Narrative:

While en route to mem at FL330, the autoplt disengaged and would not reengage. ZME cleared us to FL240 and we started down. Our next clearance was to cross walet intersection at 10000'. I asked my copilot to keep me advised as to our distance from walet in 10 NM increments. He suggested that we set up a waypoint for walet in the RNAV. He was not familiar with the lrn 85 RNAV, so I was trying to fly and show him how to setup the waypoint. I was entering the radial and distance, he was giving me the information. He said the distance was 29 NM, and I keyed in 19 NM. When we were turned over to mem approach, he (approach) asked if we were to cross walet at 6000', and I said no, that we were to cross it at 10000'. He then just cleared us to 6000' and told us that turbojets were to cross at 1000' and turboprops were to cross at 6000'. Nothing else was said. I thought we still had 8-10 MM to go, so I started on down to 6000'. We were on the ground at mem and were discussing the flight. He said that we missed our crossing altitude at walet. We went out and turned the power on the aircraft and there it was--19 NM. He said we crossed walet at about 12500'. The copilot I was using this day was a new man that I was looking at as an alternate fr my regular copilot. With the autoplt problems and trying to keep an eye on him, we should have stayed with the first plan of him calling out the distance from the intersection. I informed him that we should be a crew and he should speak up--I depend on him and his input.

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Original NASA ASRS Text

Title: CPR SMT ALT DEVIATION, UNDERSHOT ALT CROSSING RESTRICTION.

Narrative: WHILE ENRTE TO MEM AT FL330, THE AUTOPLT DISENGAGED AND WOULD NOT REENGAGE. ZME CLRED US TO FL240 AND WE STARTED DOWN. OUR NEXT CLRNC WAS TO CROSS WALET INTXN AT 10000'. I ASKED MY COPLT TO KEEP ME ADVISED AS TO OUR DISTANCE FROM WALET IN 10 NM INCREMENTS. HE SUGGESTED THAT WE SET UP A WAYPOINT FOR WALET IN THE RNAV. HE WAS NOT FAMILIAR WITH THE LRN 85 RNAV, SO I WAS TRYING TO FLY AND SHOW HIM HOW TO SETUP THE WAYPOINT. I WAS ENTERING THE RADIAL AND DISTANCE, HE WAS GIVING ME THE INFO. HE SAID THE DISTANCE WAS 29 NM, AND I KEYED IN 19 NM. WHEN WE WERE TURNED OVER TO MEM APCH, HE (APCH) ASKED IF WE WERE TO CROSS WALET AT 6000', AND I SAID NO, THAT WE WERE TO CROSS IT AT 10000'. HE THEN JUST CLRED US TO 6000' AND TOLD US THAT TURBOJETS WERE TO CROSS AT 1000' AND TURBOPROPS WERE TO CROSS AT 6000'. NOTHING ELSE WAS SAID. I THOUGHT WE STILL HAD 8-10 MM TO GO, SO I STARTED ON DOWN TO 6000'. WE WERE ON THE GND AT MEM AND WERE DISCUSSING THE FLT. HE SAID THAT WE MISSED OUR XING ALT AT WALET. WE WENT OUT AND TURNED THE PWR ON THE ACFT AND THERE IT WAS--19 NM. HE SAID WE CROSSED WALET AT ABOUT 12500'. THE COPLT I WAS USING THIS DAY WAS A NEW MAN THAT I WAS LOOKING AT AS AN ALTERNATE FR MY REGULAR COPLT. WITH THE AUTOPLT PROBS AND TRYING TO KEEP AN EYE ON HIM, WE SHOULD HAVE STAYED WITH THE FIRST PLAN OF HIM CALLING OUT THE DISTANCE FROM THE INTXN. I INFORMED HIM THAT WE SHOULD BE A CREW AND HE SHOULD SPEAK UP--I DEPEND ON HIM AND HIS INPUT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.