dw747400
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Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 12:39 pm

I was out at BWI today, and traffic was keeping the controllers very busy. A DL MD-80 was in position and holding, and was cleared on several occasions only to have its takeoff clearance revoked because it didn't get rolling fast enough.

After the third occurrence, the tower told him to clear the runway so the line of 737s behind him could get off. At this point he informed the tower that he needed 10 seconds to spool up his engines before beginning the takeoff roll because the temperature was just above freezing.

My question: why is this? No other aircraft seemed to have this issue, but this was the only DL flight, and only MD-80, I noticed. Thus, I'm guessing it is either DL operating procedures or something due to the MD-80's design (perhaps concern that ice off the fuselage could be ingested?) Anyone more informed than me on this one?
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XFSUgimpLB41X
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RE: Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 2:05 pm

He might have been deiced.... I know the DC-9's need to have a certain amount of seconds stabilized at takeoff power to clear the engines before they begin their takeoff roll if they have been deiced.

It was poor planning on their part not to let the tower know that they needed that amount of time at power, if that is the case.


...by the way.. its an MD-88.  Smile DL pilots will be quick to tell you its an 88 and not an 80, haha.
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dw747400
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RE: Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 2:58 pm

Quoting XFSUgimpLB41X (Reply 1):
He might have been deiced....

He most likely was. It was about 33-34 F out, with occasional snow and ice. Is the the power-up requirment due to the engine location?

Quoting XFSUgimpLB41X (Reply 1):
It was poor planning on their part not to let the tower know that they needed that amount of time at power

Yeah, they let him know after he told them to clear the runway. Sadly for the DL flight, tower had already decided what it wanted to see happen.

Quoting XFSUgimpLB41X (Reply 1):

...by the way.. its an MD-88.

Any major differences besides fuselage length in the MD80 series? I can never tell those suckers apart!
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vikkyvik
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RE: Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 3:52 pm

Quoting Dw747400 (Reply 2):
Any major differences besides fuselage length in the MD80 series? I can never tell those suckers apart!

Let's see if I can do this from memory:

MD-81/82/83/88 all have the same fuselage length

MD-87/Boeing 717 (MD-95) have a shorter fuselage

MD-90 has a longer fuselage

I think that covers it....

~Vik
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XFSUgimpLB41X
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RE: Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 5:05 pm

It has to do with clearing out the "vanes" from what I've been told. Which vanes, I don't know. I always assumed it had something to do with the bleeds. We used to have to do engine runups after deicing in the CRJ as well. Theres a decent likelihood Im going to be getting checked out on the 88 in the next few weeks... so I'll let you know once I learn (or 737 or 757/767- we shall see).

I personally can't tell the difference in the 80's... I just know the DL ones are 88's, haha. I'm sure I'll be able to if I get checked out on it.

[Edited 2007-02-03 09:06:42]
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Tristarsteve
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RE: Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 8:07 pm

After the MD80 accident at ARN many years ago, when ice was shed of the fan blades just after take off, SAS now run up the engines on the runway before releasing the brakes in icing conditions. They always tell the tower on first contact that they are going to do this.
 
XXXX10
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RE: Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 9:57 pm

Out of interest, would it have been possible to throttle up the engines before getting the take-off clearance, assuming the pilot could judge more or less when the clearance would come, by the height of the previous a/c?
 
miamiair
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RE: Takeoff In Cold Weather (DL MD80)

Sat Feb 03, 2007 10:16 pm

Quoting Dw747400 (Reply 2):
Any major differences besides fuselage length in the MD80 series? I can never tell those suckers apart!

MD-81 has MTOW of 140,000 pounds
MD-82, -88 has a MTOW of 149,500 pounds
MD-83 has a MTOW of 160,000(with 1,130 Gallon Aux Tank)
MD-87 has a MTOW of 140,000 pounds, with a shorter fuselage.
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RE: Takeoff In Cold Weather (DL MD80)

Sun Feb 04, 2007 12:17 am

Quoting TristarSteve (Reply 5):

No,it has nothing to do with the Gottrøra accident.That one was caused by ice breaking off the top surface of the wings and entering the engines.

The engine run-up on the MD after de/anti-icing is to clear the engines of any de/anti-icing fluids that might enter the the air cycle machines/air condtion system and create a grey mist or smoke that will come out of the air condition outlets in the cabin.10-15 seconds of thrust at 70% will do the job.LHR did positively NOT like this procedure and we usually did the run up on the taxiway,having first positioned the plane so as not to blow exhaust on planes behind us.Other types of engines/planes have probably different layouts in these systems and do not require this runup to my knowledge.
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vikkyvik
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RE: Takeoff In Cold Weather (DL MD80)

Sun Feb 04, 2007 2:09 am

Quoting Dw747400 (Reply 2):
Any major differences besides fuselage length in the MD80 series? I can never tell those suckers apart!



Quoting Vikkyvik (Reply 3):

I just noticed you said BESIDES fuselage length. D'oh!

Oh well. Good to test out the memory every now and then  Smile
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United_fan
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RE: Takeoff In Cold Weather (DL MD80)

Sun Feb 04, 2007 9:31 am

Quoting Dw747400 (Thread starter):
At this point he informed the tower that he needed 10 seconds to spool up his engines before beginning the takeoff roll because the temperature was just above freezing.

I heard the same request from a DL MD88 here in ROC last week,too.
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Fly2HMO
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RE: Takeoff In Cold Weather (DL MD80)

Sun Feb 04, 2007 1:35 pm

The engine's thrust rating (and model no. for that matter) does change slightly between -81/82/83 etc but externally there really is no way to differentiate amongst them (except for the -87, which is the shortest).
 
TrijetsRMissed
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RE: Takeoff In Cold Weather (DL MD80)

Sun Feb 04, 2007 1:50 pm

Quoting XFSUgimpLB41X (Reply 1):
...by the way.. its an MD-88. DL pilots will be quick to tell you its an 88 and not an 80, haha.

Yes the MD-88 is DL's plane. The airline had input in it's design. But for the record, they also operate a small fleet of MD-82's, and of course the MD-90's.

Quoting Dw747400 (Reply 2):
Any major differences besides fuselage length in the MD80 series?

Besides what has already been said, the big differences are the engines, the range, and the avionics.

The MD-82 quickly became the standard when it was introduced with more powerful engines than the original MD-81. The MD-83 and -87 have the best range,(-83 same capacity as an -82). The MD-88 is an improvement over the MD-82 with the JT8D-219 engines, refurbished cabin, and EFIS glass cockpit.

The MD-90 had much improved engines with the V2500 engines. Better range and fuel efficiency. They also provide the quietest cabin in the industry, because of the rear engine design.

The MD-90 also offers additional pax capacity, IFE, refurbished cabin, and avionic improvements.

Quoting Dw747400 (Reply 2):
I can never tell those suckers apart!

If you are unsure if you're spotting and MD-80 vs -90 at the airport, pay close attention to the engines while the aircraft lands. The the MD-80's have the distinctive clamp thrust reversers that fold over.
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MidEx216
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RE: Takeoff In Cold Weather (DL MD80)

Mon Feb 05, 2007 1:30 am

Quoting Dw747400 (Reply 2):
Any major differences besides fuselage length in the MD80 series?

The big thing that helps me tell them apart is that MD-80s have the cone on the tail, while the MD-88s have the dove-tail (where it tapers flat).
 
Fly2HMO
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RE: Takeoff In Cold Weather (DL MD80)

Mon Feb 05, 2007 3:00 am

Quoting MidEx216 (Reply 13):
The big thing that helps me tell them apart is that MD-80s have the cone on the tail, while the MD-88s have the dove-tail (where it tapers flat).

Its a pretty unreliable method. Some airlines have switched the tail cone on several models. AA is going for an all screwdriver-tail on their fleet IIRC.
 
TrijetsRMissed
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RE: Takeoff In Cold Weather (DL MD80)

Mon Feb 05, 2007 5:19 am

Quoting FLY2HMO (Reply 14):
Quoting MidEx216 (Reply 13):
The big thing that helps me tell them apart is that MD-80s have the cone on the tail, while the MD-88s have the dove-tail (where it tapers flat).

Its a pretty unreliable method. Some airlines have switched the tail cone on several models. AA is going for an all screwdriver-tail on their fleet IIRC.

Indeed. I think the best way of differeniating MD-82/83/88's is to know which carrier flies what. It's very hard to judge from the outside, especially from a distance. A lot of later models were built with the same tailcone.
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MidEx216
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RE: Takeoff In Cold Weather (DL MD80)

Mon Feb 05, 2007 3:18 pm

Quoting FLY2HMO (Reply 14):
Its a pretty unreliable method. Some airlines have switched the tail cone on several models. AA is going for an all screwdriver-tail on their fleet IIRC.

Oh, I did not know it was an option

Quoting TrijetsRMissed (Reply 15):
I think the best way of differeniating MD-82/83/88's is to know which carrier flies what

That's how I got that assumption - I always see the YX MD-80s, and the two -88s have the dove-tails, while all the others have the cones.

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