Are airliners headed into uncharted territory?

Larry in TN said:
Airliners are rarely operated at max gross weight, even when the seats are full.
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Depends on the operation. At the carrier I flew the DC9 at, we flew at max takeoff weight quite a bit. Often it was a calculated max takeoff weight related to landing weight at the other end.
 
KSCessnaDriver said:
Depends on the operation. At the carrier I flew the DC9 at, we flew at max takeoff weight quite a bit. Often it was a calculated max takeoff weight related to landing weight at the other end.
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Yeah, you would think it would depend on how much paying freight is going that way. I remember going Chicago to Frankfurt on a Lufthansa 747 with 7 passengers on it (more crew than pax), I was 12 or so. I asked how they could afford to operate the flight. The captain told me the freight and mail below made the flight profitable before the first passenger loaded, and we had a major load in belly.
 
Silvaire said:
Well except for the fact that it doesn't have 150 people on it.
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Well.......except for the fact that GA accidents kill many more per year than U.S. Airlines do and there's thousands of these old crates flying. (I seem to recall some U.S. Airlines have been sued by the government for poor maintenence practices.)
 
wsuffa said:
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..
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The FAA has the right to inspect, but not the budget or manpower.

The out-sourced maintenance away from FAA scrutiny is a recipe for disaster, IMHO.

The way the airlines look at it is...why pay an FAA certified mechanic $25 per hour when you can get a common laborer in a foreign country who doesn't speak English and can't even read the tech manual $5 per day?

Follow the money. :yes:
 
KSCessnaDriver said:
Often it was a calculated max takeoff weight related to landing weight at the other end.
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That's not Max Gross weight which is what the OP was talking about. Most of my flights (B737 NG) are limited by other factors to something below MGTOW.
 
Larry in TN said:
That's not Max Gross weight which is what the OP was talking about. Most of my flights (B737 NG) are limited by other factors to something below MGTOW.
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God forbid we try to inform the sheep on how it works. Pardon me for trying to explain something.
 
Larry in TN said:
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.
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Good to know!! I had no idea that you were purposely using all the runway. I assumed it was due to the heavy weight. It sort of does address my thoughts on the newer era of operating heavier loads on a regular basis. I suspect that if they did take offs like the old days with the loads of today they would be going through engines and seeing failures.

This is why I started the thread. I was curious as to how things are being handled in this new era of every seat full every time. To make the system most efficient requires operating nearer to the limits of the design envelope than previous. To me this means every system is taxed a little harder.
 
MikeELP said:
In Mexico, China or El Salvador? :mad:
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MikeELP said:
The FAA has the right to inspect, but not the budget or manpower.

The out-sourced maintenance away from FAA scrutiny is a recipe for disaster, IMHO.

The way the airlines look at it is...why pay an FAA certified mechanic $25 per hour when you can get a common laborer in a foreign country who doesn't speak English and can't even read the tech manual $5 per day?

Follow the money. :yes:
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So, in your estimation, the situation is so bad that you personally have stopped flying commercial airlines for fear of your personal safety?
 
Dav8or said:
Good to know!! I had no idea that you were purposely using all the runway. I assumed it was due to the heavy weight. It sort of does address my thoughts on the newer era of operating heavier loads on a regular basis. I suspect that if they did take offs like the old days with the loads of today they would be going through engines and seeing failures.

This is why I started the thread. I was curious as to how things are being handled in this new era of every seat full every time. To make the system most efficient requires operating nearer to the limits of the design envelope than previous. To me this means every system is taxed a little harder.
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the weight is not dictated by the number of people in the seats. weights are no different today than they've ever been
 
Dav8or said:
*snip* I suspect that if they did take offs like the old days with the loads of today they would be going through engines and seeing failures.
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No more than they did in the old days. They just have better tech to manage the engines and make them last longer now.
 
Dav8or said:
Good to know!! I had no idea that you were purposely using all the runway. I assumed it was due to the heavy weight. It sort of does address my thoughts on the newer era of operating heavier loads on a regular basis. I suspect that if they did take offs like the old days with the loads of today they would be going through engines and seeing failures.

This is why I started the thread. I was curious as to how things are being handled in this new era of every seat full every time. To make the system most efficient requires operating nearer to the limits of the design envelope than previous. To me this means every system is taxed a little harder.
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While it's not a end of life failure, the Flight 90 crash does show what happens when this "save the engines" mentality overrides the "save the pax" mandate.

https://en.m.wikipedia.org/wiki/Air_Florida_Flight_90
 
Rubbish. The erroneous EPR indications due to iced sensors led the pilots to believe the engines were already producing max thrust. While they could have pushed the sticks further, in the few seconds of flight before the crash, the confusion caused by the lack of expected engine performance, poorly understood airspeed behavior, lift degradation due to airframe icing, and crew inexperience in severe winter weather conditions all contributed to the crash.

It had nothing to do with 'saving the engines'.
 
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warthog1984 said:
While it's not a end of life failure, the Flight 90 crash does show what happens when this "save the engines" mentality overrides the "save the pax" mandate.

https://en.m.wikipedia.org/wiki/Air_Florida_Flight_90
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That was a whole different deal. They didn't go full T/O power because they had erroneous readings on the instrumentation due to icing. The readings were full power, the readings were wrong though.
 
LDJones said:
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.
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Those engine gurus are correct, especially since they were probably told it by one of my former coworkers. ;)
 
Ted DuPuis said:
Those engine gurus are correct, especially since they were probably told it by one of my former coworkers. ;)
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On the other hand, our airplane doesn't have numbers for anything other than the takeoff detent. I know that is way more thrust than necessary in most cases. When I fly on a commercial airliners I definitely get the "rollin', rollin' rollin'" feeling. When are we going to rotate? We would be off the ground in 1/3 of the distance.
 
Henning said:
That doesn't only go for turbines either.
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Partial power takeoffs in pistons are almost universally a bad idea, though. We know that being kind to your engines helps, but the way to be kind is bykeeping temps happy, flying often, and typically 65% power.

Everskyward said:
On the other hand, our airplane doesn't have numbers for anything other than the takeoff detent. I know that is way more thrust than necessary in most cases. When I fly on a commercial airliners I definitely get the "rollin', rollin' rollin'" feeling. When are we going to rotate? We would be off the ground in 1/3 of the distance.
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Bizjet engines tend to not have engine life numbers published for derated takeoffs, so you can't legally factor those into your life/engine removal times. For airlines, you can actually extend life limits on parts by thousands of cycles and also extend the time between hot sections, since that's more typically governed by temps observed than hours/cycles in the airline world.
 
Ted DuPuis said:
Bizjet engines tend to not have engine life numbers published for derated takeoffs, so you can't legally factor those into your life/engine removal times. For airlines, you can actually extend life limits on parts by thousands of cycles and also extend the time between hot sections, since that's more typically governed by temps observed than hours/cycles in the airline world.
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Yeah, I don't think we can extend our overhaul time past the grace (I think that was 150 hours). We had the 3000 hour hot section about 6 months ago and they complimented us on the condition of the engines although we don't do anything special.
 
Everskyward said:
Yeah, I don't think we can extend our overhaul time past the grace (I think that was 150 hours). We had the 3000 hour hot section about 6 months ago and they complimented us on the condition of the engines although we don't do anything special.
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"I have very nice instruments! I've been complimented on my instruments!" :rofl:
 
I'd be more worried about the age and wear of other items then the airframe on the older airliners. I've had two planes in the last month have leaks in the windows or doors pressure seals. Nothing serious enough to depressurization but enough to **** off the poor guy sitting next to it. The one last week was loud enough from the cabin that I could hear it through my headset.

I think a pressure seal or door blowing out is more likely then a wing shearing off from age.
 
Everskyward said:
On the other hand, our airplane doesn't have numbers for anything other than the takeoff detent. I know that is way more thrust than necessary in most cases. When I fly on a commercial airliners I definitely get the "rollin', rollin' rollin'" feeling. When are we going to rotate? We would be off the ground in 1/3 of the distance.
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My understanding is that on our CRJ 700/900s the FADEC controls the output at the detent. If you select reduces thrust (what we call FLEX thrust), the FADEC automatically adjusts the power setting to the reduced amount when the thrust lever is pushed to the detent.

I'll verify that when I do my checkout on it next week.
 
LDJones said:
My understanding is that on our CRJ 700/900s the FADEC controls the output at the detent. If you select reduces thrust (what we call FLEX thrust), the FADEC automatically adjusts the power setting to the reduced amount when the thrust lever is pushed to the detent.

I'll verify that when I do my checkout on it next week.
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On our 145s the FADEC does everything in regards of thrust settings. On takeoff I set the levers at the detent and leave them there until cruise. We have four preset thrust buttons that are Climb, Cruise, Continuous, and Takeoff. Additionally the setting Takeoff can have as many as Three sub settings. They are "basically" Low, Medium and High.

99.999% of the time we takeoff in ALT-TO takeoff setting. Which is to extend the engine total life. On most runways it's not imperative to get off like a rocket.

When the PF calls for climb or cruise thrust I do nothing but press the associated button. The FADECs automatically rolls the power back, if the levers are still in the detent. The engine can still have upwards of 25% more power between the detent and balls to the wall position. So why use 100% on takeoff when it's almost never truly needed.
 
LDJones said:
My understanding is that on our CRJ 700/900s the FADEC controls the output at the detent. If you select reduces thrust (what we call FLEX thrust), the FADEC automatically adjusts the power setting to the reduced amount when the thrust lever is pushed to the detent.

I'll verify that when I do my checkout on it next week.
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Our FADEC controls the thrust output at the detent too, but the FADEC doesn't know our weight, or if we are taking off from a 4,000' long runway or a 14,000' long runway.
 
3393RP said:
Rubbish. The erroneous EPR indications due to iced sensors led the pilots to believe the engines were already producing max thrust. While they could have pushed the sticks further, in the few seconds of flight before the crash, the confusion caused by the lack of expected engine performance, poorly understood airspeed behavior, lift degradation due to airframe icing, and crew inexperience in severe winter weather conditions all contributed to the crash.

It had nothing to do with 'saving the engines'.
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The pilots at national had little or no experience flying in cold weather and it's true, they never opened the throttles all the way. They never should never have been there in the first place. The airline itself was operating on a shoestring. This accident finished it. It went bankrupt.
 
Everskyward said:
Our FADEC controls the thrust output at the detent too, but the FADEC doesn't know our weight, or if we are taking off from a 4,000' long runway or a 14,000' long runway.
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That's a disconnect I don't understand. Our FMS knows the runway we've selected and our TO weight. It even calculates the assumed temp for feeding the Flex power settings. Well, I guess technically the ACARS side knows all this and we have to manually feed it over to the FMS side. Seems like these could be much more efficiently integrated.
 
FX is still flying DC-10's. They're average age is 38yrs. Good luck finding a first world pax airline with airplanes that old.
 
LDJones said:
That's a disconnect I don't understand. Our FMS knows the runway we've selected and our TO weight. It even calculates the assumed temp for feeding the Flex power settings. Well, I guess technically the ACARS side knows all this and we have to manually feed it over to the FMS side. Seems like these could be much more efficiently integrated.
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I'm sure all this stuff can be integrated but it costs money to design, test, and build. I don't know about the economics of airlines, but business jet manufacturers need to keep their product within a certain price point so people will buy it. This is especially true of the Sovereign which is mid-sized and mid-priced. I don't hear about engines not making it to their hot section or TBO because of not doing reduced power takeoffs, so there is no reason to add that extra cost.
 
The missions for bizjets and airlines are completely different from an engine side. Identical engines installed on identical aircraft will have different life limits on turbomachinery if it's Bizjet vs commercial.

Because of these different mission profiles, the benefit of adding details into the FMS are reduced. In the airline world, those flight data stats can be used to extend the life of your engines. In the Bizjet world, they can't.

Bizjets tend to be more expensive than their airline counterparts (if those exist), but that's because of special interiors and other features that cost extra to do basically as one-offs.
 
ktup-flyer said:
FX is still flying DC-10's. They're average age is 38yrs. Good luck finding a first world pax airline with airplanes that old.
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Delta finally retired the DC-9's that they inherited from NW. The last DC-9 was built 32 years before retirement, some of the ones DL got were >40 years old.

So, yeah, some did run that old in pax service.

Older stuff has been retired now primarily over fuel and MX costs.
 
Ted DuPuis said:
The missions for bizjets and airlines are completely different from an engine side. Identical engines installed on identical aircraft will have different life limits on turbomachinery if it's Bizjet vs commercial.

Because of these different mission profiles, the benefit of adding details into the FMS are reduced. In the airline world, those flight data stats can be used to extend the life of your engines. In the Bizjet world, they can't.

Bizjets tend to be more expensive than their airline counterparts (if those exist), but that's because of special interiors and other features that cost extra to do basically as one-offs.
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There's also the thought that the original owner may or may not keep it all the way to the hot section inspection which is probably 6+ years down the road, and more unlikely to keep it to TBO which is more like 12+ years. At least that's the case with these engines.
 
LDJones said:
That's a disconnect I don't understand. Our FMS knows the runway we've selected and our TO weight. It even calculates the assumed temp for feeding the Flex power settings. Well, I guess technically the ACARS side knows all this and we have to manually feed it over to the FMS side. Seems like these could be much more efficiently integrated.
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It will soon enough, however be careful what you wish for, as the monkey in the cockpit is dependent on that system integration job.
 
Everskyward said:
There's also the thought that the original owner may or may not keep it all the way to the hot section inspection which is probably 6+ years down the road, and more unlikely to keep it to TBO which is more like 12+ years. At least that's the case with these engines.
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Excellent points, same reason most yachts are built like crap requiring major refit's every 5 years.
 
JHW said:
the weight is not dictated by the number of people in the seats. weights are no different today than they've ever been
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So basically you're saying that back in the '80s and '90s when I clearly remember riding around on airplanes that were half full of passengers, that those planes took off just as heavy as today because there was plenty of cargo sitting around to fill it up? :confused:
 
Dav8or said:
So basically you're saying that back in the '80s and '90s when I clearly remember riding around on airplanes that were half full of passengers, that those planes took off just as heavy as today because there was plenty of cargo sitting around to fill it up? :confused:
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Correct. Still happens, and in fact, critical cargo can bump pax since it pays better. People aren't really that heavy for the volume they require, cargo is king.
 
Henning said:
It will soon enough, however be careful what you wish for, as the monkey in the cockpit is dependent on that system integration job.
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Yeah, I don't think it will be too long before the automation is good enough that we will see single "pilot" ops in airliners where the pilot is just there to monitor the machine and make customers happy knowing there is a human "in charge".
 
Henning said:
Correct. Still happens, and in fact, critical cargo can bump pax since it pays better. People aren't really that heavy for the volume they require, cargo is king.
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So if cargo is more profitable and the airlines back then were carrying more cargo than passengers, why did so many airlines struggle financially? Why don't they today reduce the number of passengers they carry so they can carry more cargo?
 
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