B777-200/B777-200ER Manufacturer's Empty Weight (MEW)

[Hydrogen Alpha]

Hi,

I'd really appreciate some help here - I'm struggling badly.

I am trying to get a good figure for the typical MEW for a B777-200 & B777-200ER (say Pratt power as a datum, accepting that Rolls are lighter and GE heavier), but the data sources I have - and definitions of MEW - just don't reconcile.

To be as brief as I can;

- Both Airbus' & Boeing's MEW definitions appear to be identical - "structure, powerplant, systems, furnishings and other items that are an integral part of the aircraft configuration, including fuilds contained in closed systems" - and Operator Items are excluded.

- Despite the reference to "furnishings", Airbus confirm to me that they regard seats as Operator Items, and not part of the MEW (which must be logical).

- However, the Boeing position on seats (from published and proprietary data) appears to be ambiguous. Not clear at all whether they are "in" or "out" of the MEW.

- In terms of actual weights, Boeing's now ancient B777 ACAP from 1998 shows an "illustrative" OEW for the 777-200ER of 304,500 lbs, while a United Airlines W&B shows the MEW for the same aircraft type as 281,575 lbs - apparently BEFORE the weight of seats are deducted, implying a net MEW, without seats, of about 260,000 lbs.

- So where's the problem? The problem is that airframe-specific W&B Booklets I have for two airline's B777-200ER fleets show
average fleet OEWs of 328,591 lbs and 322,292 lbs respectively, way above the ACAP fugure, which point to "Basic Empty Weights", without seats, of around 285,000 lbs - 25,000 lbs above the figure implied from the UA W&B. (I also have a reference showing GECAS' B777-200ER fleet having an OEW of 319,700 lbs).

Any feedback will be very much appreciated. I really struggle to believe that the MEW of the B777-200ER without seats could be as low as 260,000 lbs, but I hope my doubts are misplaced.

Thanks in anticipation,

HA

[Wizofoz]

If it is at all helpful, the difference in DOW between EKs 777-200LRs and 777Fs (essentially the same airframe but obviously without seats and fittings) is around 20T, or 44 000lbs, so that seems close to the difference in weights you are talking about.

[oldchina]

alpha

I suggest you use these Boeing figures PLUS at least 5% for customer changes and manufacturer optimism.

http://www.boeing.com/commercial/air...s/777rsec2.pdf

[Hydrogen Alpha]

Thanks for the prompt responses.


If anyone has access to any ACTUAL B777-200/B777-200ER MEWs (sometimes shown as "Basic Weight") which definitely EXCLUDE SEATS, then that would be very useful.


(I'm not asking for either operator or MSN - just MEW, and whether -200 or 200ER).

Thanks, HA

[GlueBall]

Once you have learned to understand that no airframe has an identical weight to any other, even with identical interior configurations, then you may be able to comprehend that there is no identical "MEW" nor any standard "OEW" [operating empty weight]. You may also note that airframes have to be weighed periodically during service; and that without any modifications, the scales will vary from one "C" check to another. For example, an airplane that is weighed with 12 worn brakes would be lighter than an airplane with 12 new brakes.

Even an airframe "without seats" has configuration differences as to a customer's ordered options, such as number of lavatories, type and number of galleys, crew sleeping quarters upstairs, crew sleeping quarters downstairs, crew sleeping quarters on main deck, or no sleeping quarters; individually installed overhead air vents, or no air vents, bulkhead dividers, closets, underfloor wiring to power entertainment modules,...etc, etc. The most you can expect is an "average" empty weight encompassing variations by 1000s of pounds.

[Hydrogen Alpha]

GlueBall

I have some good news for you, GlueBall. I have "learned to understand that no airframe has an identical weight to any other, even with identical interior configurations", and I am therefore "able to comprehend that there is no identical "MEW" nor any standard "OEW" [operating empty weight]". I have not, however, learned this from you since you posted at 14:08 today. I learned it many years ago when I began working in aviation.

If you had understood my post in the sense in which it was written - and it may be my fault that you could not - you would have realized that I was asking for examples of SPECIFIC AIRFRAME MEWs based upon weighing ACTUAL AIRCRAFT.

I said "I'm not asking for either operator or MSN" because I didn't expect anyone to feel able to divulge such information.

[Hydrogen Alpha]

PS: I should also have made it clear that I have also "learned" that seats are not the only Operator Items added to a basic aircraft.