enzo011 wrote:

lightsaber wrote:

Just to be clear, hot is defined as 30C/86F when engines start to produce less thrust. As JNB isn't over 86F, engines produce full thrust and thus it is not hot. There is actually a technical threshold for hot. Yes, some engines that were Marginal on thust, such as initial CF6 on A330 (later PiP'd to 30C) had a 55F definition as hot, but that isn't the industry standard 30C/86F. High is any drop in barometric pressure reduces engine thrust and wing lift.

However, the A359 and 77L will both do fine at JNB as did RR powered A330s and many other Aircraft. JNB isn't a really tough spot. DXB with 114F and 600ft barrometric conditions is tougher (EK's infamous operating point for purchase decisions, which is pretty typical in the hot months).

So what is the engine performance like for the 77W out of DXB on a 114F day compared to the same 77W out of JNB at 77F but at its 5 558ft altitude? Is that even a valid comparison?

Have you looked at aircraft performance with altitude and temperature? Both Boeing and Airbus have extensive outlines:
http://www.boeing.com/commercial/airpor ... nuals.page


For the 777-200LR:
http://www.boeing.com/resources/boeingd ... 2lr3er.pdf

See slide 44 for altitude of 6,000 ft, the maximum takeoff weight of the 777-200LR is 705,000 lb or so (I'm eyeballing). So there is a reason DL did a morning takeoff as slide 45 shows us a hot day at JNB is way down at 685,000 lb (or so, again, I'm graph reading and there is some error).
If you look at slide 47, the hot day at sea level, at 114F, is about 730,000 lb, at 2000 ft only 685,000 lb, so I had it backward, the JNB takeoff means an allowed takeoff weight about 25,000 lb less than a hot day at Dubai (I find it telling Boeing now just publishes an easy way to interpolate the EK conditions). So a 777-200LR is taking off from JNB heavier in the morning than during EK's hot season.

So the GE-90-110 has enough spare margin to overcome.

It is a valid comparison as both impact takeoff performance.
Note: 766,000 lb MTOW just isn't going to be achieved under these conditions at either airport. .

A reduction of 55,000 lb in MTOW reduces the 777-200LR payload at range a little. Looking at slide 41 and knowing the OEW is about 320,000 lb (give or take) we see a non-fuel takeoff for 8500nm of 395,000 lb or so (again, eyeballing charts) or 75,000 lb of payload. At 105kg/pax (about 69,300lb) plus catering, crew, leaves about 4,000 lb for cargo above full pax on the 777.

Doing the same chart reading for the A359:
https://www.airbus.com/aircraft/support ... -data.html
https://www.airbus.com/aircraft/support ... stics.html
Looking at slide 158, we see at 6,000 ft, the A359 Maximum takeoff weight is 600,000 lb or so.

Slide 155 shows for 617,000 lb takeoff weight max pax could be taken out to 7,800nm. In other words, for JNB-ATL (or JFK), the flight must stop for fuel.

Airbus provides less information to non-paying customers (but far more in a bid, I've been amazed at the spreadsheets generated by airlines where they model every existing route cost and a bunch of future possible routes and buy aircraft on which has the least cost). They even model breaking down fleets (replace with 2 sizes instead of one, or cost of subfleets).

I even looked at the 789. From 6,000 ft, max takeoff of 458,000 lb. Oh... Not a great pick from JNB...

Delta needs an A359 with more thrust at altitude. A lot more thrust. More than any project I'm aware of. Cest la vie. They'll make it work with a refueling stop at lower altitude.

Lightsaber

lightsaber wrote:

Didn't SA's JNB-JFK fly nonstop?

lightsaber wrote:

enzo011 wrote:

lightsaber wrote:

Just to be clear, hot is defined as 30C/86F when engines start to produce less thrust. As JNB isn't over 86F, engines produce full thrust and thus it is not hot. There is actually a technical threshold for hot. Yes, some engines that were Marginal on thust, such as initial CF6 on A330 (later PiP'd to 30C) had a 55F definition as hot, but that isn't the industry standard 30C/86F. High is any drop in barometric pressure reduces engine thrust and wing lift.

However, the A359 and 77L will both do fine at JNB as did RR powered A330s and many other Aircraft. JNB isn't a really tough spot. DXB with 114F and 600ft barrometric conditions is tougher (EK's infamous operating point for purchase decisions, which is pretty typical in the hot months).

So what is the engine performance like for the 77W out of DXB on a 114F day compared to the same 77W out of JNB at 77F but at its 5 558ft altitude? Is that even a valid comparison?

Have you looked at aircraft performance with altitude and temperature? Both Boeing and Airbus have extensive outlines:
http://www.boeing.com/commercial/airpor ... nuals.page


For the 777-200LR:
http://www.boeing.com/resources/boeingd ... 2lr3er.pdf

See slide 44 for altitude of 6,000 ft, the maximum takeoff weight of the 777-200LR is 705,000 lb or so (I'm eyeballing). So there is a reason DL did a morning takeoff as slide 45 shows us a hot day at JNB is way down at 685,000 lb (or so, again, I'm graph reading and there is some error).
If you look at slide 47, the hot day at sea level, at 114F, is about 730,000 lb, at 2000 ft only 685,000 lb, so I had it backward, the JNB takeoff means an allowed takeoff weight about 25,000 lb less than a hot day at Dubai (I find it telling Boeing now just publishes an easy way to interpolate the EK conditions). So a 777-200LR is taking off from JNB heavier in the morning than during EK's hot season.

So the GE-90-110 has enough spare margin to overcome.

It is a valid comparison as both impact takeoff performance.
Note: 766,000 lb MTOW just isn't going to be achieved under these conditions at either airport. .

A reduction of 55,000 lb in MTOW reduces the 777-200LR payload at range a little. Looking at slide 41 and knowing the OEW is about 320,000 lb (give or take) we see a non-fuel takeoff for 8500nm of 395,000 lb or so (again, eyeballing charts) or 75,000 lb of payload. At 105kg/pax (about 69,300lb) plus catering, crew, leaves about 4,000 lb for cargo above full pax on the 777.

Doing the same chart reading for the A359:
https://www.airbus.com/aircraft/support ... -data.html
https://www.airbus.com/aircraft/support ... stics.html
Looking at slide 158, we see at 6,000 ft, the A359 Maximum takeoff weight is 600,000 lb or so.

Slide 155 shows for 617,000 lb takeoff weight max pax could be taken out to 7,800nm. In other words, for JNB-ATL (or JFK), the flight must stop for fuel.

Airbus provides less information to non-paying customers (but far more in a bid, I've been amazed at the spreadsheets generated by airlines where they model every existing route cost and a bunch of future possible routes and buy aircraft on which has the least cost). They even model breaking down fleets (replace with 2 sizes instead of one, or cost of subfleets).

I even looked at the 789. From 6,000 ft, max takeoff of 458,000 lb. Oh... Not a great pick from JNB...

Delta needs an A359 with more thrust at altitude. A lot more thrust. More than any project I'm aware of. Cest la vie. They'll make it work with a refueling stop at lower altitude.

Lightsaber

Great analysis. What reason do you think the 789 gets such a massive reduction to MTOW compared to the 77L and A359?

MrHMSH wrote:

lightsaber wrote:

Didn't SA's JNB-JFK fly nonstop?

When I flew it (2005?), it was non-stop JFK-JNB, but a stop in Dakar coming back.

ILikeTrains wrote:

lightsaber wrote:

enzo011 wrote:

So what is the engine performance like for the 77W out of DXB on a 114F day compared to the same 77W out of JNB at 77F but at its 5 558ft altitude? Is that even a valid comparison?

Have you looked at aircraft performance with altitude and temperature? Both Boeing and Airbus have extensive outlines:
http://www.boeing.com/commercial/airpor ... nuals.page


For the 777-200LR:
http://www.boeing.com/resources/boeingd ... 2lr3er.pdf

See slide 44 for altitude of 6,000 ft, the maximum takeoff weight of the 777-200LR is 705,000 lb or so (I'm eyeballing). So there is a reason DL did a morning takeoff as slide 45 shows us a hot day at JNB is way down at 685,000 lb (or so, again, I'm graph reading and there is some error).
If you look at slide 47, the hot day at sea level, at 114F, is about 730,000 lb, at 2000 ft only 685,000 lb, so I had it backward, the JNB takeoff means an allowed takeoff weight about 25,000 lb less than a hot day at Dubai (I find it telling Boeing now just publishes an easy way to interpolate the EK conditions). So a 777-200LR is taking off from JNB heavier in the morning than during EK's hot season.

So the GE-90-110 has enough spare margin to overcome.

It is a valid comparison as both impact takeoff performance.
Note: 766,000 lb MTOW just isn't going to be achieved under these conditions at either airport. .

A reduction of 55,000 lb in MTOW reduces the 777-200LR payload at range a little. Looking at slide 41 and knowing the OEW is about 320,000 lb (give or take) we see a non-fuel takeoff for 8500nm of 395,000 lb or so (again, eyeballing charts) or 75,000 lb of payload. At 105kg/pax (about 69,300lb) plus catering, crew, leaves about 4,000 lb for cargo above full pax on the 777.

Doing the same chart reading for the A359:
https://www.airbus.com/aircraft/support ... -data.html
https://www.airbus.com/aircraft/support ... stics.html
Looking at slide 158, we see at 6,000 ft, the A359 Maximum takeoff weight is 600,000 lb or so.

Slide 155 shows for 617,000 lb takeoff weight max pax could be taken out to 7,800nm. In other words, for JNB-ATL (or JFK), the flight must stop for fuel.

Airbus provides less information to non-paying customers (but far more in a bid, I've been amazed at the spreadsheets generated by airlines where they model every existing route cost and a bunch of future possible routes and buy aircraft on which has the least cost). They even model breaking down fleets (replace with 2 sizes instead of one, or cost of subfleets).

I even looked at the 789. From 6,000 ft, max takeoff of 458,000 lb. Oh... Not a great pick from JNB...

Delta needs an A359 with more thrust at altitude. A lot more thrust. More than any project I'm aware of. Cest la vie. They'll make it work with a refueling stop at lower altitude.

Lightsaber

Great analysis. What reason do you think the 789 gets such a massive reduction to MTOW compared to the 77L and A359?

My guess would be that the 787-9 is more rotation angle limited (short landing gears on the 787) than either the 777-200LR or A350-900. It's telling that the 787-10 needed to leverage the 777-300ER's semi-cantilevered gear design to have acceptable field performance even at normal airports.

So based on the number of A350's that DL has in their fleet, have they already surpassed the 777 fleet, its not as if DL is a large operator of the 777, of course because it is DL, the resale value of the 777 will take a hit.

Not as yet...Dal has 18 B777 and just 13 A350's on property currently......#14 is currently on the flightline in France

par13del wrote:

So based on the number of A350's that DL has in their fleet, have they already surpassed the 777 fleet, its not as if DL is a large operator of the 777, of course because it is DL, the resale value of the 777 will take a hit.

par13del wrote:

So based on the number of A350's that DL has in their fleet, have they already surpassed the 777 fleet, its not as if DL is a large operator of the 777, of course because it is DL, the resale value of the 777 will take a hit.

The 77E has no real resale value now with most retirees being scrapped. There hasn't ever been a resale for 77L with airlines such as AI and EY both struggling to shift theirs. Realistically, unless the sums add up for a freighter conversion, it is likely these will sit in the desert and eventually be scrapped.

alfa164 wrote:

MrHMSH wrote:

lightsaber wrote:

Didn't SA's JNB-JFK fly nonstop?

When I flew it (2005?), it was non-stop JFK-JNB, but a stop in Dakar coming back.

I meant for the A359 specifically, it replaced the A346 which had/has different capabilities.

lightsaber wrote:

So what is the engine performance like for the 77W out of DXB on a 114F day compared to the same 77W out of JNB at 77F but at its 5 558ft altitude?

I have no time to do extensive check, so forgive me if you did the check (you probably did).

The problem with JNB is not only high. Everyone is considering it hot, not because of +30C, but because you have to reference to 6000ft ISA atmosphere. So, basically cool 20C is ISA+17.
Agreed it's not a problem for engine (you just loose some percent of thrust lost due to lower airflow at this altitude), but certainly double impact on airframe.

Cheers,
Adam

lightsaber wrote:

For the 777-200LR:
http://www.boeing.com/resources/boeingd ... 2lr3er.pdf

See slide 44 for altitude of 6,000 ft, the maximum takeoff weight of the 777-200LR is 705,000 lb or so (I'm eyeballing). So there is a reason DL did a morning takeoff as slide 45 shows us a hot day at JNB is way down at 685,000 lb (or so, again, I'm graph reading and there is some error).
If you look at slide 47, the hot day at sea level, at 114F, is about 730,000 lb, at 2000 ft only 685,000 lb, so I had it backward, the JNB takeoff means an allowed takeoff weight about 25,000 lb less than a hot day at Dubai (I find it telling Boeing now just publishes an easy way to interpolate the EK conditions). So a 777-200LR is taking off from JNB heavier in the morning than during EK's hot season.

So the GE-90-110 has enough spare margin to overcome.

It is a valid comparison as both impact takeoff performance.
Note: 766,000 lb MTOW just isn't going to be achieved under these conditions at either airport. .

A reduction of 55,000 lb in MTOW reduces the 777-200LR payload at range a little. Looking at slide 41 and knowing the OEW is about 320,000 lb (give or take) we see a non-fuel takeoff for 8500nm of 395,000 lb or so (again, eyeballing charts) or 75,000 lb of payload. At 105kg/pax (about 69,300lb) plus catering, crew, leaves about 4,000 lb for cargo above full pax on the 777.

Lightsaber

Hi Lightsaber.

I have dispatched the JNB-ATL flight only occasionally but your weight/payload analysis for the 777LR is pretty accurate. A couple things to add.

- The flight arrived mid-morning and departed JNB in the early evening. Due to the elevation, the performance was extremely sensitive to temperature and barometric pressure. Even though it departed after the hottest part of the day, the temperature was always watched very closely. If the evening temps did not fall as forecast you could loose a significant amount of payload margin you were counting on.

- Another complication was the wind. You would have shifting or variable winds in the evening as the sun went down or if there was convective activity in the vicinity, especially in the summertime. A tailwind of only a knot or two would reduce your RATOW by several thousand pounds. Not unique to the 777LR but it had a greater impact since you were almost always planning up to the performance limit. Like many airports, JNB would usually not change runways until the tailwind exceeded 10kts. You could request an opposite direction takeoff from ATC but would most likely take a significant delay waiting for a gap in traffic.

Of course, the sea-level departure on the CPT-ATL leg will reduce if not eliminate most of these concerns but I will be curious to see how the A350 actually does on the route.

That being said, I am saddened by the retirement of the 777 from DL even though it makes sense in the current conditions. They are an extremely capable aircraft and easy to work from a dispatch standpoint. The 777LR in particular is a payload monster. I've always been amazed that the 777LR has a higher MTOW than the original 747-100.

lightsaber wrote:

Have you looked at aircraft performance with altitude and temperature? Both Boeing and Airbus have extensive outlines:
http://www.boeing.com/commercial/airpor ... nuals.page


For the 777-200LR:
http://www.boeing.com/resources/boeingd ... 2lr3er.pdf

See slide 44 for altitude of 6,000 ft, the maximum takeoff weight of the 777-200LR is 705,000 lb or so (I'm eyeballing). So there is a reason DL did a morning takeoff as slide 45 shows us a hot day at JNB is way down at 685,000 lb (or so, again, I'm graph reading and there is some error).
If you look at slide 47, the hot day at sea level, at 114F, is about 730,000 lb, at 2000 ft only 685,000 lb, so I had it backward, the JNB takeoff means an allowed takeoff weight about 25,000 lb less than a hot day at Dubai (I find it telling Boeing now just publishes an easy way to interpolate the EK conditions). So a 777-200LR is taking off from JNB heavier in the morning than during EK's hot season.

So the GE-90-110 has enough spare margin to overcome.

It is a valid comparison as both impact takeoff performance.
Note: 766,000 lb MTOW just isn't going to be achieved under these conditions at either airport. .

A reduction of 55,000 lb in MTOW reduces the 777-200LR payload at range a little. Looking at slide 41 and knowing the OEW is about 320,000 lb (give or take) we see a non-fuel takeoff for 8500nm of 395,000 lb or so (again, eyeballing charts) or 75,000 lb of payload. At 105kg/pax (about 69,300lb) plus catering, crew, leaves about 4,000 lb for cargo above full pax on the 777.

Doing the same chart reading for the A359:
https://www.airbus.com/aircraft/support ... -data.html
https://www.airbus.com/aircraft/support ... stics.html
Looking at slide 158, we see at 6,000 ft, the A359 Maximum takeoff weight is 600,000 lb or so.

Slide 155 shows for 617,000 lb takeoff weight max pax could be taken out to 7,800nm. In other words, for JNB-ATL (or JFK), the flight must stop for fuel.

Airbus provides less information to non-paying customers (but far more in a bid, I've been amazed at the spreadsheets generated by airlines where they model every existing route cost and a bunch of future possible routes and buy aircraft on which has the least cost). They even model breaking down fleets (replace with 2 sizes instead of one, or cost of subfleets).

I even looked at the 789. From 6,000 ft, max takeoff of 458,000 lb. Oh... Not a great pick from JNB...

Delta needs an A359 with more thrust at altitude. A lot more thrust. More than any project I'm aware of. Cest la vie. They'll make it work with a refueling stop at lower altitude.

Lightsaber

Thank you for the reply. You seem to indicate that the 77L loses more weight out of JNB due to the altitude than temperature out of DXB, right?

If we compare ISA +59F for the 77W the MTOW, if I eyeball the chart correctly it is able to carry 735 000lbs. If I eyeball ISA but at 6000ft it can take off at around 700 000lbs. So altitude out of JNB has a bigger influence on aircraft performance than temperature out of DXB, or am I reading that incorrectly?

tullamarine wrote:

There hasn't ever been a resale for 77L with airlines such as AI and EY both struggling to shift theirs.

Not true. EY having the 77L in their fleet was literally a purchase from Air India itself.

par13del wrote:

... its not as if DL is a large operator of the 777, of course ...

Slightly off-topic but I think I'm right that they intended to have many more.

https://www.flightglobal.com/rolls-royc ... 63.article

"Rolls-Royce has beaten GE and Pratt & Whitney in a contest to supply its Trent 800s to power 10 Delta Air Lines' Boeing 777s (with firm options on a further 20 and rolling options on 30 more)." 15th November 1997.

But then Delta got into a dispute with their pilots and only a few planes were delivered. Undelivered orders were subsequently converted to the 777-200LR.

But 60 777s with RR for Delta. What might have been...

PM wrote:

par13del wrote:

... its not as if DL is a large operator of the 777, of course ...

Slightly off-topic but I think I'm right that they intended to have many more.

https://www.flightglobal.com/rolls-royc ... 63.article

"Rolls-Royce has beaten GE and Pratt & Whitney in a contest to supply its Trent 800s to power 10 Delta Air Lines' Boeing 777s (with firm options on a further 20 and rolling options on 30 more)." 15th November 1997.

But then Delta got into a dispute with their pilots and only a few planes were delivered. Undelivered orders were subsequently converted to the 777-200LR.

But 60 777s with RR for Delta. What might have been...

That is interesting, though I am not sure what DL would have done with all those 777s had they taken more. For several years in the early 2000s the only route DL flew that truly needed the 777 was ATL-NRT; the other 777s were doing ATL (and potentially even CVG?) to Europe.

N831MH planned to be deployed for the re-instated DL46

Source: https://www.flightstats.com/v2/flight-d ... 1038083643

Can the suites and the Y seats from the 777 fleet be re used on the Airbus wide bodies ?

I know the PY seats and IFE units should not have a problem, but what about the suites

Regards/

Karan

karan69 wrote:

Can the suites and the Y seats from the 777 fleet be re used on the Airbus wide bodies ?

I know the PY seats and IFE units should not have a problem, but what about the suites

Regards/

Karan

The Y seats won’t fit on the Airbuses, unsure about J.

karan69 wrote:

Can the suites and the Y seats from the 777 fleet be re used on the Airbus wide bodies ?

I know the PY seats and IFE units should not have a problem, but what about the suites

Regards/

Karan

I have to imagine they could modify the J seats in some way to use them, and the Y seats could be resold since there's nothing proprietary about them. The A350 Y seats are a unique design compared to the rest of the fleet.

The D1 Suites on the 777s as they currently are, are wider than those on the A359s, so they will not fit as-is. I have no idea how difficult or easy it would be to modify them (e.g., thinner door or frame) to fit on the A359s or if it's even possible at all.

dairbus wrote:

lightsaber wrote:

For the 777-200LR:
http://www.boeing.com/resources/boeingd ... 2lr3er.pdf

See slide 44 for altitude of 6,000 ft, the maximum takeoff weight of the 777-200LR is 705,000 lb or so (I'm eyeballing). So there is a reason DL did a morning takeoff as slide 45 shows us a hot day at JNB is way down at 685,000 lb (or so, again, I'm graph reading and there is some error).
If you look at slide 47, the hot day at sea level, at 114F, is about 730,000 lb, at 2000 ft only 685,000 lb, so I had it backward, the JNB takeoff means an allowed takeoff weight about 25,000 lb less than a hot day at Dubai (I find it telling Boeing now just publishes an easy way to interpolate the EK conditions). So a 777-200LR is taking off from JNB heavier in the morning than during EK's hot season.

So the GE-90-110 has enough spare margin to overcome.

It is a valid comparison as both impact takeoff performance.
Note: 766,000 lb MTOW just isn't going to be achieved under these conditions at either airport. .

A reduction of 55,000 lb in MTOW reduces the 777-200LR payload at range a little. Looking at slide 41 and knowing the OEW is about 320,000 lb (give or take) we see a non-fuel takeoff for 8500nm of 395,000 lb or so (again, eyeballing charts) or 75,000 lb of payload. At 105kg/pax (about 69,300lb) plus catering, crew, leaves about 4,000 lb for cargo above full pax on the 777.

Lightsaber

Hi Lightsaber.

I have dispatched the JNB-ATL flight only occasionally but your weight/payload analysis for the 777LR is pretty accurate. A couple things to add.

- The flight arrived mid-morning and departed JNB in the early evening. Due to the elevation, the performance was extremely sensitive to temperature and barometric pressure. Even though it departed after the hottest part of the day, the temperature was always watched very closely. If the evening temps did not fall as forecast you could loose a significant amount of payload margin you were counting on.

- Another complication was the wind. You would have shifting or variable winds in the evening as the sun went down or if there was convective activity in the vicinity, especially in the summertime. A tailwind of only a knot or two would reduce your RATOW by several thousand pounds. Not unique to the 777LR but it had a greater impact since you were almost always planning up to the performance limit. Like many airports, JNB would usually not change runways until the tailwind exceeded 10kts. You could request an opposite direction takeoff from ATC but would most likely take a significant delay waiting for a gap in traffic.

Of course, the sea-level departure on the CPT-ATL leg will reduce if not eliminate most of these concerns but I will be curious to see how the A350 actually does on the route.

That being said, I am saddened by the retirement of the 777 from DL even though it makes sense in the current conditions. They are an extremely capable aircraft and easy to work from a dispatch standpoint. The 777LR in particular is a payload monster. I've always been amazed that the 777LR has a higher MTOW than the original 747-100.

Thank you for that wonderful information.

Yes, the 77L is certainly a beast and it’s quite evident that DL can’t make it work on the JNB-ATL leg with the A350.

Fantastic airplane, but it just doesn’t quite have the balls to do this route, which is why they are stopping in CPT on the way home.

FriscoHeavy wrote:

dairbus wrote:

lightsaber wrote:

For the 777-200LR:
http://www.boeing.com/resources/boeingd ... 2lr3er.pdf

See slide 44 for altitude of 6,000 ft, the maximum takeoff weight of the 777-200LR is 705,000 lb or so (I'm eyeballing). So there is a reason DL did a morning takeoff as slide 45 shows us a hot day at JNB is way down at 685,000 lb (or so, again, I'm graph reading and there is some error).
If you look at slide 47, the hot day at sea level, at 114F, is about 730,000 lb, at 2000 ft only 685,000 lb, so I had it backward, the JNB takeoff means an allowed takeoff weight about 25,000 lb less than a hot day at Dubai (I find it telling Boeing now just publishes an easy way to interpolate the EK conditions). So a 777-200LR is taking off from JNB heavier in the morning than during EK's hot season.

So the GE-90-110 has enough spare margin to overcome.

It is a valid comparison as both impact takeoff performance.
Note: 766,000 lb MTOW just isn't going to be achieved under these conditions at either airport. .

A reduction of 55,000 lb in MTOW reduces the 777-200LR payload at range a little. Looking at slide 41 and knowing the OEW is about 320,000 lb (give or take) we see a non-fuel takeoff for 8500nm of 395,000 lb or so (again, eyeballing charts) or 75,000 lb of payload. At 105kg/pax (about 69,300lb) plus catering, crew, leaves about 4,000 lb for cargo above full pax on the 777.

Lightsaber

Hi Lightsaber.

I have dispatched the JNB-ATL flight only occasionally but your weight/payload analysis for the 777LR is pretty accurate. A couple things to add.

- The flight arrived mid-morning and departed JNB in the early evening. Due to the elevation, the performance was extremely sensitive to temperature and barometric pressure. Even though it departed after the hottest part of the day, the temperature was always watched very closely. If the evening temps did not fall as forecast you could loose a significant amount of payload margin you were counting on.

- Another complication was the wind. You would have shifting or variable winds in the evening as the sun went down or if there was convective activity in the vicinity, especially in the summertime. A tailwind of only a knot or two would reduce your RATOW by several thousand pounds. Not unique to the 777LR but it had a greater impact since you were almost always planning up to the performance limit. Like many airports, JNB would usually not change runways until the tailwind exceeded 10kts. You could request an opposite direction takeoff from ATC but would most likely take a significant delay waiting for a gap in traffic.

Of course, the sea-level departure on the CPT-ATL leg will reduce if not eliminate most of these concerns but I will be curious to see how the A350 actually does on the route.

That being said, I am saddened by the retirement of the 777 from DL even though it makes sense in the current conditions. They are an extremely capable aircraft and easy to work from a dispatch standpoint. The 777LR in particular is a payload monster. I've always been amazed that the 777LR has a higher MTOW than the original 747-100.

Thank you for that wonderful information.

Yes, the 77L is certainly a beast and it’s quite evident that DL can’t make it work on the JNB-ATL leg with the A350.

Fantastic airplane, but it just doesn’t quite have the balls to do this route, which is why they are stopping in CPT on the way home.

It just can’t do it with the payload DL wanted. As a matter of fact, the 77L might be the only aircraft in the world that can do this route with a heavy-ish payload. An A35K with a thrust bump is interesting though.

SA has flown the A359 JNB-JFK but the route is 409 nm shorter than JNB-ATL which is about an hour less flight time. The A359 is very good but JNB-JFK is one of the most challenging in the world. It is no disgrace it has to do a stop at CPT.

ElroyJetson wrote:

SA has flown the A359 JNB-JFK but the route is 409 nm shorter than JNB-ATL which is about an hour less flight time. The A359 is very good but JNB-JFK is one of the most challenging in the world. It is no disgrace it has to do a stop at CPT.

DL have slightly higher fuel reserve requirements as well IIRC. So when a flight is already at the performance edge, ~15-17hrs at 5500ft, any extra payload or weight thats necessary is not gonna help much.

DylanHarvey wrote:

FriscoHeavy wrote:

dairbus wrote:

Hi Lightsaber.

I have dispatched the JNB-ATL flight only occasionally but your weight/payload analysis for the 777LR is pretty accurate. A couple things to add.

- The flight arrived mid-morning and departed JNB in the early evening. Due to the elevation, the performance was extremely sensitive to temperature and barometric pressure. Even though it departed after the hottest part of the day, the temperature was always watched very closely. If the evening temps did not fall as forecast you could loose a significant amount of payload margin you were counting on.

- Another complication was the wind. You would have shifting or variable winds in the evening as the sun went down or if there was convective activity in the vicinity, especially in the summertime. A tailwind of only a knot or two would reduce your RATOW by several thousand pounds. Not unique to the 777LR but it had a greater impact since you were almost always planning up to the performance limit. Like many airports, JNB would usually not change runways until the tailwind exceeded 10kts. You could request an opposite direction takeoff from ATC but would most likely take a significant delay waiting for a gap in traffic.

Of course, the sea-level departure on the CPT-ATL leg will reduce if not eliminate most of these concerns but I will be curious to see how the A350 actually does on the route.

That being said, I am saddened by the retirement of the 777 from DL even though it makes sense in the current conditions. They are an extremely capable aircraft and easy to work from a dispatch standpoint. The 777LR in particular is a payload monster. I've always been amazed that the 777LR has a higher MTOW than the original 747-100.

Thank you for that wonderful information.

Yes, the 77L is certainly a beast and it’s quite evident that DL can’t make it work on the JNB-ATL leg with the A350.

Fantastic airplane, but it just doesn’t quite have the balls to do this route, which is why they are stopping in CPT on the way home.

It just can’t do it with the payload DL wanted. As a matter of fact, the 77L might be the only aircraft in the world that can do this route with a heavy-ish payload. An A35K with a thrust bump is interesting though.

And the A346. The A35K at 319t probably could do it but in Deltas configuration it would be close to 50 more seats than the 777L. Doubt Delta wants that big of an increase.

DCA350 wrote:

DylanHarvey wrote:

FriscoHeavy wrote:

Thank you for that wonderful information.

Yes, the 77L is certainly a beast and it’s quite evident that DL can’t make it work on the JNB-ATL leg with the A350.

Fantastic airplane, but it just doesn’t quite have the balls to do this route, which is why they are stopping in CPT on the way home.

It just can’t do it with the payload DL wanted. As a matter of fact, the 77L might be the only aircraft in the world that can do this route with a heavy-ish payload. An A35K with a thrust bump is interesting though.

And the A346. The A35K at 319t probably could do it but in Deltas configuration it would be close to 50 more seats than the 777L. Doubt Delta wants that big of an increase.

Yeah, kinda forgot about the 346 momentarily, she gets MTOW from Jo’Burg more often than not. I wish I got to fly on one we would probably see them have a similar configuration to Cathay. Maybe 340 ish

DylanHarvey wrote:

FriscoHeavy wrote:

dairbus wrote:

Hi Lightsaber.

I have dispatched the JNB-ATL flight only occasionally but your weight/payload analysis for the 777LR is pretty accurate. A couple things to add.

- The flight arrived mid-morning and departed JNB in the early evening. Due to the elevation, the performance was extremely sensitive to temperature and barometric pressure. Even though it departed after the hottest part of the day, the temperature was always watched very closely. If the evening temps did not fall as forecast you could loose a significant amount of payload margin you were counting on.

- Another complication was the wind. You would have shifting or variable winds in the evening as the sun went down or if there was convective activity in the vicinity, especially in the summertime. A tailwind of only a knot or two would reduce your RATOW by several thousand pounds. Not unique to the 777LR but it had a greater impact since you were almost always planning up to the performance limit. Like many airports, JNB would usually not change runways until the tailwind exceeded 10kts. You could request an opposite direction takeoff from ATC but would most likely take a significant delay waiting for a gap in traffic.

Of course, the sea-level departure on the CPT-ATL leg will reduce if not eliminate most of these concerns but I will be curious to see how the A350 actually does on the route.

That being said, I am saddened by the retirement of the 777 from DL even though it makes sense in the current conditions. They are an extremely capable aircraft and easy to work from a dispatch standpoint. The 777LR in particular is a payload monster. I've always been amazed that the 777LR has a higher MTOW than the original 747-100.

Thank you for that wonderful information.

Yes, the 77L is certainly a beast and it’s quite evident that DL can’t make it work on the JNB-ATL leg with the A350.

Fantastic airplane, but it just doesn’t quite have the balls to do this route, which is why they are stopping in CPT on the way home.

It just can’t do it with the payload DL wanted. As a matter of fact, the 77L might be the only aircraft in the world that can do this route with a heavy-ish payload. An A35K with a thrust bump is interesting though.

I thank those who put forth the effort on range/payload calcs.

'It can fly it but without the payload' means it doesn't represent the same revenue opportunity. There's some value in being able to carry intercontinental freight, right?

DL has had enough A350s for a while now (and had deferred some even before COVID-19 or the LATAM A350 commitments), and still chose to use 77Ls on the route. That suggests they value payload capability more than the A350's fuel savings. (It might also suggest that DL simply had no better route for the 77Ls that were in the fleet...) It's hard to argue the costs of a pilot-specific subfleet (whether that's DL 777/77L or just the ten 77Ls) where the capability is needed on just one or two routes.

DL looks like it's finally getting serious about fleet simplification. As it shrinks that becomes even more of a priority. That's a long and expensive path unless you're just pulling out capacity and/or terminating outlier routes (distance, noise requirements, runway limitations, hot/high).

ElroyJetson wrote:

SA has flown the A359 JNB-JFK but the route is 409 nm shorter than JNB-ATL which is about an hour less flight time. The A359 is very good but JNB-JFK is one of the most challenging in the world. It is no disgrace it has to do a stop at CPT.

Considering Delta ran ATL-DKR-JNB and ATL-DKR-CPT for awhile on the 764/763, definitely no disgrace. They'll also be happy to get the higher A350 tonne variants off the line in Toulouse for it.

Just found out that 1705 is no longer in the SkyTeam livery. I wish they had kept that livery on a handful of planes but they have been re-painting those planes back into the normal livery.

The 4 remaining A359s in storage are now scheduled to leave BYH on Friday & Saturday. It appears all A359s will now be active.
https://flightaware.com/live/airport/KBYH/scheduled
2 BYH-DTW on Friday
2 BYH-MSP on Saturday

Are some of the DL 777s now parked already been retired permanently or is it planned to return all to service for a short time?

MIflyer12 wrote:

'It can fly it but without the payload' means it doesn't represent the same revenue opportunity. There's some value in being able to carry intercontinental freight, right?

Potential revenue is just that, potential.

While the A359 might not not be able to lift as much or carry it as far as a 77L, what it does is fly the route at significantly lower cost. It's a complex equation, simply saying the 77L might be able to generate more revenue isn't the full picture. DL appears to have decided that the difference isn't sufficient to warrant keeping the 77L fleet.

MIflyer12 wrote:

DL has had enough A350s for a while now (and had deferred some even before COVID-19 or the LATAM A350 commitments), and still chose to use 77Ls on the route. That suggests they value payload capability more than the A350's fuel savings.

Or it's simply being pre-Covid realistic - we have 77Ls in the fleets as well as A359s, so let's use the plane that's more expensive to operate on the routes where we get the most benefit (i.e. the longest, most challenging routes). However, when faced with a significant crunch, DL didn't value the 77L's payload capability enough to keep them.

Nobody's denying the 77L is a beast, but DL decided they couldn't justify continuing to operate it, preferring the lower operating costs of the A359 and simplifying the fleet.

scbriml wrote:

MIflyer12 wrote:

'It can fly it but without the payload' means it doesn't represent the same revenue opportunity. There's some value in being able to carry intercontinental freight, right?

Potential revenue is just that, potential.

While the A359 might not not be able to lift as much or carry it as far as a 77L, what it does is fly the route at significantly lower cost. It's a complex equation, simply saying the 77L might be able to generate more revenue isn't the full picture. DL appears to have decided that the difference isn't sufficient to warrant keeping the 77L fleet.

MIflyer12 wrote:

DL has had enough A350s for a while now (and had deferred some even before COVID-19 or the LATAM A350 commitments), and still chose to use 77Ls on the route. That suggests they value payload capability more than the A350's fuel savings.

Or it's simply being pre-Covid realistic - we have 77Ls in the fleets as well as A359s, so let's use the plane that's more expensive to operate on the routes where we get the most benefit (i.e. the longest, most challenging routes). However, when faced with a significant crunch, DL didn't value the 77L's payload capability enough to keep them.

Nobody's denying the 77L is a beast, but DL decided they couldn't justify continuing to operate it, preferring the lower operating costs of the A359 and simplifying the fleet.

Many have asserted that the A359 is as beastly as the 77L. The A359 can carry the same max payload as the 77L, but not as far.

Also, when adding payload, the more efficient plane has to give up more range. Or take less payload. Remove an hour of fuel, the 77L takes 7t more payload; whereas the A359 takes 5.8t more.

But the later weight variants closed the gap. Until now, where only the ATL - JNB nonstop had the latest A359s with insufficient payload. And it should be said that 6 out of 7 days, revenue potential was realized on ATL-JNB. So DL was loath to give up the revenue this flight generated. But DL also wanted to save money. So when the 278t and 280t became adequate on LAX-SYD and JFK-BOM (DL doesn't fly that many ULR routes), the CPT workaround was not enough of a disadvantage to keep the 77L fleet. Especially when promoting a captain to the 77L could cause 10 other pilot promotions and the respective retraining.

So DL did the workaround. And is saying goodbye to a fleet they just spent many millions refurbishing. They won't get a year use out of those D1 suites.

It's also worth noting (as at least one other poster has noted) that the A35J probably has enough MTOW to do JNB-ATL nonstop. Yet DL is doing the workaround with A359s. Clearly DL doesn't want another subfleet. So if the A359 can be made to work - and it can - DL takes the time hit. I say time because although the A359 has more seats than the 77L, it's not that much more. DL can't put on 100 more people at CPT . . .

A359 officially replaces 77L on LAX-SYD as of 1/1/21.

JFK-BOM and ATL-JNB still 77L for now.

https://www.routesonline.com/news/38/airlineroute/291681/delta-nw20-boeing-777-network-changes-as-of-07jun20/

Any idea why Delta is sending an A330-300 on the resumes ATL-LHR Route, and not a refurbished 767-400?

NateGreat wrote:

Any idea why Delta is sending an A330-300 on the resumes ATL-LHR Route, and not a refurbished 767-400?

Probably because they need the capacity given the social distancing requirements aboard the aircraft. Things may reshuffle in the event that they can ease social distancing, but at least through the end of the summer, they aren't going to go out over +/- 60% full.

TW870 wrote:

NateGreat wrote:

Any idea why Delta is sending an A330-300 on the resumes ATL-LHR Route, and not a refurbished 767-400?

Probably because they need the capacity given the social distancing requirements aboard the aircraft. Things may reshuffle in the event that they can ease social distancing, but at least through the end of the summer, they aren't going to go out over +/- 60% full.

IIRC LHR has some cargo contracts. With the 60%(its more like 57% once its averaged out cap we should be able to get roughly 30t of cargo on the A333. Assuming a DOW of around 126-128t and a 175t MZFW, "full" would be 167 pax, assume that as 16.7 tons, that'll give 31.3t of cargo.

TW870 wrote:

NateGreat wrote:

Any idea why Delta is sending an A330-300 on the resumes ATL-LHR Route, and not a refurbished 767-400?

Probably because they need the capacity given the social distancing requirements aboard the aircraft. Things may reshuffle in the event that they can ease social distancing, but at least through the end of the summer, they aren't going to go out over +/- 60% full.

Will the social distancing requirements be over by the October-December timeframe?

NateGreat wrote:

TW870 wrote:

NateGreat wrote:

Any idea why Delta is sending an A330-300 on the resumes ATL-LHR Route, and not a refurbished 767-400?

Probably because they need the capacity given the social distancing requirements aboard the aircraft. Things may reshuffle in the event that they can ease social distancing, but at least through the end of the summer, they aren't going to go out over +/- 60% full.

Will the social distancing requirements be over by the October-December timeframe?

Yes

Delta350 wrote:

NateGreat wrote:

TW870 wrote:

Probably because they need the capacity given the social distancing requirements aboard the aircraft. Things may reshuffle in the event that they can ease social distancing, but at least through the end of the summer, they aren't going to go out over +/- 60% full.

Will the social distancing requirements be over by the October-December timeframe?

Yes

How do you know? That’s the beginning of flu season, I imagine things could be even worse by then.

Jeremy

Delta Airlines A359 N514DN MSN 395 customer acceptance flight TLS-TLS (8 Jun)

AIB03GA msn395 caf 8/6/2020 by A380_TLS_A350, on Flickr

All B772ER going to fly with the recovery or some are retired already ?

danipawa wrote:

All B772ER going to fly with the recovery or some are retired already ?

There’s rumor they’ll keep the 77L

SESGDL wrote:

Delta350 wrote:

NateGreat wrote:

Will the social distancing requirements be over by the October-December timeframe?

Yes

How do you know? That’s the beginning of flu season, I imagine things could be even worse by then.

Jeremy

Lol right? This isn’t the thread to debate that, but one thing we can be certain on is there is no certainty. A flat “yes” is just wrong.

Delta350 wrote:

danipawa wrote:

All B772ER going to fly with the recovery or some are retired already ?

There’s rumor they’ll keep the 77L

I'm not sure who you heard the rumor from or when but Delta has already announced that it [entire B777 fleet] will be retired. It makes no sense for them to keep a very small fleet of 777L.

Delta announced A350-900 on ATL-JNB-ATL.

[url]https://www.routesonline.com/news/38/airlineroute/291812/delta-ns21-johannesburg-preliminary-schedule-filing-as-of-14jun20/
[/url]

'902

TWA902fly wrote:

Delta announced A350-900 on ATL-JNB-ATL.

[url]https://www.routesonline.com/news/38/airlineroute/291812/delta-ns21-johannesburg-preliminary-schedule-filing-as-of-14jun20/
[/url]

'902

https://www.routesonline.com/news/38/ai ... f-14jun20/

As it says though further changes will be made. Is that schedule the same as the current proposed NS20? In which case it most likely hasn't been updated for NS21.

359 cannot to ATLJNBATL, that is why Cape Town approval is being sought. Final routing will be ATLJNBCPTATL.