Matthew et al:
Aside from the side and rear wind issue, I can think of no other instance where numbers etc., in the limitations section are not absolute limits to be adhered to. In fact, exceeding them will invalidate your certificate of airworthiness (another subject).
Whether the limitations are 'economic' (as in being very conservative) is not the issue. The manufacturer is under no obligation to tell you why a limitation is a limitation - the reasons for limitations are legion.
I would never suggest that flying outside the limitations can be done without consequence (engineering, legal or otherwise). What I was saying was that, as worded, the side and rear wind phrase should not be considered as limiting, because it's not worded as a limitation.
The R-22 manual as an example - 'demonstrated up to 9,800... see performance for maximum weight'. This should be interpreted that at the maximum weight for that altitude for hovering (in ground effect or out of ground effect isn't clear from what was posted), that there will be sufficient yaw control up to those winds.
Now - how were the tests done? The tests for in ground effect would be done at the IGE hover height, in absolutely calm winds using a pace truck to generate 17 knots of side / rear wind.
So - out in the real world, in a mountain meadow, how would you know what the real wind speed is?
Assuming you did know the wind, when did you ever see a steady wind of 17 knots?
Would you hover at the flight manual IGE hover height in that much wind, or would you hover higher?
Now- what's the definition of 'sufficient' yaw control that the FAA needs to have demonstrated? It means that at that side wind condition, you can generate a yaw rate- how much of a yaw rate you consider to be sufficient is a judgement call. Would that much control margin be enough in gusty conditions? Don't know, as we don't specify a gust spread for this condition.
All this points to the reason why this statement isn't really shown as a limitation- it can't be a hard limit because of the impossibility of respecting it.
Hope that clears things up slightly.
Shawn