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Spangly
16th Apr 2008, 23:03
Speaking as a curious air traffic controller….a 747-400 departed from Stansted today with one winglet missing (they were aware of it). I was wondering what difference this would make to the flying qualities?

- would there be any noticeable difference in the handling?
- would any of the speeds or procedures change?

I guess there would be some difference in fuel used, but enough to warrant extra being taken on for reserves?

Thanks.

tubby linton
16th Apr 2008, 23:16
It used to be an rtow reduction of almost 20t! on the A330!

Sand Man
17th Apr 2008, 01:07
Someone correct me if I'm wrong but you can fly a 747-400 with one winglet missing but not both, why?
I have also heard that you can buy 747-400's without winglet? Is there a difference in the wing design or am I missing something?

OutOfRunWay
17th Apr 2008, 08:14
The short-range 747-400 such as the ones used on japanese domestic routes have no winglets and are also constructed for more cycles.

OORW

Mac74
17th Apr 2008, 17:47
There is a penalty on performance of almost 10t for take off. And a fuel increase of 2,5%.
But no speed restrictions/differences with a missing winglet.

Mac74

boofhead
17th Apr 2008, 18:25
You would think that if the winglet has some effect on drag, it would be noticeable to the pilot when flying with one removed, ie some evidence of yaw, instability on approach or takeoff etc. But apparently not, and one flight I saw with a missing winglet (London to Singapore) actually burned less than flight-planned fuel. And the MEL allows flight with only one?
Made me wonder if the winglet (at least on the 744) was worth the effort.

XPMorten
17th Apr 2008, 19:14
Someone correct me if I'm wrong but you can fly a 747-400 with one winglet missing but not both, why?

Think the reason you can only fly with one missing is that Boeing
didn't certify it for flying with two missing. Not because it can't,
but because the process is expensive and the chances of two winglets
missing at once is minor.

M

Sand Man
18th Apr 2008, 01:30
Thanks for the answer. I should have realized that it all comes down to money and not actually have anything to do with aircraft safety.

kick the tires
18th Apr 2008, 02:32
Sand man,

what a strange sarcastic reply.

The post above explains so whats the issue??

CV880
18th Apr 2008, 04:08
During flight testing the manufacturer tests the aircraft with every access door, fairing, etc, etc that they figure will be knocked off by accident or fall off due undetected wear and tear or as a result of not being closed or secured properly and puts all the data in the Configuration Deviation List (CDL) which is an appendix to the Flight Manual.
It is very expensive and time consuming to go back and redo a test for some bit that gets knocked off that nobody thought of first time round. It can be done whilst testing a variant of the same model and possibly the data can be read back to previous versions.
The Japanese -400SR's were certified without winglets and are a unique variant of the 747-400.
As someone wrote above Boeing no doubt figured you would only damage one winglet at a time

Spangly
19th Apr 2008, 14:56
Thanks for all the info, useful to know.