If you read the FAR's carefully you will not find one particularly titled Performance in OGE or IGE hover. Performance testing includes establishing weights at min spec power, H/V envelopes and controllability and engine characteristics in omnidirectional winds at 17 kts.
During compliance with these regs. data is collected, and because it is essential information, used to compile flight manual IGE and OGE charts.
Not absolutely certain but I believe Bell is the only manufacturer to publish IGE/OGE charts with data when the wind is right on the nose. See Area A (Omni directional wind performance) and Area B (Enhanced Performance in calm conditions or when wind on the nose) in the B206 RFM.
Additional information on compliance with the FAR's can be find in AC27 and AC29. Provides good information for all concerned.
Last edited by Gemini Twin; 3rd Jul 2013 at 20:18.