Happy to be proven wrong since I'm far from an expert on FMVSS, but what I've seen specifies capabilities like ability to lock and amount of force it must endure, not the actual implementation (mechanical/electrical/etc).
Regardless the article only tells us the "emergency override mechanism did not work". Whether that is electrical or mechanical we can only guess (one would hope mechanical).
FMVSS No. 206 does not directly regulate either interior or exterior door handles. It does, however, impliedly require both interior and exterior door handles or other release mechanisms in its regulation of door locks (see generally, 49 CFR 571.206, S4.1.3 and S4.4.2).
Also UNECE R11[1] soft-require mechanical external door handles.
I think there are also other implied requirements from other sections/directives, such as in crash safety that the doors are required to be locked while crashing, unlocked after a crash, can be opened but not unlatched and flopping. Meanwhile, electrical systems would be required not to pose hazards. I’m guessing those together are ruling out all but flap type manual handles, at least on front side doors.
Is it?
Happy to be proven wrong since I'm far from an expert on FMVSS, but what I've seen specifies capabilities like ability to lock and amount of force it must endure, not the actual implementation (mechanical/electrical/etc).
Regardless the article only tells us the "emergency override mechanism did not work". Whether that is electrical or mechanical we can only guess (one would hope mechanical).