Narrative:

I was PNF on korry 3 arrival into lga. Captain was PF and is a brand new B757 captain. We had the FMS properly set up for the korry 3 followed by the ILS 4 and had briefed it all. ZDC told us to cross eno at FL240 and shortly thereafter switched us to ZNY. The FMS was actually set up as stored for the korry 3: 'eno - FL240A' so it was planning on crossing eno at or above FL240. Neither of us caught the change when the instruction was given to us. As we were descending; we were discussing the descent and caught our own error; realizing we were high. I immediately called ZNY and asked him if he needed a rapid descent for eno and he said no; we could stay on the FMS programmed VNAV descent as published for the korry 3. We crossed eno a little above FL240. There were no conflicts. The captain and I both agreed to redouble our efforts to make sure the FMS and clearance always match. Speaking of arrival dscnts; I have a suggestion that I'd like to pass along for a change to ATC terminology that would go a long way toward reducing confusion and preventing errors. On 'descend via' arrs like this one; and some of the other major arrs (civet in lax; tyssn in las; etc); we already have the FMS fully set up and briefed for both the arrival and the approach well before the descent. ATC typically says something like 'expect the civet 5 ILS 25L transition.' later on; we are told 'descend via the civet 5' as the only instruction. That leaves the pilots left with the task of studying and comparing the FMS; arrival; and approach plates again to make sure they have the correct 'bottom of descent' altitude selected for the 'descend via' portion of the arrival. I know it should not be a problem for professional pilots; but there still is a certain potential for an error to be made in determining the cleared bottom of descent altitude. This problem could be completely eliminated if the ATC controllers would revise their standard phraseology just slightly from 'descend via the civet 5' to 'descend to 7000 ft via the civet 5.' all ambiguity is instantly removed; and a whole link in the potential chain of events in an accident/incident investigation is completely removed. This phraseology also allows a streamlined; easier; clearer way for ATC controllers to change the descent profile for traffic. Currently; in the same situation; if there was a potential traffic conflict for the descending aircraft; the ATC controller would have to issue multiple instructions in the form of an initial 'descend via' clearance followed by an 'amend altitude for traffic call' followed by multiple additional descent instructions now that the aircraft has been removed from the arrival. It would be so much easier for both the controller and the pilots if the controller could use the same phraseology mentioned above. In this case; say there's a potential conflict aircraft at 9000 ft so the controller simply says 'descend to 10000 ft via the civet 5.' pilots then instantly know the desired bottom of descent clearance limit and also know that the controller still wants them to meet all higher crossing restrs on the arrival. Later in the descent; when the controller realizes that the traffic at 9000 ft is not going to be a factor; he can follow up with another instruction 'continue descent to 7000 ft via the civet 5.' the pilots will already still be on the FMS descent path anyway; so they can continue to meet the descent profile as published. Everyone's happy! It's clean; totally unambiguous; and definitely safer phraseology!

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Original NASA ASRS Text

Title: ACR ON DESCENT TO LGA EXPERIENCED SOME CONFUSION REGARDING THE DESCENT VIA PHRASEOLOGY; SUGGESTING PHRASEOLOGY CHANGES.

Narrative: I WAS PNF ON KORRY 3 ARR INTO LGA. CAPT WAS PF AND IS A BRAND NEW B757 CAPT. WE HAD THE FMS PROPERLY SET UP FOR THE KORRY 3 FOLLOWED BY THE ILS 4 AND HAD BRIEFED IT ALL. ZDC TOLD US TO CROSS ENO AT FL240 AND SHORTLY THEREAFTER SWITCHED US TO ZNY. THE FMS WAS ACTUALLY SET UP AS STORED FOR THE KORRY 3: 'ENO - FL240A' SO IT WAS PLANNING ON XING ENO AT OR ABOVE FL240. NEITHER OF US CAUGHT THE CHANGE WHEN THE INSTRUCTION WAS GIVEN TO US. AS WE WERE DSNDING; WE WERE DISCUSSING THE DSCNT AND CAUGHT OUR OWN ERROR; REALIZING WE WERE HIGH. I IMMEDIATELY CALLED ZNY AND ASKED HIM IF HE NEEDED A RAPID DSCNT FOR ENO AND HE SAID NO; WE COULD STAY ON THE FMS PROGRAMMED VNAV DSCNT AS PUBLISHED FOR THE KORRY 3. WE CROSSED ENO A LITTLE ABOVE FL240. THERE WERE NO CONFLICTS. THE CAPT AND I BOTH AGREED TO REDOUBLE OUR EFFORTS TO MAKE SURE THE FMS AND CLRNC ALWAYS MATCH. SPEAKING OF ARR DSCNTS; I HAVE A SUGGESTION THAT I'D LIKE TO PASS ALONG FOR A CHANGE TO ATC TERMINOLOGY THAT WOULD GO A LONG WAY TOWARD REDUCING CONFUSION AND PREVENTING ERRORS. ON 'DSND VIA' ARRS LIKE THIS ONE; AND SOME OF THE OTHER MAJOR ARRS (CIVET IN LAX; TYSSN IN LAS; ETC); WE ALREADY HAVE THE FMS FULLY SET UP AND BRIEFED FOR BOTH THE ARR AND THE APCH WELL BEFORE THE DSCNT. ATC TYPICALLY SAYS SOMETHING LIKE 'EXPECT THE CIVET 5 ILS 25L TRANSITION.' LATER ON; WE ARE TOLD 'DSND VIA THE CIVET 5' AS THE ONLY INSTRUCTION. THAT LEAVES THE PLTS LEFT WITH THE TASK OF STUDYING AND COMPARING THE FMS; ARR; AND APCH PLATES AGAIN TO MAKE SURE THEY HAVE THE CORRECT 'BOTTOM OF DSCNT' ALT SELECTED FOR THE 'DSND VIA' PORTION OF THE ARR. I KNOW IT SHOULD NOT BE A PROB FOR PROFESSIONAL PLTS; BUT THERE STILL IS A CERTAIN POTENTIAL FOR AN ERROR TO BE MADE IN DETERMINING THE CLRED BOTTOM OF DSCNT ALT. THIS PROB COULD BE COMPLETELY ELIMINATED IF THE ATC CTLRS WOULD REVISE THEIR STANDARD PHRASEOLOGY JUST SLIGHTLY FROM 'DSND VIA THE CIVET 5' TO 'DSND TO 7000 FT VIA THE CIVET 5.' ALL AMBIGUITY IS INSTANTLY REMOVED; AND A WHOLE LINK IN THE POTENTIAL CHAIN OF EVENTS IN AN ACCIDENT/INCIDENT INVESTIGATION IS COMPLETELY REMOVED. THIS PHRASEOLOGY ALSO ALLOWS A STREAMLINED; EASIER; CLEARER WAY FOR ATC CTLRS TO CHANGE THE DSCNT PROFILE FOR TFC. CURRENTLY; IN THE SAME SITUATION; IF THERE WAS A POTENTIAL TFC CONFLICT FOR THE DSNDING ACFT; THE ATC CTLR WOULD HAVE TO ISSUE MULTIPLE INSTRUCTIONS IN THE FORM OF AN INITIAL 'DSND VIA' CLRNC FOLLOWED BY AN 'AMEND ALT FOR TFC CALL' FOLLOWED BY MULTIPLE ADDITIONAL DSCNT INSTRUCTIONS NOW THAT THE ACFT HAS BEEN REMOVED FROM THE ARR. IT WOULD BE SO MUCH EASIER FOR BOTH THE CTLR AND THE PLTS IF THE CTLR COULD USE THE SAME PHRASEOLOGY MENTIONED ABOVE. IN THIS CASE; SAY THERE'S A POTENTIAL CONFLICT ACFT AT 9000 FT SO THE CTLR SIMPLY SAYS 'DSND TO 10000 FT VIA THE CIVET 5.' PLTS THEN INSTANTLY KNOW THE DESIRED BOTTOM OF DSCNT CLRNC LIMIT AND ALSO KNOW THAT THE CTLR STILL WANTS THEM TO MEET ALL HIGHER XING RESTRS ON THE ARR. LATER IN THE DSCNT; WHEN THE CTLR REALIZES THAT THE TFC AT 9000 FT IS NOT GOING TO BE A FACTOR; HE CAN FOLLOW UP WITH ANOTHER INSTRUCTION 'CONTINUE DSCNT TO 7000 FT VIA THE CIVET 5.' THE PLTS WILL ALREADY STILL BE ON THE FMS DSCNT PATH ANYWAY; SO THEY CAN CONTINUE TO MEET THE DSCNT PROFILE AS PUBLISHED. EVERYONE'S HAPPY! IT'S CLEAN; TOTALLY UNAMBIGUOUS; AND DEFINITELY SAFER PHRASEOLOGY!

Data retrieved from NASA's ASRS site as of May 2009 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.