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LH A346 FRA-MLA FL100 ;)  
User currently offlineTS-IOR From Tunisia, joined Oct 2001, 3488 posts, RR: 6
Posted (1 year 5 months 3 weeks 4 days 11 hours ago) and read 3966 times:

http://fr24.com/DLH9924

It is clearly going to MLA for maintenance... but why staying at FL100 ? What failure or mechanical issue would force them to cruise such low ? Pressurisation ?!

20 replies: All unread, jump to last
 
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17055 posts, RR: 67
Reply 1, posted (1 year 5 months 3 weeks 4 days 11 hours ago) and read 3958 times:

Quoting TS-IOR (Thread starter):

http://fr24.com/DLH9924

It is clearly going to MLA for maintenance... but why staying at FL100 ? What failure or mechanical issue would force them to cruise such low ? Pressurisation ?!

That seems like a good candidate. Three engine ferry is another but seems unlikely. Besides I don't know if the 346 can do that.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinewilco737 From Greenland, joined Jun 2004, 9069 posts, RR: 76
Reply 2, posted (1 year 5 months 3 weeks 4 days 11 hours ago) and read 3946 times:
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Quoting TS-IOR (Thread starter):
What failure or mechanical issue would force them to cruise such low ? Pressurisation ?!

As said, these low altitudes are an indication for pressure issues. Ferry flight to Malta for maintenance.

Quoting Starlionblue (Reply 1):
Three engine ferry is another but seems unlikely. Besides I don't know if the 346 can do that.

I guess it is possible, but the other question: is it allowed? And in HAM maintenance should be good enough equipped to perform an engine change instead of flying ferry to Malta.

wilco737
  

[Edited 2013-04-09 01:08:50]


It it's not Boeing, I am not going.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17055 posts, RR: 67
Reply 3, posted (1 year 5 months 3 weeks 4 days 10 hours ago) and read 3923 times:

Quoting wilco737 (Reply 2):
Quoting Starlionblue (Reply 1):
Three engine ferry is another but seems unlikely. Besides I don't know if the 346 can do that.

I guess it is possible, but the other question: is it allowed? And in HAM maintenance should be good enough equipped to perform an engine change instead of flying ferry to Malta.

Yes but think of the fun to be had doing it. 

Seriously though, I didn't think it was a strong possibility.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinewilco737 From Greenland, joined Jun 2004, 9069 posts, RR: 76
Reply 4, posted (1 year 5 months 3 weeks 4 days 10 hours ago) and read 3908 times:
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Quoting Starlionblue (Reply 3):
Yes but think of the fun to be had doing it

To be honest, I don't want to fly in the lower airspace for so long... All the VFR traffic, birds etc. I prefer flying higher. But it is for sure a nice sightseeing tour 
Quoting Starlionblue (Reply 3):
Seriously though, I didn't think it was a strong possibility.

I guess it is something which can easier be fixed in Malta. Or a check was due anyway and they plan to repair all at the same time in Malta.

wilco737
  



It it's not Boeing, I am not going.
User currently offlineAC_B777 From Canada, joined Aug 2000, 809 posts, RR: 13
Reply 5, posted (1 year 5 months 3 weeks 4 days 7 hours ago) and read 3806 times:

We recently had an A320 with a damaged L1 door that had to do a ferry flt from YYT-YUL. Because the a/c could not be pressurized, it had to stay at or below FL100.
From my understanding, the flight took about 4 hours instead of the normal 2-2.5 hours to reach YUL and burned a hell of a lot more fuel due to the lower altitude.



In life, some days you are the bug..... some days you are the windshield!
User currently offlinewilco737 From Greenland, joined Jun 2004, 9069 posts, RR: 76
Reply 6, posted (1 year 5 months 3 weeks 4 days 6 hours ago) and read 3786 times:
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Quoting AC_B777 (Reply 5):
and burned a hell of a lot more fuel due to the lower altitude.

Oh yeah, that's for sure. Better not think about how much... It is siginficantly more.

wilco737
  



It it's not Boeing, I am not going.
User currently offlineAesma From France, joined Nov 2009, 6690 posts, RR: 12
Reply 7, posted (1 year 5 months 3 weeks 4 days 3 hours ago) and read 3692 times:

About a three engines ferry, I doubt it would be wise and I don't see a valid reason to do it, it would be similar to a one engine ferry of a twin, and we know that doesn't happen, even if the alternative means flying a GE90 to Greenland.


New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
User currently offlineB777LRF From Luxembourg, joined Nov 2008, 1368 posts, RR: 3
Reply 8, posted (1 year 5 months 3 weeks 4 days 1 hour ago) and read 3616 times:

[quote=Aesma,reply=7]About a three engines ferry, I doubt it would be wise and I don't see a valid reason to do it, it would be similar to a one engine ferry of a twin, and we know that doesn't happen, even if the alternative means flying a GE90 to Greenland./quote[

Strange that, as simple math would seem to suggest loosing one engine on a twin eguals a loss of 50% and no back-up, whereas the loss of one on a quad equals a loss of only 25% and still having two to play with in case one more should go pop.

3-engined ferries are done, if not regularly, then often enough to make them regular occurrences. And it's a lot cheaper to fly 'er home on 3, rather than having to charter a 747 to deliver an engine, spares, tools and mechanics to the back of beyond.



From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
User currently offlineSemaex From Germany, joined Nov 2009, 823 posts, RR: 2
Reply 9, posted (1 year 5 months 3 weeks 3 days 22 hours ago) and read 3548 times:

Quoting B777LRF (Reply 8):
Strange that, as simple math would seem to suggest loosing one engine on a twin eguals a loss of 50% and no back-up, whereas the loss of one on a quad equals a loss of only 25% and still having two to play with in case one more should go pop.

Careful with that sort of calculation.
A loss of one engine on a twin usually means a performance reduction of about 80%, because due to the asymetric moments and the forces of the flight surfaces to counter those, a lot of drag is being generated that reduce performance quite drastically, especially with the critical engine dead.
On a quad a loss of one engine doesn't affect performance by 25% either, it will be more. But the effects aren't as pronounced as on a twin of course.

Having said that, I don't actually know what you mean by "a loss of 50%" ^^


Question on topic: They couldn't have cruised all the way to Malta at FL100 right? I mean, in the Austrian Alps you have MSAs of 11000 or more, Switzerland even higher... ?!



// You know you're an aviation enthusiast when you look at your neighbour's cars and think about fleet commonality.
User currently offlinewilco737 From Greenland, joined Jun 2004, 9069 posts, RR: 76
Reply 10, posted (1 year 5 months 3 weeks 3 days 22 hours ago) and read 3529 times:
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Quoting Semaex (Reply 9):
Question on topic: They couldn't have cruised all the way to Malta at FL100 right? I mean, in the Austrian Alps you have MSAs of 11000 or more, Switzerland even higher... ?!

Correct, you cannot fly above the Alps at 10.000 feet. You can reply the flight track and then you can see that they departed southwest towards france, then directly south. Staying west of the alps, towards Marseille and then onto water. And from there on, no big deal. So huge detour, flying at 10.000 feet all the time: lots of fuel...

wilco737
  



It it's not Boeing, I am not going.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17055 posts, RR: 67
Reply 11, posted (1 year 5 months 3 weeks 3 days 19 hours ago) and read 3457 times:

Quoting Aesma (Reply 7):
About a three engines ferry, I doubt it would be wise and I don't see a valid reason to do it, it would be similar to a one engine ferry of a twin, and we know that doesn't happen, even if the alternative means flying a GE90 to Greenland.

It would not be similar since if you lost an engine you would still have two engines.

Quoting B777LRF (Reply 8):
3-engined ferries are done, if not regularly, then often enough to make them regular occurrences. And it's a lot cheaper to fly 'er home on 3, rather than having to charter a 747 to deliver an engine, spares, tools and mechanics to the back of beyond.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineRara From Germany, joined Jan 2007, 2093 posts, RR: 2
Reply 12, posted (1 year 5 months 3 weeks 3 days 19 hours ago) and read 3444 times:

Quoting Starlionblue (Reply 11):
It would not be similar since if you lost an engine you would still have two engines.

But are two engines enough to get a quad safely in the air? Twins are rated and certified for the loss of one engine, and so are quads. But loss of two engines at Vr? I don't think this is part of any realistic scenario.

Three-engine ferries must operate on a no-failure-tolerance basis then.



Samson was a biblical tough guy, but his dad Samsonite was even more of a hard case.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17055 posts, RR: 67
Reply 13, posted (1 year 5 months 3 weeks 3 days 18 hours ago) and read 3422 times:

Quoting Rara (Reply 12):
But are two engines enough to get a quad safely in the air? Twins are rated and certified for the loss of one engine, and so are quads. But loss of two engines at Vr? I don't think this is part of any realistic scenario.

Three-engine ferries must operate on a no-failure-tolerance basis then.

Quads are certified for the loss of one engine while taking off at MTOW. On a ferry flight the plane would be empty apart from fuel and flight crew. The weight would be far less than MTOW, especially on a long range airliner like a 747. Operating Empty Weight for a 747-400 is around 400,000lb and MTOW is for most variants is well north of 800,000lb. Granted you'd be using a chunk of that for fuel but methinks you'd still have excess power.

AFAIK a 747 or other quad can climb on two engines if it is light. I don't have the math though, and certainly the scenario where the "off" engine (on the already half dead side) quits at V1 sounds hairy.


While we are on the subject I think I remember someone posting about two engine ferrying a Tristar...

[Edited 2013-04-09 18:27:20]


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinewilco737 From Greenland, joined Jun 2004, 9069 posts, RR: 76
Reply 14, posted (1 year 5 months 3 weeks 3 days 13 hours ago) and read 3338 times:
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Quoting Rara (Reply 12):
But are two engines enough to get a quad safely in the air?
Quoting Rara (Reply 12):
But loss of two engines at Vr? I don't think this is part of any realistic scenario.

Well, chances aren't good if you have a double engine failure on a 4 engine airplane at high weight. At low weight (ferry flight) I assume it is possible to bring it into the air or 3 engine ferry flights wouldn't be allowed at all. Just don't hit full thrust right away as it could weer you off the runway as the rudder is not effective at low speeds and you cannot keep the airplane on the runway with that amount of assymetrical thrust.

Quoting Starlionblue (Reply 13):
Granted you'd be using a chunk of that for fuel but methinks you'd still have excess power.

Exactly. I did a 2 engine go around on the 744 in the simulator. We had a normal landing weight. it was not great, but it worked and a little climb performance is possible as well.

Quoting Starlionblue (Reply 13):
AFAIK a 747 or other quad can climb on two engines if it is light.

Yes, it can. But as you said at light or medium weight. As said: 2 engine go around is possible up to a certain weight.

Quoting Starlionblue (Reply 13):
While we are on the subject I think I remember someone posting about two engine ferrying a Tristar...

Yes, it has been done on the MD11 as well IIRC. But they hit full throttle on take off and the airplane turned on the spot...

wilco737
  



It it's not Boeing, I am not going.
User currently offlineAesma From France, joined Nov 2009, 6690 posts, RR: 12
Reply 15, posted (1 year 5 months 3 weeks 3 days 6 hours ago) and read 3235 times:

I was guessing that it was not done because while twins are certified and tested extensively on one engine, quads aren't on two engines. Does the rudder have enough authority if you're left with two engines on one side ?

If we take the A343, an interesting case since it's an A333 with 4 smaller engines. The A333 engines are situated where the inboard engines on the A343 are. So if you lose two engines on the same wing on the quad, your remaining thrust comes from further away on the wing. Can it fly ? Even Concorde with its engines far less apart ended up inverted on two engines.

I seem to remember a 747 and also a 707 crashed after losing two engines.



New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
User currently offlinewilco737 From Greenland, joined Jun 2004, 9069 posts, RR: 76
Reply 16, posted (1 year 5 months 3 weeks 3 days 6 hours ago) and read 3230 times:
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Quoting Aesma (Reply 15):
Does the rudder have enough authority if you're left with two engines on one side ?

During a two engine out condition during cruise, yes the rudder has enough authority. You can fly a two engine out approach easily. No big deal in the 744. Even in the MD11 I have done it (requirement by law to do that in your checkrides in the simulator).
Only the two engine go around you cannot advance to full thrust if you have 2 engines out at the same side. Then the yaw momentum is too big to be covered by the rudder. You need to speed up slowly and then the effectiveness increases of the rudder and you are safe.

wilco737
  



It it's not Boeing, I am not going.
User currently offlineLH707330 From United States of America, joined Jun 2012, 788 posts, RR: 0
Reply 17, posted (1 year 5 months 3 weeks 3 days 1 hour ago) and read 3124 times:

Quoting Aesma (Reply 15):
I seem to remember a 747 and also a 707 crashed after losing two engines.

If you're referring to the El Al crash in Amsterdam in 1992, that one happened because the #4 engine took out the outboard flaps, which led to asymmetrical lift that the ailerons couldn't compensate at lower speeds. There was an E-3 (707 AWACS) crash in Alaska from a dual birdstrike in #1 and #2, they got the nightmare scenario of the birds right after rotation and didn't have much rudder or aileron authority.


User currently offlinejagflyer From Canada, joined Aug 2004, 3537 posts, RR: 4
Reply 18, posted (1 year 5 months 3 weeks 2 days 2 hours ago) and read 2907 times:

Why MLA of all places? You would think LH Technik in FRA, MUC or HAM would be able to perform any maintenance that would be possible in Malta. I don't associate Malta with 3rd party aircraft maintenance...

EDIT: It seems Malta does have an LH Technik facility..interesting



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User currently offlinezeke From Hong Kong, joined Dec 2006, 9113 posts, RR: 75
Reply 19, posted (1 year 5 months 3 weeks 2 days 1 hour ago) and read 2892 times:

Quoting Starlionblue (Reply 1):

A OEI ferry would see an A346 above FL300, FL100 I would guess to be a structural problem, door, tail scrape etc.

Quoting wilco737 (Reply 2):

OEI ferry is a standard published procedure in FCOM 2, so is a depress ferry.

Quoting Rara (Reply 12):

The A340 can fly with 3 engines out, and unlike the 747, th APU can be started in air like the A330. It is no something that can be done at all weights, however it is possible.

Quoting Aesma (Reply 15):

Quads are tested with two engines out, something we do in the sim on a regular basis.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently online7BOEING7 From United States of America, joined Oct 2012, 1601 posts, RR: 8
Reply 20, posted (1 year 5 months 3 weeks 1 day 23 hours ago) and read 2866 times:

Many years ago the Boeing Company had contracts with various airlines to perform 3 engine ferries on 747's and 2 engine ferries on 727's. As opposed to the photo in Reply 11, the engines were still on the wing. The airplanes were flown at a very light weight. Several 747's were flown from New York to London. Flying with one or two engines out in a quad is not a big issue depending on the weight, however, taking off with an outbd engine out even at light weights is tricky. There is no comparison between losing an engine at V1 and trying to take off with one already dead. You need a long runway and a skilled crew. In the late 80's with fewer and fewer engine out flights being done, Boeing ceased providing the service.

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