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1337Delta764
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DL Vs. AA At Hot-and-high Airports

Fri May 22, 2009 5:33 pm

Don't be deceived by the title. This is not a poll.

I was wondering, why do DL and AA have two completely different strategies when it comes to hot-and-high airports? DL generally tries to avoid using the MD-88 into hot-and-high airports during the summer months. AA, on the other hand, doesn't seem to have any issues with it, as the majority of hot-and-high cities with AA are served with MD-80s.

Is there any particular reason why hot-and-high conditions are an important issue for DL but not for AA? Here at ABQ, DL mostly uses the 752 here during the summer months, with the MD-88 mostly only used during the cooler early morning ABQ-ATL flights. AA, on the other hand, uses (or will be using after ABQ-ORD goes mainline next month) the MD-80 out of ABQ exclusively. I am quite surprised AA isn't changing the ABQ-ORD flight to a 738, as AA has re-introduced 738 flying at ORD.
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vikkyvik
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RE: DL Vs. AA At Hot-and-high Airports

Fri May 22, 2009 6:23 pm



Quoting 1337Delta764 (Thread starter):
Is there any particular reason why hot-and-high conditions are an important issue for DL but not for AA? Here at ABQ, DL mostly uses the 752 here during the summer months, with the MD-88 mostly only used during the cooler early morning ABQ-ATL flights. AA, on the other hand, uses (or will be using after ABQ-ORD goes mainline next month) the MD-80 out of ABQ exclusively. I am quite surprised AA isn't changing the ABQ-ORD flight to a 738, as AA has re-introduced 738 flying at ORD.

Just out of curiousity, are you sure the aircraft change for DL in the summer is due to local weather? Could it be due to passenger increase during the summer months, as a 752 can hold significantly more than an MD-80?

Other than that, you'd have to look at whether DL is flying longer flights than AA with their MD-80s. Also whether they both have the same engines and MTOWs, how many passengers they're configured for, whether they're carrying cargo, etc, etc....

Chances are everything is not equal on these flights, even though they're using the same aircraft. And that makes it hard to compare.
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KELPkid
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RE: DL Vs. AA At Hot-and-high Airports

Fri May 22, 2009 6:57 pm

AA doesn't seem to have any issues at ELP, and for that matter, neither does DL  Smile

I have seen, and been on, summer departures for DFW, ORD, and ATL on Maddogs for both carriers on 100+ degree days.

ELP has a field elevation of 3956, and no cargo or pax were offloaded on any of the flights I have been on...

Although I'm not sure if DL sometimes uses the MD-90 on ELP-ATL in summer (I wasn't spotter-savvy enough back then to know the difference between an MD-88, or an MD-90 back then, nor did I really care back then  blush  ). However, the DL flight didn't go out anywhere near full, either...(I'd guess 65-70% LF).

It is also interesting to note that the airliners aren't immune to a local phenomenon my instructor called "the whooptas." Basically, when a nice huge dark surface heats up (like a mall parking lot, or a brown farmer's field, for instance), you get bounced around a lot in a GA plane, and summertime flying after about 10AM can be a miserable experience down low in that part of the world due to this...  vomit  Although it's not nearly as bad in a heavier plane  Smile
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1337Delta764
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RE: DL Vs. AA At Hot-and-high Airports

Fri May 22, 2009 7:15 pm



Quoting Vikkyvik (Reply 1):
Just out of curiousity, are you sure the aircraft change for DL in the summer is due to local weather? Could it be due to passenger increase during the summer months, as a 752 can hold significantly more than an MD-80?

Well, I know for a fact that DL has had issues with using the MD-88 on ABQ-ATL/CVG in the summers of 2006 and 2007. This year, they are only used on the 6:25 AM ABQ-ATL flight, probably because it is much cooler in ABQ during that time of day. The other two flights are mostly 752s, with an occasional 738.

Quoting Vikkyvik (Reply 1):
Other than that, you'd have to look at whether DL is flying longer flights than AA with their MD-80s. Also whether they both have the same engines and MTOWs, how many passengers they're configured for, whether they're carrying cargo, etc, etc....

As far as I know, DL's MD-88s have the same MTOW as AA's MD-82s. Of course, AA also operates the MD-83 (which has a higher MTOW), however, they usually don't fly them into ABQ.

Quoting KELPkid (Reply 2):
Although I'm not sure if DL sometimes uses the MD-90 on ELP-ATL in summer (I wasn't spotter-savvy enough back then to know the difference between an MD-88, or an MD-90 back then, nor did I really care back then ). However, the DL flight didn't go out anywhere near full, either...(I'd guess 65-70% LF).

From what I have heard, during the summer of 2008, DL had 90-95% LF on the ABQ-ATL flights, which all three were flown by 752s. I don't know what AA has on their ABQ-ORD flight, unfortunately.
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Viscount724
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RE: DL Vs. AA At Hot-and-high Airports

Fri May 22, 2009 9:15 pm



Quoting Vikkyvik (Reply 1):
Other than that, you'd have to look at whether DL is flying longer flights than AA with their MD-80s. Also whether they both have the same engines and MTOWs, how many passengers they're configured for, whether they're carrying cargo, etc, etc....

I believe AA's MD-82s use the JT8D-217C engine while DL's MD-88s (and AA's MD-83s) use the JT8D-219 which, if not mistaken, has about 1,000 lbs. more thrust than the -217C.

According to the FAA type certificate data sheet, the -219 only also has a special higher thrust rating for hot/high operations that adds another 700 lbs. of thrust. Excerpt from the relevant note in the FAA type certificate:

A thrust setting is limited to 21,700 lbs. static thrust at sea level, flat rated to 90.4°F ambient temperature has been established as auxiliary maximum takeoff for the JT8D-219 engine model. The auxiliary maximum takeoff setting provides additional hot day performance on the JT8D-219 engine model only and is achieved by manual setting of the power lever only, with the automatic reset mechanism disarmed (off).

The part life accounting procedure is the same as for the maximum takeoff rating except that a two for one cycle penalty must be applied to the sixth stage compressor disk whenever the auxiliary maximum takeoff rating is applied.
 
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1337Delta764
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RE: DL Vs. AA At Hot-and-high Airports

Fri May 22, 2009 10:55 pm

Keep in mind that in the summer of 2006, DL operated ABQ-ATL with 4x MD-88. There probably is a reason why DL is no longer doing this, and most likely it is because of the hot-and-high issues that the MD-88 has in the summer out of ABQ.

Interestingly, prior to late 2005, DL normally didn't operate any MD-88s at ABQ; most flights to ATL and CVG were either on 752s or 738s. ABQ used to also get many 722s before they were retired in 2003 (I flown on one in 2001 when my family moved into the Albuquerque area).
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Transpac787
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RE: DL Vs. AA At Hot-and-high Airports

Sat May 23, 2009 1:38 pm



Quoting 1337Delta764 (Thread starter):
AA, on the other hand, doesn't seem to have any issues with it, as the majority of hot-and-high cities with AA are served with MD-80s.

Not completely true.

Given how AA has nearly 300 Super 80's and will operate them for some time to come, they've done just about every cost, fuel, and weight saving modification to them one can do. So, it's quite possible they do, indeed, have better performance than the DL models. However, I know first hand that out of DEN, the Supers will take weight limits in the peak heat of July. This is why, for the summer schedule, AA has made DEN-LAX 2x 738 and has put 738's on two of the four daily DEN-ORD flights... the afternoon ones, IIRC, while the morning and evening flights remain as S80's.

Quoting Viscount724 (Reply 4):
I believe AA's MD-82s use the JT8D-217C engine while DL's MD-88s (and AA's MD-83s) use the JT8D-219 which, if not mistaken, has about 1,000 lbs. more thrust than the -217C.

The AA MD-82's used to have the -217C's, true enough, but have all since been retrofitted by AA to have the -219's.
 
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RE: DL Vs. AA At Hot-and-high Airports

Sat May 23, 2009 5:00 pm



Quoting Transpac787 (Reply 6):
This is why, for the summer schedule, AA has made DEN-LAX 2x 738 and has put 738's on two of the four daily DEN-ORD flights... the afternoon ones, IIRC, while the morning and evening flights remain as S80's.

Well, comparing ABQ to DEN, DEN is only slightly higher in elevation, however, it gets much hotter in ABQ during the summer months as ABQ is further south. So, why would AA use the 738 at DEN but not at ABQ?
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josekmlb
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RE: DL Vs. AA At Hot-and-high Airports

Mon May 25, 2009 9:18 pm

I just checked DL term threw JUNE and ATL-ABQ have 3 flights which 2 are 757s and 1 MD-88
but looks like in sept. they will all be MD-88s

AA for ABQ-ORD are flying CR7s and MD-80s in JUNE.
 
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RE: DL Vs. AA At Hot-and-high Airports

Tue May 26, 2009 5:24 pm



Quoting JoseKMLB (Reply 8):
I just checked DL term threw JUNE and ATL-ABQ have 3 flights which 2 are 757s and 1 MD-88
but looks like in sept. they will all be MD-88s

Well, if you check the time that the MD-88 flight leaves out of ABQ, it is a 6:25 AM where it is significantly cooler than in the afternoon.

Also, around late August/early September is generally when the heat dissipates and when demand falls, so it is not surprising that all flights will be MD-88s in September. There is a slight increase in demand in October due to the Albuquerque Balloon Fiesta; DL had one 752 on ATL-ABQ daily in October of last year. However, demand falls again in November and generally doesn't pick up until March of the next year.
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FlyASAGuy2005
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RE: DL Vs. AA At Hot-and-high Airports

Tue May 26, 2009 6:01 pm

Just from my personal observation of this industry and how different airlines does business. It may just boil down to philosophy on how they choose to operate. Much like Airbus and Boeing. Both have excellent products yet when it comes down to their systems, etc. very different approaches to how the a/c should operate and pilot interface. Two different philosophies but from what i've heard from pilots that's flown both, none right or wrong.

Same thing I think.
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deltal1011man
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RE: DL Vs. AA At Hot-and-high Airports

Sun May 31, 2009 6:14 am



Quoting 1337Delta764 (Reply 3):
Well, I know for a fact that DL has had issues with using the MD-88 on ABQ-ATL/CVG in the summers of 2006 and 2007. This year, they are only used on the 6:25 AM ABQ-ATL flight, probably because it is much cooler in ABQ during that time of day. The other two flights are mostly 752s, with an occasional 738.

It has to due with heat in both Atlanta and ABQ and the hight in ABQ. ATL-ABQ is also longer than ORD.
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