there is also the proper way of resetting scale on models... (i've had his problem countless times until i picked up the best way of doing it)
you need to have your hierarchy set up so it'll work... meaning all parts must be linked to an 'exterior' node (dummy) and child parts (such as gears or flaps) linked to their parents (wings or fuselage) and so on...
then all you need do is select your top-node (exterior dummy) and hit PgDown, that will select everything below the top node in the hierarchy... then hit Reset Scale... then PgDown again to select the lower level again and Reset Scale again... keep doing that PgDown - Reset thing until you reach the bottom level of the hierarchy (when no new parts are being selected)
that's it!! you just reset the whole model for scale... this method is best because it keeps all animations working (if you reset scale on an animated part that's linked to a parent part, nasty things will happen... and i do mean nasty!!)
also, make sure there are no scale keys set in the timeline... Max uses a color code thing to differentiate keyframe types... red is for position, blue is for rotation (i think) and green is for scale (gray is for vertex or parameter animation) so i recommend you select all your parts at once and take a look at that timeline... see if you can spot any scale keys, if so... delete them (be careful deleting keyframes because the animation will be frozen at the current frame you're on when you delete it... so make sure you're on frame 0)... 3DMax by default makes key for all 3 transforms... so you need to create your keys only when needed (right click the timeline cursor, a popup will err pop up

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i hope this helps... i can't even count how many times i had this problem... luckily now i have my 30 years special effects experience... (oh wait... that might not be me

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Cheers
HarvesteR... 3DMaxBuster (if only... ::) )