An225
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B757-300 Operations From Short Desert Runways

Tue Aug 16, 2011 12:27 pm

Hello all,
Arkia Israel Airlines is operating its 757-300 equipment on the route TLV-ETH sometimes fully packed with tourists (around 260 pax per flight). This is a rather short route, ~500 km. Not much fuel is needed and no cargo is taken.
Looking at the Israeli AIP, ETH runway length is 1,900 m'.
Looking at Boeing's technical data, MTOW on standard day + 14C you need a 2,900 m' runway if you operate on 270,000lbs at sea level. If you want to take off and not end up in Eilat bay (or the sewage facilities/algae plantation) you need to reduce weight to 230,000lbs. If you take off on a very hot day (above 40C) the MTOW will be probably reduced to around 208,000lbs.
Looking again at Boeing's technical data, MZFW on 0-500 nautical miles route must be 210,000lbs.

I wonder how they are able to load a 260 pax with all their luggage (believe me they have plenty) and still take-off with such limitations. Comments anyone?

Thanks

An225
 
tb727
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RE: B757-300 Operations From Short Desert Runways

Tue Aug 16, 2011 2:44 pm

Quoting An225 (Thread starter):
I wonder how they are able to load a 260 pax with all their luggage (believe me they have plenty) and still take-off with such limitations. Comments anyone?

You already kinda answered it, If they are really going with a full load of pax, then they are leaving fuel off. You are either leaving people or fuel behind to make a certain weight for the runway and that weight changes throughout the day with conditions such as wind and temperature changes. That being said, it's hard to say without looking at the airlines performance data for this specific flight and their airplanes, the Boeing data is pretty general.
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Stitch
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RE: B757-300 Operations From Short Desert Runways

Tue Aug 16, 2011 3:37 pm

Quoting An225 (Thread starter):
I wonder how they are able to load a 260 pax with all their luggage (believe me they have plenty) and still take-off with such limitations. Comments anyone?

Pax and bags alone should not get the plane to MZFW so even loading fuel they may still be below MZFW and therefore within the TOW necessary for field performance.
 
Max Q
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RE: B757-300 Operations From Short Desert Runways

Wed Aug 17, 2011 5:19 am

Where / what is ETH ?
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Starlionblue
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RE: B757-300 Operations From Short Desert Runways

Wed Aug 17, 2011 1:03 pm

Quoting Max Q (Reply 3):
Where / what is ETH ?

Eilat Airport in Israel. ICAO code LLET.
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rfields5421
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RE: B757-300 Operations From Short Desert Runways

Wed Aug 17, 2011 1:53 pm

Quoting Max Q (Reply 3):
Where / what is ETH ?

At the very southern tip of Israel on the Red Sea coast. A very tight airspace with Aqaba Jordan airport, AQJ, about 3 nm away, the Jordan border less than a mile away. Egypt is about 4 nm the other way with Taba, TCP, about 8 nm away.
 
n685fe
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RE: B757-300 Operations From Short Desert Runways

Thu Aug 18, 2011 11:33 pm

Quoting rfields5421 (Reply 5):
At the very southern tip of Israel on the Red Sea coast. A very tight airspace with Aqaba Jordan airport, AQJ, about 3 nm away, the Jordan border less than a mile away. Egypt is about 4 nm the other way with Taba, TCP, about 8 nm away.

So in a situation like this, do the three nations allow airlines to over fly a neighboring nation to allow the a/c to line up? Is the Red Sea considered international air space being that close to three nations? Just wondering what the ops procedures are for such a tight air space.
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fly707
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RE: B757-300 Operations From Short Desert Runways

Thu Sep 29, 2011 11:44 am

Quoting N685FE (Reply 6):
So in a situation like this, do the three nations allow airlines to over fly a neighboring nation to allow the a/c to line up? Is the Red Sea considered international air space being that close to three nations? Just wondering what the ops procedures are for such a tight air space.

Yes you can fly between the three airports normally.
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Fabo
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RE: B757-300 Operations From Short Desert Runways

Fri Sep 30, 2011 11:56 am

I just looked up ETH in Google Maps. Wow, I don't think I ever saw such a tightly packed airport.

That said, let's take a look at what actually is the basis for take-off calculations.

There are basically two limits you have to cram into - climb performance requirements and runway lenght-related performance.

As you have noted, Eilat has sea on one side, and what looks like pretty much flat desert on the other side, what means, you don't really have to limit yourself by climb. Which is lucky, since you can trade climb performance for runway performance via use of higher flap settings, IIRC, a 757 will allow pretty much any position between 1 and 20 degrees.
On longer, but climb-limited runways, you would want to use the smallest possible flap setting, and then trade runway for climb rate, here you are doing it the other way.

I don't have performance data for a 757-300 though, so I can't relly help you with specific numbers. I could do 752, but I guess that wouldn't be much help.

(I realize you probably know this, but Tech Ops section is a great place to learn, and I would have been glad to have found a little insight - hopefully, I did not put any errors in.)
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mandala499
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RE: B757-300 Operations From Short Desert Runways

Fri Sep 30, 2011 8:57 pm

Quoting Fabo (Reply 8):
As you have noted, Eilat has sea on one side, and what looks like pretty much flat desert on the other side, what means, you don't really have to limit yourself by climb. Which is lucky, since you can trade climb performance for runway performance via use of higher flap settings, IIRC, a 757 will allow pretty much any position between 1 and 20 degrees.
On longer, but climb-limited runways, you would want to use the smallest possible flap setting, and then trade runway for climb rate, here you are doing it the other way.

Well, it's not flat in terms of obstacles unfortunately.

Looks nice and flat here...

View Large View Medium
Click here for bigger photo!

Photo © Ronen Eckstein



But... departing 03...

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Photo © Yoni67


Nice little terrain immediately, and threshold 03 is 16', while 21 is 43', slope of 0.5%... and minimum climb gradient required is 6.2%

And then.. looking at what's just south of threshold 03....

View Large View Medium
Click here for bigger photo!

Photo © Ronen Eckstein


Take off 21 require 6.5%...

And the actual threshold to threshold length is only 1612 meters...

Makes for some nice take-off calculations    But am sure the 752 would find such a situation a doddle... 753... dunno...

Mandala499
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Cubsrule
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RE: B757-300 Operations From Short Desert Runways

Fri Sep 30, 2011 9:10 pm

Quoting mandala499 (Reply 9):
But am sure the 752 would find such a situation a doddle... 753... dunno...

I don't have the numbers in front of me, but my experience as a passenger is that when the 752/753 are light (short routes and/or less than full airplanes), the runway performance isn't much different. FWIW, I think the same is true with some other families as well (I've been on WN flights on both 733s and 73Gs with really light loads and both rocket off the airport).
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Fabo
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RE: B757-300 Operations From Short Desert Runways

Fri Sep 30, 2011 9:16 pm

Quoting mandala499 (Reply 9):

Ooops, looks like my runway data is incomplete in Israel. Note to self: try and get data.
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mandala499
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RE: B757-300 Operations From Short Desert Runways

Sat Oct 01, 2011 11:10 pm

Quoting Fabo (Reply 11):
Ooops

Don't worry... I just happen to remember seeing the photo of the ATR42 flight deck shot on approach, then decided to look at the charts...   
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