de facto:
Last time I asked the boeing guys why they dont call for a Go around maneuver(ie unstabilized approach) when pilots touch down passed the touchdown zone,I was told it is captain decision
Quote:"VGSI and RNAV glidepath not coincident."
The pilot, regardless of experience level, is well-advised to follow the glidepath rather than the VGSI in such cases, for any number of reasons.Unquote.
Could you please elaborate?
Those Boeing guys need to read FAR 91.175 (c)(1). Further, most U.S. carriers further define a more restrictive permissible TDZ; one for narrow bodies, another for wide bodies.
As to the RNAV glideslope that leads to a decision altitude that path often provides a more optimum TCH than does a VGSI. Also, in many aircraft the VNAV glideslope can be coupled, thus assuring a stablized descent path to DA if not the threshold. And, in marginal visibility conditions the VGSI can be indistinct in the visual segment, especially in the daytime.
Further, if the RNAV glidepath differs from the VGSI path, transitioning from the RNAV glidepath to the VGSI path at low altitude can tend to destablize the aircraft's vertical path at a critically low height.