# Why will the 777X be tested for crosswind handling with wingtips raised?

As existing regulations do not cover the folding wingtips, the FAA issued special conditions, including proving their load-carrying limits, demonstrating their handling qualities in a crosswind when raised

Why? Especially when this question says:

The 777X family (777-8/-9/-10) features wingtips that fold up on the ground to let the aircraft fit in tight spaces. These have to be extended and locked in place before a revenue flight can take place,

So, what is the point of certifying the 777X for wingtip up flight? I haven't found a reason for this in Wikipedia either. Is it for ferry flights or something?

• I'm unclear on what "raised" means, is that retracted or extended? The wingtips on the 777X shouldn't ever be locked in a "raised" position AFAIK. Sep 8 '20 at 15:49
• @zymhan And I'm not sure what you mean by "retracted or extended"? I'm not a native English speaker, but to me these words don't make sense when talking about the 777X wingtip. Raised and lowered seem more intuitive to me. Sep 8 '20 at 15:52
• @zymhan actually yes, it does sort of mean retracted, though the term would misleading in this case (I think). Anyway, pretty much anyone who's familiar with the 777X would know that a raised tip is a folded tip Sep 8 '20 at 15:54
• Boeing also has to demonstrate “acceptable” handling qualities during crosswind conditions, even if one wingtip fails to completely fold. This would indicate that they are not simply looking at Open vs Closed.flightglobal.com/faa-sets-certification-rules-for-777x-wingtip/… Sep 8 '20 at 16:16
• @zymhan: Some parts of that article sound almost like a threat in hindsight, now we know what would happen only 4 months later: "As with any critical airplane systems, like flight controls, […] Boeing uses a hazard class determination for certain extremely improbable airplane level failure events to drive the appropriate high-integrity system architectures, design redundancies, and safety features to preclude such events,” Boeing says. “This same safety and certification methodology was used with our new folding wing tip […]" Oh really, they applied the same safety methodology as for MCAS? Sep 8 '20 at 21:58