[Tha_Ape]

@LB

I believe the warning is based on the smallest variant in a fleet.

Nope. Been reassessed quite a few times in the last 2 years. There's even a changelog about it (fix), as at some point combis were wrongly counting towards this average, and dragging it down.