eckhard, JT, et al.
The U.K. CAA issued an AIC on landing performance, relating to Vref +15, this was published at the advent of JAR, after BCAR, thus it may have origins there
‘The Landing Performance of Large Transport Airplanes’
https://www.theairlinepilots.com/for...tairplanes.pdf
Although this document should now be superseded, with what and where remains unknown (CS-25 part 2 ?), yet the advice and background in the AIC may still be very relevant.
This view of max approach speed, Vref +15, was discussed during the formulation of the FSFs ‘Stabilised Approach’ criteria, but Boeing’s view, Vref +20 prevailed, apparently a commercial issue. The finally agreed position was that the conditions for a Stabilised Approach were only recommended (should vs shall), so other manufacturers and operators could use Vref +15; interestingly not a universal understanding - perhaps another economic position (not having to go-around so often).
Boeing’s position left them to decide when and how to reduce speed to the lower value required at the threshold; but that would be by destabilising due to the late deceleration.
ak, IC #3, is there any evidence that Boeing’s latest change is associated with any additional low speed alerting as suggested during discussion / investigations into the 777 Asiana and 737 THY landing accidents?
Do any Boeing aircraft have low speed audio alerting, other than as required for the approach to stall and stall warnings, and EFIS display?