I have heard some say they would use another due to The 3003/4 are not recommended due to the extreme vibration enviroment of heli's.
"Both the S3003 and S3004 use a direct drive potentiometer. What that means is the output gear is connected directly to the potentiometer. Since the output gear is connected directly to the pot it is very possible that vibration will damage the pot. This is why we do not recommend these servos to be used in helis. Helis generate a very high frequency vibration due to the high rpm of the engine and the close proximity of the engine to the servos. "

http://www.futaba-rc.com/faq/product-faq.html#q634