The information you require is normally contained in the Configuration Deviation List of the Flight Manual. The A330's is as follows:-
(m) One may be missing provided hole is covered.
Increase fuel consumption by 1 %.
Reduce the takeoff and approach climb
performance limiting weight by 2.5 %.
Reduce the one engine inoperative ceiling by
250 ft.
There is no time limit on CDl ITEMS but...
GENERAL
The configuration deviation list belongs to chapter 2 LIMITATIONS ol this flight manual. Flight with certain secondary airframe missing parts is possible, as indicated in this kst Any part not included in this list must be considered as necessary.
It is important to repair the airplane at the first airport where repairs or replacements may reasonably be made, since additional malfunctions may require the aircraft to be taken out of service. A Letter (m) against an item indicates that some maintenance action is necessary to permit flight with these parts missing. Refer to he related Section of the Maintenance Manual for this information,
LIMITATiONS
No more then one part or one combination of part of one system may be missing Parts of different systems may be simultaneously missing, unless otherwise specified with this list. When a missing part introduces additional limitation this limitation is indicated in the Remarks and/or exceptions column. This limitation comes in addition to limitations of chapter 2 of Flight Manual. It must be clearly indicated by a placard on the captains instrument panel
PERFORMANCE
Perfomance penalties are cumulative unless specific penalties for particular combinations of missing parts are indicated. These take off, en route and landing penalties apply to the most limiting corresponding weight.
Hope this helps.
DTG