kmaner
Topic Author
Posts: 3
Joined: Sat Feb 09, 2019 6:33 pm

Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 12:37 pm

What aircraft would Delta use to hot and high airports like Bogota once it could no longer use the 757s that it uses today?
 
MIflyer12
Posts: 4442
Joined: Mon Feb 18, 2013 11:58 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 1:06 pm

797s or Max8s, once the last of the 2004-2005-build 757s are gone.
 
Ziyulu
Posts: 377
Joined: Thu Oct 13, 2016 10:35 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 1:17 pm

Why wouldn't other planes work like the regular 737s or A320s?
 
RalXWB
Posts: 388
Joined: Sun Oct 25, 2015 9:36 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 1:21 pm

Production ended in 2004...
 
User avatar
afterburner
Posts: 1261
Joined: Mon Jun 13, 2005 11:38 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 1:29 pm

Ziyulu wrote:
Why wouldn't other planes work like the regular 737s or A320s?

https://en.wikipedia.org/wiki/Hot_and_high
 
kmaner
Topic Author
Posts: 3
Joined: Sat Feb 09, 2019 6:33 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 1:40 pm

Ziyulu... 737s and A320s would probably be weight restricted with a full load of passengers and cargo out of Bogota to Atlanta because of the altitude. Delta has on occasion used 737-700s for the ATL-BOG-ATL route but of course they carry a much smaller payload as compared to the 757-200s that Delta uses today.
 
xdlx
Posts: 909
Joined: Mon Aug 04, 2008 12:29 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 1:42 pm

A220 is already in Inventory!
 
User avatar
CarlosSi
Posts: 457
Joined: Sat Jul 08, 2017 8:29 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 2:10 pm

I noticed (on a similar note) AA cut MIA-SLLP, citing low demand, although I wonder if the 757 fleet reduction had anything to do with it. The flight always makes a stop in Viru Viru (I guess even La Paz’s high altitude might be too much for a 757!), so an a319 should’ve been able to make the route as well. MIA-BSB also comes into question.

DL doesn’t have a lot of hot and high routes that couldn’t be replaced by an a319 or 737-700 (JFK-MEX comes into question).
 
LatinAirliner
Posts: 22
Joined: Thu Jun 07, 2018 1:01 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 2:12 pm

Ziyulu wrote:
Why wouldn't other planes work like the regular 737s or A320s?


Yes they will work, BOG-ATL can be perfectly operated in an A320 or B737-700 / B737-800. But then they will reducing capacity, and I don't know if that is what they want. (including cargo capacity as well, an important one from BOG)
LatinAirliner - Nickpo
 
Ziyulu
Posts: 377
Joined: Thu Oct 13, 2016 10:35 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 2:30 pm

BOG's airport has a 3800 m runway. Please tell me a fully loaded A330 would have problems taking off and landing?
 
catiii
Posts: 2910
Joined: Mon Mar 31, 2008 1:18 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 2:51 pm

Ziyulu wrote:
BOG's airport has a 3800 m runway. Please tell me a fully loaded A330 would have problems taking off and landing?


I believe Avianca flies the 330 to JFK so don't think the 330 is a problem, but it isn't the right aircraft for DL to operate into BOG.
 
kmaner
Topic Author
Posts: 3
Joined: Sat Feb 09, 2019 6:33 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 3:42 pm

Yes, Avianca flies the A330 to deep South America, Miami and New York out of Bogota and they also used to fly them to Europe until they received the 787-8s. Delta could certainly fly the 737-700s as they have in the past but it would be a step down in capacity (both passengers and cargo). I'm not sure if a 737-800 or 737-900ER or A321 could operate out of Bogota to Atlanta fully loaded.
 
RCS763AV
Posts: 3762
Joined: Mon Jun 14, 2004 1:22 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 5:38 pm

Adding to the above, BOG-ATL could be easily doable by A32SNEO or B737MAX (these aircraft already fly BOG-EZE and BOG-JFK sectors which are considerably longer without significant payload restrictions). Isn't Delta receiving a bunch of NEOs in the coming years?
 
PSAatSAN4Ever
Posts: 413
Joined: Thu Sep 13, 2018 5:38 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 5:53 pm

CarlosSi wrote:
I noticed (on a similar note) AA cut MIA-SLLP, citing low demand, although I wonder if the 757 fleet reduction had anything to do with it. The flight always makes a stop in Viru Viru (I guess even La Paz’s high altitude might be too much for a 757!), so an a319 should’ve been able to make the route as well. MIA-BSB also comes into question.

DL doesn’t have a lot of hot and high routes that couldn’t be replaced by an a319 or 737-700 (JFK-MEX comes into question).


Airplanes operating into LPZ need to be specially equipped for extremely high altitudes, as on occasion, a landing plane has opened its doors only to have the oxygen masks fall, as the altitude at the airport was indeed higher than the cabin pressure, making the airplane believe it was an accidental depressurization.

And yes, despite the incredible performance of the 757, even its take-off abilities at 13,000+ feet are limited. However, my guess is that LPZ simply isn't premium-demand-heavy enough, so this route is better left to connecting carriers.
 
WayexTDI
Posts: 490
Joined: Fri Sep 21, 2018 4:38 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 5:58 pm

PSAatSAN4Ever wrote:
CarlosSi wrote:
I noticed (on a similar note) AA cut MIA-SLLP, citing low demand, although I wonder if the 757 fleet reduction had anything to do with it. The flight always makes a stop in Viru Viru (I guess even La Paz’s high altitude might be too much for a 757!), so an a319 should’ve been able to make the route as well. MIA-BSB also comes into question.

DL doesn’t have a lot of hot and high routes that couldn’t be replaced by an a319 or 737-700 (JFK-MEX comes into question).


Airplanes operating into LPZ need to be specially equipped for extremely high altitudes, as on occasion, a landing plane has opened its doors only to have the oxygen masks fall, as the altitude at the airport was indeed higher than the cabin pressure, making the airplane believe it was an accidental depressurization.

And yes, despite the incredible performance of the 757, even its take-off abilities at 13,000+ feet are limited. However, my guess is that LPZ simply isn't premium-demand-heavy enough, so this route is better left to connecting carriers.

Wouldn't that prevent the cabin doors from opening in the first place?
 
1989worstyear
Posts: 316
Joined: Sun Dec 04, 2016 6:53 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 9:21 pm

Ziyulu wrote:
Why wouldn't other planes work like the regular 737s or A320s?


Also, their existing A319, A320CEO, and 738 fleets are around the same age as their 752's (except for a few much newer 738's they inherited from Gol).

This is excluding the 1988 Factor though - the last A320 CEO could leave their fleet 15 years after the last 757 for all we know.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
gsg013
Posts: 428
Joined: Wed Feb 15, 2017 4:03 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 9:53 pm

What do you think will happen to the ATL-UIO flight which is at ~8000 feet altitude and also has steep terrain around the airport?

It is on the border of being a 767-300ER route I guess if DL gets the 797 it could be an option as well. I suppose the A319 could take over the flight as well.
 
N649DL
Posts: 289
Joined: Sat Aug 25, 2018 10:21 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 10:27 pm

kmaner wrote:
What aircraft would Delta use to hot and high airports like Bogota once it could no longer use the 757s that it uses today?


They just finished refurbishing all the 757s which I don't think are going away until cycles are up. Probably a nonissue for the next 3-5 years.

The 73G or 319 would be my best guess.
 
DLASFlyer
Posts: 29
Joined: Wed Jun 15, 2016 4:06 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 10:32 pm

They have replaced most of the 757 flying at JAC with A319s. I hope to see the A220 in JAC sometime if it is capable enough.
 
1989worstyear
Posts: 316
Joined: Sun Dec 04, 2016 6:53 pm

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 10:57 pm

N649DL wrote:
kmaner wrote:
What aircraft would Delta use to hot and high airports like Bogota once it could no longer use the 757s that it uses today?


They just finished refurbishing all the 757s which I don't think are going away until cycles are up. Probably a nonissue for the next 3-5 years.

The 73G or 319 would be my best guess.


Wouldn't the A319's also be due for replacement by that point? The newest one turned 15 in November - about the same age as the newest 752's.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
SurfandSnow
Posts: 1390
Joined: Sun Feb 01, 2009 7:09 am

Re: Delta 757s to hot and high airports - future?

Mon Feb 11, 2019 11:14 pm

DL has invested a tremendous amount of money into their 757s (-200s and -300s). I doubt these planes will be operating the likes of ATL-PNS for much longer, but routes like ATL-BOG/EGE that continue to capitalize on their capability, capacity and performance will probably continue to see them for years to come...
Flying in the middle seat of coach is much better than not flying at all!
 
N649DL
Posts: 289
Joined: Sat Aug 25, 2018 10:21 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 12:46 am

1989worstyear wrote:
N649DL wrote:
kmaner wrote:
What aircraft would Delta use to hot and high airports like Bogota once it could no longer use the 757s that it uses today?


They just finished refurbishing all the 757s which I don't think are going away until cycles are up. Probably a nonissue for the next 3-5 years.

The 73G or 319 would be my best guess.


Wouldn't the A319's also be due for replacement by that point? The newest one turned 15 in November - about the same age as the newest 752's.


Doubt it. Ex-NW 319s were delivered from 1999-2003 and were also all just refurbished with new interiors. Originally I think they were done so to do missions like ATL-UIO but are flying domestically instead.

The 757s have a much larger range. Some are from 2004 and quite a few others are from 1990-1991. What's crazy is how according to planespotters.net the A320s are older on average than the 757. 320s are average 23.5 years old and 757s are at 21.5.
 
Ziyulu
Posts: 377
Joined: Thu Oct 13, 2016 10:35 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 1:11 am

Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.
 
GalaxyFlyer
Posts: 2213
Joined: Fri Jan 01, 2016 4:44 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 1:15 am

WayexTDI wrote:
PSAatSAN4Ever wrote:
CarlosSi wrote:
I noticed (on a similar note) AA cut MIA-SLLP, citing low demand, although I wonder if the 757 fleet reduction had anything to do with it. The flight always makes a stop in Viru Viru (I guess even La Paz’s high altitude might be too much for a 757!), so an a319 should’ve been able to make the route as well. MIA-BSB also comes into question.

DL doesn’t have a lot of hot and high routes that couldn’t be replaced by an a319 or 737-700 (JFK-MEX comes into question).


Airplanes operating into LPZ need to be specially equipped for extremely high altitudes, as on occasion, a landing plane has opened its doors only to have the oxygen masks fall, as the altitude at the airport was indeed higher than the cabin pressure, making the airplane believe it was an accidental depressurization.

And yes, despite the incredible performance of the 757, even its take-off abilities at 13,000+ feet are limited. However, my guess is that LPZ simply isn't premium-demand-heavy enough, so this route is better left to connecting carriers.

Wouldn't that prevent the cabin doors from opening in the first place?


True, with the plane at SLLP and the cabin pressurized to 8,000-ish, no way is the door opening. And if Godzilla managed to force it, he’d be airborne on the outrushing air.


GF
 
WayexTDI
Posts: 490
Joined: Fri Sep 21, 2018 4:38 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 1:26 am

GalaxyFlyer wrote:
WayexTDI wrote:
PSAatSAN4Ever wrote:

Airplanes operating into LPZ need to be specially equipped for extremely high altitudes, as on occasion, a landing plane has opened its doors only to have the oxygen masks fall, as the altitude at the airport was indeed higher than the cabin pressure, making the airplane believe it was an accidental depressurization.

And yes, despite the incredible performance of the 757, even its take-off abilities at 13,000+ feet are limited. However, my guess is that LPZ simply isn't premium-demand-heavy enough, so this route is better left to connecting carriers.

Wouldn't that prevent the cabin doors from opening in the first place?


True, with the plane at SLLP and the cabin pressurized to 8,000-ish, no way is the door opening. And if Godzilla managed to force it, he’d be airborne on the outrushing air.


GF

That's what I thought. Which means that story about the masks dropping when the door opens doesn't make sense.
 
1989worstyear
Posts: 316
Joined: Sun Dec 04, 2016 6:53 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 1:42 am

N649DL wrote:
1989worstyear wrote:
N649DL wrote:

They just finished refurbishing all the 757s which I don't think are going away until cycles are up. Probably a nonissue for the next 3-5 years.

The 73G or 319 would be my best guess.


Wouldn't the A319's also be due for replacement by that point? The newest one turned 15 in November - about the same age as the newest 752's.


Doubt it. Ex-NW 319s were delivered from 1999-2003 and were also all just refurbished with new interiors. Originally I think they were done so to do missions like ATL-UIO but are flying domestically instead.

The 757s have a much larger range. Some are from 2004 and quite a few others are from 1990-1991. What's crazy is how according to planespotters.net the A320s are older on average than the 757. 320s are average 23.5 years old and 757s are at 21.5.


I'm not sure many people on here know - but there's only five (5) years between the A320 and 757 EIS. Also, NW was an early A320 customer, so it makes sense the remaining 752's are a few years newer on average.

Oh - and I was only referring to when the very last 752 (early 00's builds I hope) are retired - I would think the Babybuses would be on their way too. Assuming this, I would have to go with the A321N as the eventual replacement.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
DylanHarvey
Posts: 74
Joined: Thu Feb 01, 2018 5:45 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 2:44 am

Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.

The issue is that the airports are nearly 8,000ft above sea level, so engine thrust is limited, and therefore one engine climb out scenarios. So the weight of the aircraft needs to be restricted enough to where they can still maintain a certain rate of climb on one engine in the event of an engine failure after V1. And also temperatures can get high, and you generally need high performance because of obstacles around UIO and BOG.
 
N649DL
Posts: 289
Joined: Sat Aug 25, 2018 10:21 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 3:04 am

1989worstyear wrote:
N649DL wrote:
1989worstyear wrote:

Wouldn't the A319's also be due for replacement by that point? The newest one turned 15 in November - about the same age as the newest 752's.


Doubt it. Ex-NW 319s were delivered from 1999-2003 and were also all just refurbished with new interiors. Originally I think they were done so to do missions like ATL-UIO but are flying domestically instead.

The 757s have a much larger range. Some are from 2004 and quite a few others are from 1990-1991. What's crazy is how according to planespotters.net the A320s are older on average than the 757. 320s are average 23.5 years old and 757s are at 21.5.


I'm not sure many people on here know - but there's only five (5) years between the A320 and 757 EIS. Also, NW was an early A320 customer, so it makes sense the remaining 752's are a few years newer on average.

Oh - and I was only referring to when the very last 752 (early 00's builds I hope) are retired - I would think the Babybuses would be on their way too. Assuming this, I would have to go with the A321N as the eventual replacement.


Big age range on the A320 as well. The last one was delivered in 2002. Those early 90s frames I would think would be on their way out pretty soon.

The late 1990s / Early 2000s 757 and 319 I doubt you'll have to worry about leaving anytime soon. The early 90s frames with no winglets are probably on some sort of short term retirement timeline.
 
User avatar
Web500sjc
Posts: 754
Joined: Tue Sep 15, 2009 4:23 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 4:09 am

GalaxyFlyer wrote:
WayexTDI wrote:
PSAatSAN4Ever wrote:

Airplanes operating into LPZ need to be specially equipped for extremely high altitudes, as on occasion, a landing plane has opened its doors only to have the oxygen masks fall, as the altitude at the airport was indeed higher than the cabin pressure, making the airplane believe it was an accidental depressurization.

And yes, despite the incredible performance of the 757, even its take-off abilities at 13,000+ feet are limited. However, my guess is that LPZ simply isn't premium-demand-heavy enough, so this route is better left to connecting carriers.

Wouldn't that prevent the cabin doors from opening in the first place?


True, with the plane at SLLP and the cabin pressurized to 8,000-ish, no way is the door opening. And if Godzilla managed to force it, he’d be airborne on the outrushing air.


GF



When the A/C has weight on wheels, there should be a signal to open the outflow valve all the way, and completely equalize the inside and outside pressure, this allowing the door to be operated normally.

There is an old story about an Md-80 landing at RNO with the wrong altitude selected for the oressurization (I believe it was set for Sea level). When the aircraft landed, the out flow valve went to the full open position- causing an “explosive” equalization of the pressurization.
Boiler Up!
 
User avatar
Aesma
Posts: 10842
Joined: Sat Nov 14, 2009 6:14 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 6:39 am

Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.


Air is thinner so you need to go faster to fly. Is your landing gear designed to run on the runway at that higher speed ? I think that's a consideration at the highest airports at least.
New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
 
speedbird52
Posts: 408
Joined: Sat Nov 26, 2016 5:30 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 6:48 am

We should remember that this is the airline that retired the DC9 in 2014. If Delta need 757s they will keep them for as long as legally and safely possible
Proud to be a sl*t shamer of both sexes
 
speedbird52
Posts: 408
Joined: Sat Nov 26, 2016 5:30 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 6:49 am

Aesma wrote:
Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.


Air is thinner so you need to go faster to fly. Is your landing gear designed to run on the runway at that higher speed ? I think that's a consideration at the highest airports at least.

Isn't thrust to weight ratio another concern?
Proud to be a sl*t shamer of both sexes
 
N649DL
Posts: 289
Joined: Sat Aug 25, 2018 10:21 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 5:13 pm

speedbird52 wrote:
We should remember that this is the airline that retired the DC9 in 2014. If Delta need 757s they will keep them for as long as legally and safely possible


True but those were the NW DC-9-50 variants built in the late 1970s and kept in great shape through it's time with DL. They basically had 717 interiors and were replaced by them after DL purchased a ton from WN (DL even installed the D95s with new placards and leather seat covers.) DL only got rid of them because they got the 717 in combination with high fuel prices. The DC-9-30/40 were retired in 2010-2011, long before they got rid of the D95s.

Northwest MX best practices were enabled to DL as well. Probably why you can thank them for finding a recipe for keeping around 27-28 year old 757s right now.
 
airbazar
Posts: 9137
Joined: Wed Sep 10, 2003 11:12 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 6:14 pm

DylanHarvey wrote:
Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.

The issue is that the airports are nearly 8,000ft above sea level, so engine thrust is limited, and therefore one engine climb out scenarios. So the weight of the aircraft needs to be restricted enough to where they can still maintain a certain rate of climb on one engine in the event of an engine failure after V1. And also temperatures can get high, and you generally need high performance because of obstacles around UIO and BOG.

First of all, as someone pointed out this isn't going to be an issue any time soon as the 752's aren't about to be retired.
By that time DL should have NEO's in their fleet. BOG-IAH is 200nm longer and UA flies it with a 738, so IMO the A320NEO should have no problem and maybe even the A321NEO. PW gave the NEO engine a thrust bump specifically for these types of airports.
https://www.flightglobal.com/news/artic ... ed-399518/
DL has 100 A321NEO frames on order. I think it's obvious what they are replacing the 752's with ;)
 
LatinAirliner
Posts: 22
Joined: Thu Jun 07, 2018 1:01 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 6:35 pm

airbazar wrote:
DylanHarvey wrote:
Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.

The issue is that the airports are nearly 8,000ft above sea level, so engine thrust is limited, and therefore one engine climb out scenarios. So the weight of the aircraft needs to be restricted enough to where they can still maintain a certain rate of climb on one engine in the event of an engine failure after V1. And also temperatures can get high, and you generally need high performance because of obstacles around UIO and BOG.

First of all, as someone pointed out this isn't going to be an issue any time soon as the 752's aren't about to be retired.
By that time DL should have NEO's in their fleet. BOG-IAH is 200nm longer and UA flies it with a 738, so IMO the A320NEO should have no problem and maybe even the A321NEO. PW gave the NEO engine a thrust bump specifically for these types of airports.
https://www.flightglobal.com/news/artic ... ed-399518/
DL has 100 A321NEO frames on order. I think it's obvious what they are replacing the 752's with ;)


I think the A320NEO can make it BOG-ATL without a problem, I don't know it's performance and I don't have a guide to compare it with, but the closest route it comes to my mind is BOG-MCO. Avianca did operate a while last year the route in A320NEO and at least in PAX, they got full payload, don't know cargo.
LatinAirliner - Nickpo
 
B777LRF
Posts: 2245
Joined: Sun Nov 02, 2008 4:23 am

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 6:37 pm

DylanHarvey wrote:
Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.


The issue is that the airports are nearly 8,000ft above sea level, so engine thrust is limited, and therefore one engine climb out scenarios. So the weight of the aircraft needs to be restricted enough to where they can still maintain a certain rate of climb on one engine in the event of an engine failure after V1. And also temperatures can get high, and you generally need high performance because of obstacles around UIO and BOG.


That's one side of the issue, but there's something more fundamental at play.

Aircraft fly when the speed of the air flowing over the wings is sufficient to gain lift. This is measured as something called Indicated Air Speed (IAS). As the air pressure drops, less air flows over the wings for a given ground speed. In other words, if IAS at sea level equals Ground Speed (GS), then as the aircraft climbs the IAS will drop if the GS remain constant.

What this means taking off from a high-altitude airport is, that to gain sufficient lift for take-off you need a higher IAS than at sea level. This means your GS will also be higher, thus you need to cover more ground to gain sufficient lift. Hence the long runways at high-altitude airports.

But there's limits to how long a runway can be constructed, just as there are limits to how fast the tires of an airline is allowed to roll on the ground. That means you may end up in a situation where you can't reach the required IAS to gain lift, and the way to mitigate that problem is to reduce the weight of the aircraft. Which means either reducing the payload or introducing a technical stop enroute to refuel the aircraft. Most passenger airlines do the former for customer satisfaction reasons, must freight operators would chose the latter to maximise payload.

Speaking of the 737-800/900, it is not particularly well suited for high-altitude ops. They already operate with relatively high reference speeds for both take-off and landing, adding altitude to the situation only exacerbates that feature of the aircraft. Which means they may also be landing weight restricted. The 757 or, indeed, the A319 have much lower reference speeds. The A319 in particular has remarkably low reference speeds (consequence of flying on wings designed for the bigger A320 and the option of 27K motors), and that's just the ticket if you're taking off from or landing at high-altitude airports.
Signature. You just read one.
 
GSOtoIND
Posts: 22
Joined: Mon Aug 13, 2018 10:46 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 6:38 pm

Does anyone know if the 4 738s Delta bought from Gol have the SFP package? If so, those would be quite capable.
IND. 2018: BOS/AUA/MIA/DEN Next: LAS/SLC/DEN
 
DylanHarvey
Posts: 74
Joined: Thu Feb 01, 2018 5:45 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 7:55 pm

airbazar wrote:
DylanHarvey wrote:
Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.

The issue is that the airports are nearly 8,000ft above sea level, so engine thrust is limited, and therefore one engine climb out scenarios. So the weight of the aircraft needs to be restricted enough to where they can still maintain a certain rate of climb on one engine in the event of an engine failure after V1. And also temperatures can get high, and you generally need high performance because of obstacles around UIO and BOG.

First of all, as someone pointed out this isn't going to be an issue any time soon as the 752's aren't about to be retired.
By that time DL should have NEO's in their fleet. BOG-IAH is 200nm longer and UA flies it with a 738, so IMO the A320NEO should have no problem and maybe even the A321NEO. PW gave the NEO engine a thrust bump specifically for these types of airports.
https://www.flightglobal.com/news/artic ... ed-399518/
DL has 100 A321NEO frames on order. I think it's obvious what they are replacing the 752's with ;)

Yes, the A321neoACF will replace them, with 197 seats. Obviously won’t leave for BOG-ATL at MTOW, but will be able to perform profitably and cheaper than the beloved 752.
 
DylanHarvey
Posts: 74
Joined: Thu Feb 01, 2018 5:45 pm

Re: Delta 757s to hot and high airports - future?

Tue Feb 12, 2019 7:59 pm

B777LRF wrote:
DylanHarvey wrote:
Ziyulu wrote:
Something doesn't make sense here. Even though the airport is high, it has a 3800 m runway. So why would any 737 or 320 be a problem? You can load it to the max. That is a longer runway than at SFO where so many heavies take off and land without any problem.


The issue is that the airports are nearly 8,000ft above sea level, so engine thrust is limited, and therefore one engine climb out scenarios. So the weight of the aircraft needs to be restricted enough to where they can still maintain a certain rate of climb on one engine in the event of an engine failure after V1. And also temperatures can get high, and you generally need high performance because of obstacles around UIO and BOG.


That's one side of the issue, but there's something more fundamental at play.

Aircraft fly when the speed of the air flowing over the wings is sufficient to gain lift. This is measured as something called Indicated Air Speed (IAS). As the air pressure drops, less air flows over the wings for a given ground speed. In other words, if IAS at sea level equals Ground Speed (GS), then as the aircraft climbs the IAS will drop if the GS remain constant.

What this means taking off from a high-altitude airport is, that to gain sufficient lift for take-off you need a higher IAS than at sea level. This means your GS will also be higher, thus you need to cover more ground to gain sufficient lift. Hence the long runways at high-altitude airports.

But there's limits to how long a runway can be constructed, just as there are limits to how fast the tires of an airline is allowed to roll on the ground. That means you may end up in a situation where you can't reach the required IAS to gain lift, and the way to mitigate that problem is to reduce the weight of the aircraft. Which means either reducing the payload or introducing a technical stop enroute to refuel the aircraft. Most passenger airlines do the former for customer satisfaction reasons, must freight operators would chose the latter to maximise payload.

Speaking of the 737-800/900, it is not particularly well suited for high-altitude ops. They already operate with relatively high reference speeds for both take-off and landing, adding altitude to the situation only exacerbates that feature of the aircraft. Which means they may also be landing weight restricted. The 757 or, indeed, the A319 have much lower reference speeds. The A319 in particular has remarkably low reference speeds (consequence of flying on wings designed for the bigger A320 and the option of 27K motors), and that's just the ticket if you're taking off from or landing at high-altitude airports.

Yea correct, thank you for adding on. Yea the 73G is the best hot and high performer out of all the 737NG’s most likely, Delta has them configured with 27k engines for places like MEX and BOG, but the capacity is too small compared to a 752 or a 738, and the 321neo.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos