PLT OF E135 FAILS TO MAKE DSCNT XING RESTR ON DYLIN ARR TO EWR.
Synopsis
PLT OF E135 FAILS TO MAKE DSCNT XING RESTR ON DYLIN ARR TO EWR.
Narrative
WE WERE DSNDING INTO EWR ON THE DYLIN 2 ARR. THE ARR HAS MANY XING RESTRS WHICH I PREPROGRAMMED INTO THE FMS VNAV. THE FIRST 2 XING RESTRS REQUIRED XING THE FIXES AT OR ABOVE AN ALT AND THE THIRD XING RESTR REQUIRED XING THE FIX BTWN 11000 FT AND 13000 FT. THE DSCNT RATE DISPLAYED BY THE FMS TO CROSS THE THIRD XING RESTR BTWN 12000 FT AND 13000 FT WAS 1500 FPM. THIS RATE MET THE FIRST 2 AT OR ABOVE XING RESTRS SO I BEGAN DSNDING AT 1500 FPM. WE MET THE FIRST 2 XING RESTRS BUT UPON XING THE SECOND FIX THE FMS UPDATED OUR DSCNT RATE TO MEET THE THIRD RESTR AND DISPLAYED A DSCNT RATE OF 5400 FPM. I BEGAN DSNDING AS RAPIDLY AS POSSIBLE BUT WE CROSSED THE FIX APPROX 2000 FT TOO HIGH. AS SOON AS WE WERE AWARE THAT WE WERE NOT GOING TO MAKE THE RESTR WE ADVISED ATC. AFTER ANALYZING WHAT HAPPENED; I DETERMINED THAT I DID NOT INTERP THE FMS INFO CORRECTLY. AT THE TIME I THOUGHT THE DSCNT RATE INFO FROM THE FMS WAS THE DSCNT RATE REQUIRED TO MEET THE RESTRS FROM OUR PRESENT POS. IN FACT THE DSCNT RATE INFO DISPLAYED IS THE DSCNT RATE REQUIRED TO MEET THE RESTR IF THE PRIOR XING RESTR IS MET AT THE MINIMUM ALT. BECAUSE I DID NOT CROSS THE PRIOR FIX AT THE MINIMUM ALT WHEN WE PASSED THIS FIX; THE FMS UPDATED ITS INFO AND SHOWED THAT WE WERE HIGH. AT THIS POINT THERE WAS INSUFFICIENT TIME TO RECOVER. IN THE FUTURE; I WILL DSND TO MEET XING RESTRS AT THE MINIMUM ALTS. I BELIEVE BETTER TRAINING ON THE USE OF THE FMS AND AN IMPROVED DISPLAY COULD HAVE PREVENTED THIS OCCURRENCE. PERHAPS THE FMS COULD BE DESIGNED TO PROVIDE AN ADVISORY WHEN THE PRESCRIBED DSCNT RATE APCHS A RATE BEYOND THE ACFT PERFORMANCE CAPABILITIES.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.