Vd Dive Speed -- Overspeed Protection?
I'm hoping someone could shed more light on how the FAA handles overspeed/autothrottle protection (e.g., wrt FAR Part § 23.335) in determining Vd (design dive speed).
As I read these regs, and I'm no lawyer (thank God), Section 335(b)(4) is the one manufacturers shoot to use in determining Vd/Md, because it gives the most flexibility. And within this subsection, 335(b)(4)(i) is the paragraph I'm really curious about.
Within this subsection 335(b)(4), paragraphs (ii) and (iii) set a cap on the maximum Mach # for the test if above the transition altitude, so determining Md is easy to understand (e.g., 0.07 Mach above Mmo for commuter aircraft). But Vd in paragraph (i) seems to basically be about the highest speed the plane reaches in a prescribed dive and pullup maneuver while being required to maintain cruise power.
And therein lies my question -- what about aircraft with autothrottle/envelope protection to retard the throttles and prevent speeds from becoming excessive during just such a maneuver? Would the FAA allow such a system to impose a reasonable limitation of the diving speed during this maneuver (say to prevent flutter) -- or would they require the autothrottle/envelope protection be disabled for the test?
Last edited by Mach Stall; 8th Nov 2015 at 09:28.
Reason: clarity