Are airliners headed into uncharted territory?

Dav8or

Dav8or

Final Approach
Joined
Jan 6, 2007
Messages
5,174
Location
Discovery Bay, CA
Display Name
Display name:
Dave
Things have changed in the airline industry in the last 10-15 years. I just got back from Mexico tonight on a commercial airliner and it made me think, I can't remember the last time I flew on an airliner that wasn't packed all the way full in every seat, or very near it. They seem to have figured out how to pack every plane to max gross, every time. This is quite in contrast to the 50-75% full planes I used to ride on in the past.

This made me think about aircraft fatigue. I know that aircraft engineers design planes so that they can fly at max gross with a good safety margin. I know the plane and the pilots are up to the task of flying heavy on every flight, but it seems to me that that our knowledge of service limits on airframes and aircraft parts are based in part by actual time in service, not just calculations. If a lot of those calculations and declared life limits are based on data observed back when planes were running maybe an average of 75% capacity, what does that mean moving forward?

Are we in uncharted territory? Will we see more structural and mechanical failures we didn't anticipate? I used to run a fleet of trucks and I can tell you that if you run them at max weight everyday, they will fail faster and not last as long as trucks lightly loaded. Just the way it is.
 
Why make the max gross weight of an aircraft what it is, if it isn't safe to operate that way?

I've never understood the massive fear some pilots have of operating at max gross. Know the performance data, do a weight and balance, know the weather and she still flies.
 
MichiPilot said:
Why make the max gross weight of an aircraft what it is, if it isn't safe to operate that way?

I've never understood the massive fear some pilots have of operating at max gross. Know the performance data, do a weight and balance, know the weather and she still flies.
Click to expand...
You missed his entire point. He expressed no fear.
 
You seem to think that filling all the seats somehow is a load not expected by the designers. This one isn't as far fetched as some of the other life limit things that have been shown to be problems like high number of cycles compared to time in service, etc...

While many of the mainstream carriers haven't had load factors approaching 100% in the past, a lot of the smaller carriers and certainly many of the charter operations have, so it's not "uncharted territory" either.
 
flyingron said:
You seem to think that filling all the seats somehow is a load not expected by the designers. This one isn't as far fetched as some of the other life limit things that have been shown to be problems like high number of cycles compared to time in service, etc...

While many of the mainstream carriers haven't had load factors approaching 100% in the past, a lot of the smaller carriers and certainly many of the charter operations have, so it's not "uncharted territory" either.
Click to expand...

The point is not one of expectations themselves, but if the basis data that the expectations were founded on is correct.

The reality is, it doesn't matter. Every minute of every day we enter new territory. The engineering data is formed on enough various data points that design conclusions are not greatly affected by actual life load vs design life load.
 
Perhaps it's safer. When are you most likely to over-stress an airframe in turbulence? Light or heavy? One could argue light since Va drops as you go lighter but most don't adjust their speeds accordingly.

I think the fleet will be fine. Airlines making money can afford proper maintenance.
 
LDJones said:
Perhaps it's safer. When are you most likely to over-stress an airframe in turbulence? Light or heavy? One could argue light since Va drops as you go lighter but most don't adjust their speeds accordingly.

I think the fleet will be fine. Airlines making money can afford proper maintenance.
Click to expand...


:confused: I'm not real sure that the first statement is supported by the second as applied to the real world. Airlines haven't been particularly profitable since deregulation and are often caught cutting corners on maintenance.
 
Henning said:
:confused: I'm not real sure that the first statement is supported by the second as applied to the real world. Airlines haven't been particularly profitable since deregulation and are often caught cutting corners on maintenance.
Click to expand...

They're making record profits at the moment. Affording and performing are two different things, but you definitely don't get the latter without the former.
 
Dav8or said:
Are we in uncharted territory? Will we see more structural and mechanical failures we didn't anticipate? I used to run a fleet of trucks and I can tell you that if you run them at max weight everyday, they will fail faster and not last as long as trucks lightly loaded. Just the way it is.
Click to expand...

Using this same logic all Cessna 150/152s would be located at the bottom of smoking holes. They are very frequently flown over gross...

-Skip
 
Flying aircraft at gross is nothing new in the working airplane world.
 
But it's not even uncharted territory as far as the airframes are concerned. Perhaps it's uncharted for certain of the US airlines, but I can tell you there are charter and foreign operators who fly with every seat full every flight and have done so for years.
 
airlines have always operated at gross, full seats or empty seats. They have cargo sitting there ready to go and if there is extra weight available it gets loaded
 
Keep in mind that airliners are sold to 2nd and 3rd tier operators (in 3rd world countries) well before their life limits approach.

So the answer is maybe, but we won't see it.
 
Structures crack and corrode every day loaded to the brim with weight or not. It doesn't matter.

Overweight people = cracked floor boards, door steps, seat pans and armrests.
 
Last edited:
JHW said:
airlines have always operated at gross, full seats or empty seats. They have cargo sitting there ready to go and if there is extra weight available it gets loaded
Click to expand...
Airliners are rarely operated at max gross weight, even when the seats are full.
 
Henning said:
:confused: I'm not real sure that the first statement is supported by the second as applied to the real world. Airlines haven't been particularly profitable since deregulation and are often caught cutting corners on maintenance.
Click to expand...

Not really true. Things do get missed but very seldom is it the result of a conscious overt act to cut corners. It is very very rare.

JHW said:
airlines have always operated at gross, full seats or empty seats. They have cargo sitting there ready to go and if there is extra weight available it gets loaded
Click to expand...

This is absolutely the most accurate statement on this thread. :yes:
Very often the only difference between two aircraft is where the load is. On the main deck or in the cargo holds. If you want to make an argument that the cabin floor structure might be getting stressed more than before with higher pax counts and higher pax weights, then you might have at least a semi valid argument. As to flying near or at gross, it has been happening since day 1.

bnt83 said:
Structures crack and corrode every day loaded to the brim with weight or not. It doesn't matter.

Overweight people = cracked floor boards, door steps, seat pans and armrests.
Click to expand...

and bad knees. :sad:
 
Larry in TN said:
Airliners are rarely operated at max gross weight, even when the seats are full.
Click to expand...

That's a good point. I think I've taken off close to max gross twice in the last five months. Even with every seat full, we're typically 10% below max.
 
Ted DuPuis said:
Keep in mind that airliners are sold to 2nd and 3rd tier operators (in 3rd world countries) well before their life limits approach.

So the answer is maybe, but we won't see it.
Click to expand...

This is what I suspect to be the case. It will be interesting to see how long the US carriers choose to keep the airframes in service compared with the past. Of course those decisions are also based on the emergence of new technologies as well. My understanding is that most, if not all, new airliners are actually acquired through equipment leasing organizations anyhow. Is that not right? When the lease is up, then the leasing company sells it off to the foreign carriers, the 2nd their guys and maybe freight operators as well?

Anyhow, the forum consensus seems to be- fuggeddabout it. The engineers and their fancy pants computers got it covered. I was I guess kind hoping maybe there were some actual aircraft engineers that work for people like Boeing here that might chime in on if they actually do keep an eye on the progress of the fleet as it goes forward and if they consider the newer max gross every time with new designs on the drawing board? Anyhow, just a thought for a forum topic that occurred to me as I observed the airplanes I was flying on eat up more and more runway as they struggled for the air.
 
Almost every airplane I've ever flown seems to be easier to land at max gross.
 
Back to the OPs original observation regarding passenger loads - in a world of deregulation you don't make money with empty airplanes. Now you could bring back regulation but most think of cheap fares as a constitutionally guaranteed Right so I don't think that's gonna happen anytime soon.
 
JHW said:
airlines have always operated at gross, full seats or empty seats. They have cargo sitting there ready to go and if there is extra weight available it gets loaded
Click to expand...

Was this so back in the '80s and '90s as well? My observation is more a comparison between then and now. It seems like the planes now are eating up a lot of runway more than I remember in the past.
 
Dav8or said:
Was this so back in the '80s and '90s as well? My observation is more a comparison between then and now. It seems like the planes now are eating up a lot of runway more than I remember in the past.
Click to expand...

See my post above. The same was true whether they had any cargo or not.
 
I think everyone agrees that flying at gross is a non-starter. It's too late not to start, but let's end it now.

The question I heard from the OP related to airframe stress and lifespan. I don't think it's generally a US problem, although there have certainly been airframe stress issues - Aloha Air lost the skin around first class and Southwest had an depressurization on an older -300. But in general the airplanes are in good shape. We usually retire them before anything happens OR they get sold to overseas airlines. Perhaps they operate them well beyond their safe life, but we don't see foreign airlines disintegrating in mid air all that often either, do we?
 
Last edited:
Art VanDelay said:
Back to the OPs original observation regarding passenger loads - in a world of deregulation you don't make money with empty airplanes. Now you could bring back regulation but most think of cheap fares as a constitutionally guaranteed Right so I don't think that's gonna happen anytime soon.
Click to expand...

Oh I understand the economics of it, I'm just wondering what the impact of this new reality is on the equipment.
 
Dav8or said:
I don't know, do we know what happened officially with that Russian Airbus yet?
Click to expand...

No...but we DO know that it had been damaged previously and possibly repaired incorrectly and we also know, for sure, that an explosive would leave traces that are conclusive to a bomb. So this aircraft would be an exception. Would it not?
 
LDJones said:
That's a good point. I think I've taken off close to max gross twice in the last five months. Even with every seat full, we're typically 10% below max.
Click to expand...

Same here. Actually I'm not sure I've ever seen max gross.
 
Dav8or said:
Was this so back in the '80s and '90s as well? My observation is more a comparison between then and now. It seems like the planes now are eating up a lot of runway more than I remember in the past.
Click to expand...
what you are seeing are fuel saving measures including selecting the amount of power needed for each takeoff and not more
 
There's probably more to be concerned about 50-60 year old GA aircraft, poor logs, damage history missing, being flown with current owner not realizing something is wrong. I don't think the manufactures thought many of these would still be flying. Tube and fabric are different in that they can be totally stripped down and rebuilt , unlike an old bonanza say.
 
JHW said:
what you are seeing are fuel saving measures including selecting the amount of power needed for each takeoff and not more
Click to expand...

Engine savings more than fuel savings, but both benefit. Despite popular belief, turbines actually do wear faster the harder you run them. Partial power takeoffs are the norm now, as takeoff is actually a good part of the wear on a turbine. By using partial power, the airlines can go longer (often much, much longer) between pulling engines off wing.
 
Since the discussion has gone towards maintenance and cutting corners, some of you guys saying that they aren't being cut might wanna take a read. It's interesting, and somewhat frightening stuff. US Planes haven't started raining out of the skies yet, but if what this article says is true I have a feeling that there are going to be a couple big headline crashes that shake up the regulation of maintenance.

http://www.vanityfair.com/news/2015/11/airplane-maintenance-disturbing-truth
 
StinkBug said:
Since the discussion has gone towards maintenance and cutting corners, some of you guys saying that they aren't being cut might wanna take a read. It's interesting, and somewhat frightening stuff. US Planes haven't started raining out of the skies yet, but if what this article says is true I have a feeling that there are going to be a couple big headline crashes that shake up the regulation of maintenance.

http://www.vanityfair.com/news/2015/11/airplane-maintenance-disturbing-truth
Click to expand...
That article has a bit of fear mongering about international maintenance. Not like the US mx is necessarily better, two AA incidents come immediately to mind (the MD 80s a few years ago and the DC 10 that lost an engine at ORD in the 70s).

The FAA never could and really never can guarantee safety through its inspection program.
 
Jimmy cooper said:
There's probably more to be concerned about 50-60 year old GA aircraft, poor logs, damage history missing, being flown with current owner not realizing something is wrong. I don't think the manufactures thought many of these would still be flying. Tube and fabric are different in that they can be totally stripped down and rebuilt , unlike an old bonanza say.
Click to expand...

Well except for the fact that it doesn't have 150 people on it.
 
I don't see a problem. Maintenance at the airline level is intense to say the least.
I was also under the impression that the "life" of life limited parts was not determined by past in service history, but rather in "laboratory" conditions. I have heard (cannot confirm) that Cessna has some sort of "flex simulator machine" that keeps more hours on a stationary airframe than the highest time machine out there. Maybe somebody can confirm or bust that statement??
 
wsuffa said:
That article has a bit of fear mongering about international maintenance. Not like the US mx is necessarily better, two AA incidents come immediately to mind (the MD 80s a few years ago and the DC 10 that lost an engine at ORD in the 70s).

The FAA never could and really never can guarantee safety through its inspection program.
Click to expand...

There is some fear mongering going on there for sure, but if you're gonna use the DC-10 as an example, that crash was 45 years ago and changed the way a lot of things are done. At least here the FAA can pretend to have some power over quality of work, if only by giving the fear of an inspection. Sure things get missed no matter where it's being done, however after working in manufacturing and having to deal with the workmanship coming out of asian countries, that's the last place I'd be getting MY plane worked on.
 
Dav8or said:
It seems like the planes now are eating up a lot of runway more than I remember in the past.
Click to expand...
We have computers which calculate our takeoff profiles to use less flaps/higher speed profiles with bigger thrust reductions (from max). Pretty much extends every takeoff to fill the available runway.

JHW said:
what you are seeing are fuel saving measures including selecting the amount of power needed for each takeoff and not more
Click to expand...
Reduced thrust takeoffs actually burn more fuel than do max power takeoffs. The benefit is from the reduced temperatures in the turbine section which extend engine life.
 
Ted DuPuis said:
Engine savings more than fuel savings, but both benefit. Despite popular belief, turbines actually do wear faster the harder you run them. Partial power takeoffs are the norm now, as takeoff is actually a good part of the wear on a turbine. By using partial power, the airlines can go longer (often much, much longer) between pulling engines off wing.
Click to expand...

We use reduced thrust on 90% or more of our takeoffs. Only if the runway is short will we use normal. The savings on engines is significant according to our engine gurus.
 
StinkBug said:
There is some fear mongering going on there for sure, but if you're gonna use the DC-10 as an example, that crash was 45 years ago and changed the way a lot of things are done. At least here the FAA can pretend to have some power over quality of work, if only by giving the fear of an inspection. Sure things get missed no matter where it's being done, however after working in manufacturing and having to deal with the workmanship coming out of asian countries, that's the last place I'd be getting MY plane worked on.
Click to expand...

That DC10 was the result of an unapproved method being used in the engine removal process. The MD80s were clamps being installed improperly (just a few years ago).

The MX is done in shops in various locations that do it for multiple airlines, including some of the worlds best. Locations include Mexico and South America They still have to meet FAA standards. And the FAA still has the right to inspect. So the fear level really ought to be the same. That said, the airline safety record has been very, very good over the last decade, even with the outsourcing. For the most part, we're not talking Won's Car And Plane Repair.
 
You must log in or register to reply here.
Back
Top