by Zach Grant L1011jock » Wed Jun 05, 2013 4:44 am
337s must be caried for any modifiecation that changes the performance profile or weight and balance of the aircraft. This means any item that ups gross weight, or changes the weight and balance envelope in any way (Robertson Kit for example), as well as any mod that claims a certified performance increase (most speed mods are not certified to increse performance, just claimed to not detract from performance, but a Rayjay turbo mod would fall under this), or any extended range fuel not factory installed (field installed tip tanks, nacelle fuel etc.). So the answer is, yes you need certain 337s in the AFM. The safe way to be is if some fed on a ramp check could see a change from the original configuration of the aircraft, you should probably have documentation that that change was approved...ie. a 337.
-Zach
"Keep it above 5 feet and don't do nuthin dumb!"