What reasons, other than operational weight and balance would an airline hold seats away from sale for?

I have friends flying United Express RIW-DEN next month (Dec 17th) who were told that they're afternoon departure was canceled and to pick an alternate flight. They tried for the morning of the same day, but were told that this was unavailable even though only 35 out of the 50 seats on the morning CRJ-200 were booked and thus had to pick the next day for their flight. What would make United hold 15 seats away from sale a month out?

It seems that Riverton 8,200 feet airport should be able to handle a full CRJ load on the short flight to Denver in the winter as I know it definitely can in the summer, so I hypothesized that for some reason United was trying to hold 15 seats in order to sell them at a higher price later.

Or could it be something like a 15-passenger group sale that United expects to make?
Or United hedging its bets against a regional pilot shortage and having to cancel/consolidate further?
Or are the 15 seats being held for people who were bumped from other cancelled flights on other surrounding days to pick from, and United doesn't want people bumped from December 17th's cancelled afternoon flight to take up all of December 17th's morning flight when it also needs to accommodate bumped afternoon passengers from Dec 16th, 18th, and 19th?

Currently no seats shown for sale on Dec 17th or 18th


It was just interesting because I couldn't give any good answers to my friends as to why they couldn't pick from open inventory.

Thanks for any thoughts.

Well, with winter pax weights, unless you have children, you physically don't have ability to take 50 adults on the plane, without an alternate (MZFW limitations are the usual issue). Throw in the need for an alternate, and United may decide they don't want to sell more than 35 seats.

You can completely discount holding seats for higher fares later- no need to do that- simply zero out all sub-classes and make full Y available as the only fare.

My guess is they don't buy fuel at RIW, meaning they have to restrict for CG.

DiamondFlyer wrote:

Well, with winter pax weights, unless you have children, you physically don't have ability to take 50 adults on the plane, without an alternate (MZFW limitations are the usual issue). Throw in the need for an alternate, and United may decide they don't want to sell more than 35 seats.

Then they wouldn't sell full airplanes out of DEN either.

N1120A wrote:

My guess is they don't buy fuel at RIW, meaning they have to restrict for CG.

DiamondFlyer wrote:

Well, with winter pax weights, unless you have children, you physically don't have ability to take 50 adults on the plane, without an alternate (MZFW limitations are the usual issue). Throw in the need for an alternate, and United may decide they don't want to sell more than 35 seats.

Then they wouldn't sell full airplanes out of DEN either.

Fuel makes very little difference in the CG of a 200. I just don't see that holding back 15 seats.

Maybe it’s this…..

https://news.google.com/articles/CBMiSm ... id=US%3Aen

https://news.yahoo.com/heavier-american ... 00587.html

50 seat planes were already bumping up against weight limits before the weight increase last year. So 50 seat jets are running into the same problem that 30seat turboprops ran into when the weight went up from 170 to 190 in the early 2000s They couldn’t carry the full 30 pax anymore

Plus RIW to DEN is such a short flight you’re probably running up against a max landing weight issue rather than a max takeoff weight issue. If the flight flew farther like to Chicago or LA instead then they probably don’t have to block the seats because landing weight is no longer an issue.

Could very likely be 15 pax who have purchased tickets but don’t want to pay a dime for United’s “premium seats”

Those seats will show open on the on line seat map because they have not been assigned but the flight may be sold out.

atcdan wrote:

Could very likely be 15 pax who have purchased tickets but don’t want to pay a dime for United’s “premium seats”

Those seats will show open on the on line seat map because they have not been assigned but the flight may be sold out.

Guess I should have clarified it earlier, but the "15 open", comes from another friend who checked United's Passrider E-Res and saw "15" in the "Held" category. It's just still confusing because I can't find any very plausible reason that fits all the facts.

8500ft length at 5500ft elevation … no problem on a good day but will have significant weight restrictions with winter weather conditions. Could be a contributing factor.

It could also be a cargo contract. They may have a standing order for cargo that would weight limit the plane. It usually only happens on mainline flights but it can happen on a regional also.

There could be 15 Positive-Space non-revs going so they pre-blocked the seats. I know, not very likely.

Okcflyer wrote:

8500ft length at 5500ft elevation … no problem on a good day but will have significant weight restrictions with winter weather conditions. Could be a contributing factor.

What would be limiting about winter weather? Too good performance of engines and wings?

Nicoeddf wrote:

Okcflyer wrote:

8500ft length at 5500ft elevation … no problem on a good day but will have significant weight restrictions with winter weather conditions. Could be a contributing factor.

What would be limiting about winter weather? Too good performance of engines and wings?

Runway friction coefficient is a thing, and snow/ice tends to change it.

A CRJ-200 has an average empty weight of 31300 lbs - each aircraft is different

Max Takeoff Weight is 53,000lbs, max landing weight is 44,000lbs, max zero fuel weight is 47,000lbs

So we are going on a flight from RIW to DEN a distance of 274nm along a routing of KRIW TOFUU.FLATI3 KDEN enroute fuel burn is 3,500lbs flight time of 0:45.

Fuel load for this flight will be 8000lbs... 3,500 enroute fuel burn + 3,500lb 45 minute reserve + 500 taxi and + 500 dispatcher add for unforseen circumstances.

So before loading pax, the aircraft weighs:

31,300 + 8,000lbs = 39,300lbs well below max takeoff weight...

load 50 pax = 50 pax x 205lbs (winter weight) = 10,250lbs
lets say these 50 pax have 40 bags x 30lbs = 1,200lbs

39,300lbs + 10,250 + 1,200 = 50,750 lbs = still well below the max takeoff weight of 53,000 lbs....

but because the enroute burn is 3,500lbs we are limited by the maximum landing weight of 44,000lbs + enroute fuel burn of 3,500lbs

so our actual maximum takeoff weight for this flight is 47,500lbs - well below the structural maximum takeoff weight of 53,000lbs.

if we took off at 50,750lbs with all 50 passengers, we will arrive at denver weighing 47,250lbs - which is 3,250lbs overweight to land at Denver. We would need to hold over Denver to burn off those 3,250lbs... which will take 54 mins of holding to burn off 3,250lbs

So to get the aircraft from 50,750lbs to 47,500lbs we have to remove 3,250lbs of payload

either remove all of the bags and some of the passengers or some combination thereof.

3,250lbs = 15.8 passengers...

so we have to remove 15.8 passengers to get the weight of the aircraft below maximum takeoff weight for this RIW to DEN flight...

so there is your 15 seats.

Winter weather would mean an alternate would need to be added which requires more fuel, but we are still limited to the MLW + enroute burn and so to carry the extra fuel for an alternate we would need to remove even more passengers to accommdoate the extra fuel.

Woodreau wrote:

A CRJ-200 has an average empty weight of 31300 lbs - each aircraft is different

Max Takeoff Weight is 53,000lbs, max landing weight is 44,000lbs, max zero fuel weight is 47,000lbs

So we are going on a flight from RIW to DEN a distance of 274nm along a routing of KRIW TOFUU.FLATI3 KDEN enroute fuel burn is 3,500lbs flight time of 0:45.

Fuel load for this flight will be 8000lbs... 3,500 enroute fuel burn + 3,500lb 45 minute reserve + 500 taxi and + 500 dispatcher add for unforseen circumstances.

So before loading pax, the aircraft weighs:

31,300 + 8,000lbs = 39,300lbs well below max takeoff weight...

load 50 pax = 50 pax x 205lbs (winter weight) = 10,250lbs
lets say these 50 pax have 40 bags x 30lbs = 1,200lbs

39,300lbs + 10,250 + 1,200 = 50,750 lbs = still well below the max takeoff weight of 53,000 lbs....

but because the enroute burn is 3,500lbs we are limited by the maximum landing weight of 44,000lbs + enroute fuel burn of 3,500lbs

so our actual maximum takeoff weight for this flight is 47,500lbs - well below the structural maximum takeoff weight of 53,000lbs.

if we took off at 50,750lbs with all 50 passengers, we will arrive at denver weighing 47,250lbs - which is 3,250lbs overweight to land at Denver. We would need to hold over Denver to burn off those 3,250lbs... which will take 54 mins of holding to burn off 3,250lbs

So to get the aircraft from 50,750lbs to 47,500lbs we have to remove 3,250lbs of payload

either remove all of the bags and some of the passengers or some combination thereof.

3,250lbs = 15.8 passengers...

so we have to remove 15.8 passengers to get the weight of the aircraft below maximum takeoff weight for this RIW to DEN flight...

so there is your 15 seats.

Winter weather would mean an alternate would need to be added which requires more fuel, but we are still limited to the MLW + enroute burn and so to carry the extra fuel for an alternate we would need to remove even more passengers to accommdoate the extra fuel.

So with your math, landing at a regular destination with regular reserves would mean 31300 empty + 3500 reserve +500 dispatcher extra + 10,250 pax + 1,200 bags = 46750, and CRJ-200 never should operate with full winter pax load in winter, even if there are no bags and dispatch fuel extra?

Starlionblue wrote:

Nicoeddf wrote:

Okcflyer wrote:

8500ft length at 5500ft elevation … no problem on a good day but will have significant weight restrictions with winter weather conditions. Could be a contributing factor.

What would be limiting about winter weather? Too good performance of engines and wings?

Runway friction coefficient is a thing, and snow/ice tends to change it.

Of course you are right. Somehow my brain stopped after thinking about half the issue only.

Woodreau wrote:

A CRJ-200 has an average empty weight of 31300 lbs - each aircraft is different

Max Takeoff Weight is 53,000lbs, max landing weight is 44,000lbs, max zero fuel weight is 47,000lbs

So we are going on a flight from RIW to DEN a distance of 274nm along a routing of KRIW TOFUU.FLATI3 KDEN enroute fuel burn is 3,500lbs flight time of 0:45.

Fuel load for this flight will be 8000lbs... 3,500 enroute fuel burn + 3,500lb 45 minute reserve + 500 taxi and + 500 dispatcher add for unforseen circumstances.

So before loading pax, the aircraft weighs:

31,300 + 8,000lbs = 39,300lbs well below max takeoff weight...

load 50 pax = 50 pax x 205lbs (winter weight) = 10,250lbs
lets say these 50 pax have 40 bags x 30lbs = 1,200lbs

39,300lbs + 10,250 + 1,200 = 50,750 lbs = still well below the max takeoff weight of 53,000 lbs....

but because the enroute burn is 3,500lbs we are limited by the maximum landing weight of 44,000lbs + enroute fuel burn of 3,500lbs

so our actual maximum takeoff weight for this flight is 47,500lbs - well below the structural maximum takeoff weight of 53,000lbs.

if we took off at 50,750lbs with all 50 passengers, we will arrive at denver weighing 47,250lbs - which is 3,250lbs overweight to land at Denver. We would need to hold over Denver to burn off those 3,250lbs... which will take 54 mins of holding to burn off 3,250lbs

So to get the aircraft from 50,750lbs to 47,500lbs we have to remove 3,250lbs of payload

either remove all of the bags and some of the passengers or some combination thereof.

3,250lbs = 15.8 passengers...

so we have to remove 15.8 passengers to get the weight of the aircraft below maximum takeoff weight for this RIW to DEN flight...

so there is your 15 seats.

Winter weather would mean an alternate would need to be added which requires more fuel, but we are still limited to the MLW + enroute burn and so to carry the extra fuel for an alternate we would need to remove even more passengers to accommdoate the extra fuel.

Your numbers are wrong. MZFW is 44000, MLW is 47000. Additionally I've never seen a 200 with at BOW of 31300, they're usually closer to 32000, if not over.

Crap. I knew I mixed up the numbers somewhere. But it’s been about 20 years.

Woodreau wrote:

Crap. I knew I mixed up the numbers somewhere. But it’s been about 20 years.

For what it's worth, all the other math was good. 50 pax + 1200 lbs of cargo would never be within CG of a 200, unless you had a bunch of permanently installed aft ballast (like Air Wisconsin).

Coming from a ski resort? It's not just the seats but cargo weight with all the stuff skiers Bring with them. What the airplane CAN Carry? might well be different from Summer to Winter.. Just as it's claimed that Americans are getting "Fatter" and instead of the std. 170 lb avg. it's looking like 125KG. might be closer to the average.

Could this be related to Skywest creating a part 135 operation?

https://thepointsguy.com/news/skywest-c ... -seat-crj/